stec74
New Head-Fier
- Joined
- Mar 4, 2015
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One year has already passed since I started looking for a good amplifier for my HD800.
As you know very well, partially because you need to try the various combinations (and it is always quite hard), partially because I had fallen in love with the previous model (see here: http://www.ilgazeboaudiofilo.com/t23716-estro-armonico-otl-sennheiser-hd800), eventually I opted for OTL Amplifier by Estro Armonico.
I was taking my first few steps into the Audio world with a capital “A”, and I was literally freezed at what I could listen to in the weeks when they sent me their test unit to enable me to assess it. Up to the point that I ordered Lorenzo Betti and Massimiliano Fraboni a new Amplifier and made up a little purchase group to support them in the development phase.
The goal was to obtain a device similar to the original one from the point of view of the sound, keeping all its pluses, namely timbre, dynamics, transparency, speed, while correcting its imperfections and making it more versatile.
The only formal request was to improve a bit the punch for the headphones it would be used with, Sennheiser HD800, which was not impeccable in the model I had tested.
One year has passed and the new Amplifier is here beside me, its bulbs as warm as little ovens, as it waits for me to push “play” on my CD player.
Let’s see what has changed from the original device I tested last year…
TECHNICAL SPECIFICATIONS:
POWER: 3.5 W for 600 Ohm / 1.75 W for 300 Ohm
GAIN: 15 db
S/N RATIO: over 90 db
FREQUENCY RESPONSE: 5-100,00 Hz
SENSITIVITY: 150 mV
POWER SUPPLY UNIT SIZE: 22 L z 30 D x 13 H, 11 kg
AMPLIFIER SIZE: 32 l x 30 D x 5.5 H, 4.6 kg
TUBES: pre 2x 6H23 (or ECC88), final 2x 5998 (or 421A WE), rectifier 1x 5U4/5931 (GE / Sylvania / Svetlana)
SELLING PRICE: € 1800
http://www.estroarmonicoaudio.com
https://www.facebook.com/Estro-Armonico-492197340828823/
MANIFACTURE:
It is a professional product, home-designed and manually assembled.
This is more than clear, despite they have paid a lot of attention to its appearance.
However, this is not a defect, but should be seen as a precise feature, characterising each electronic device manufactured by this company.
Each detail has been taken care by the designer personally, and this ensures greater quality than any industrially manufactured product.
The rest is just aesthetic details.
Paying a visit to the laboratory is like taking a real journey through time.
To a different age, when we had the time to stop and think about things, rather than just “do them”…
Let’s start from the frame.
From a technical point of view, the frame (original project) is made of non-magnetic AISI 316 stainless steel of thickness 20/10 3 mm for the heat, with 3 cm whole wood lateral elements, 2mm aluminium grid at the bottom and 3 feets. It is connected to the power supply by a 1.5 m cable with apowercon connector.
For the power supply, the Nordlys frame, another EA project, was used. It is fully made of 5mm aluminium, with 4 feets and powercon power connections (IEC on demand).
The first thing that draws your attention is its size! And in this respects, photos cannot give you an idea.
Both the head and the power supply unit are twice as big as those in the little system I previously tested. In particular, the power supply unit is titanic!
In other words, you can see and feel its 11 kg, entirely!
The generated power is 350VA and it is very heavy, but all in all it is more than acceptable and separating the system into two units makes sense.
Inside Components.
I am not knowledgeable in electronics and I cannot assess the quality of each single component, nor can I understand the planning logic behind the choice of the components, but I can tell you what the results of these choices are!
The project is very similar to the original one, therefore, initially the idea was simply to improve the quality of components, while keeping the project unaltered.
In any case, we were focusing on the quality, taking into consideration high-quality military and industrial components whose costs would be affordable from the point of view of the final price.
As the project developed and the first few tests were being carried out, Lorenzo took a passion in it and started to realise that it
was possible, with some modifications, simplify it even more and create something remarkably better.
From that moment, a long period of experiments and search for the best components started, until they were selected, involving even Lorenzo’s persona stock of items he had carefully selected through the years.
Needless to say, the cabling is totally in air, with 60/40 Copper/Silver solid core cables.
This cables are normally used in the aeronautic, airspace and navy sectors, and are the standard of choice for EA.
Transformer and inductance were made manually on the basis of the specification, using 4% iron-silica grain-oriented plates.
Finally, they were dipped into oil (double passage) and the transformer was “tarred” with what looks like anti-drumming paint and assembled on the power supply unit on rubber pins. All this resulted in great improvements of the vibrations
One specification: when I say “military components”, I do not refer to consumer components produced for military purposes and freely available on the market.
I mean real military components, disassembled, one by one, from US and USSR instruments not used anymore, chosed and bought in stocks directly on place! I worked as a radar operator on
military ships for three years… we are speaking about something completely different and made for a single purpose: to always work with those specifications, resisting everything without breaking (at least, that is the idea). It is not consumer products and it does make a difference, believe me!
The same holds true for the industrial components used.
Here, the quality standard is very high too and the components come from old scientific devices. Other things, obviously, are consumer products, but they are always high quality ones (e.g. alps black beauty potentiometer, Mundofr/Jensen condensers).
Here is a list of what is inside (and outside) the two boxes:
4 RCA NEUTRIK IN (GERMANY YARBO made of Rhodium / custom Silver upon request)
2 RCA NEUTRIK OUT (GERMANY YARBO made of Rhodium / custom Silver upon request)
1 FEME IN commuter with gold contacts
2 headphone OUT with silver contacts (Neutrik Nj3FP6C-BAG)
- PRE-AMPLI circuits, with commuter
- Standard Powercon 20A power supply connector (with cable included) / IEC upon request
1 ALPS RK40 Black Beauty logarithmic potentiometer
2 Mundorf Supreme OUT Caps Silver/Oil/Jensen with Copper reinforcements – 1uF
2 Switching Electrolytic caps
2 Tubes 5998
2 Pre tubes 6H23 (replaceable with ECC88)
1 Rectifying tube 5U4 (GE / Sylvania / Svetlana)
1 Stainless steel volume knob, equivalent to Nordlys
- 350VA separate power supply unit, with 4% iron-silica grain-oriented plates handmade manufactured
- Kiwame/Alle Bradley resistances
- DALE Armored cathode resistances complying with military norms (25W/1% tolerance)
- Air cableing with 60/40 Copper/Silver thread coated with Teflon
- Non-magnetic AISI 316 stainless steel AMPLIFIER frame of thickness 20/10 with upper plate bearing a logo, 3 removable feets and wood lateral pieces
- Aluminium Nordlys POWER SUPPLY frame of large thickness and stainless steel plate, main switch
SETUP
The setup used for the tests is the same as all my setups, with some minimal adds:
Sounds used:
My favourite genres range from rock to jazz, blues, without neglecting some electronic and experimental contaminations.
The CDs/SACDs used for this test were the same already as in the review of the previous model, plus a few high-resolution files, namely:
Pink Floyd (The Wall / Dark Side of the Moon, CD remasterised in 2011 by James Guthrie), BB King (Live at the Apollo, Verve), Dire Straits (Brothers in Arms, SACD), Doug Macleod (There's a Time, HDCD), The Ultimate Chesky Demostration Disk HD Tracks ( http://chesky.com/album/ultimate-demonstration-disc-ud95 ).
For the electronic part:
- Cambridge Audio BD751 Universal Player
http://www.ultrahighendreview.com/cambridge-audio-azur-751bd-universal-blu-ray-player/
- Oppo 105 Universal Player
http://www.tnt-audio.com/sorgenti/oppo_bdp105.html
- FiiO X5 (1st Jan) digital player
http://www.head-fi.org/products/fiio-x5-high-res-portable-music-player/reviews
- EstroArmonico OTL SIGNATURE headphones amplifier
http://www.estroarmonicoaudio.it/
- Amplificatore portatile Fiio E12 DIY Limited
http://www.head-fi.org/products/fiio-e12-diy-limited-edition-portable-amp-headphone-slim-amplifier
- Sennheiser HD800 headphones
http://www.stereo-head.it/2013/07/cuffie-sennheiser-hd800-recensione/
- Sennheiser HD650 headphones
http://www.tnt-audio.com/casse/headphones_test.html
Final details:
- Furutech single thread silver signal wires (home-built – 19AWG 0.9 mm single-thread, protected by a copper insulation and PVC protection, V&M connectors)
http://www.furutech.com/2013/01/29/1496/
http://www.audioselection.it/product.php~idx~~~1924~~V+_+M+CS1032~.html
- Mundorf signal cables (home-built – 4 silver +1% gold 24AWG single wires, 0.5 mm each, intertwined without protection, V&M connectors)
http://www.audioselection.it/product.php~idx~~~328~~MUNDORF+SGW+105~.html
http://www.audioselection.it/product.php~idx~~~1924~~V+_+M+CS1032~.html
- Mundorf signal cable (home built – 4 silver +1% gold 24AWG single wires, 0.5 mm each, intertwined with double protection, WBT Nextgen connectors)
http://www.audioselection.it/product.php~idx~~~328~~MUNDORF+SGW+105~.html
http://www.wbtusa.com/pages/0110ags.html
- Ebony feets with zircon spheres V&M SYMBIO P1-33 for uncoupling electronics
http://www.audioselection.it/product.php~idx~~~1742~~V_M+SYMBIO+P1_33~.html
- Home-build feets, based on the V&B model
(oaken frame, silicon nitride 9.5 mm spheres)
http://www.rgpballs.com/it/prodotti/SFERE/SCELTA-RAPIDA/CERAMICA/sfere-in-nitruro-di-silicio-si3n4
What a beautiful surprise! The best setup was found to be rather different from what I found for the previous model.
Let us see why:
Source.
Before the best source was the Oppo player, now it is the Cambridge one.
The pleasant news is that, besides being the player I have at home, the Cambridge one is also a previous generation compared to the Oppo. The sound is simply more natural, I don’t know how to define the concept better. Besides the analytical nature of the Oppo sound, the musicality is simply better.
Moreover, it was simpler to interface the Cambridge player, this time.
With the previous tests (old EA model), after connecting the Oppo and noticing that the sound improved with a proper adjustment of the signal outgoing volume, we had the impression that the default Cambridge fixed outgoing volume was too loud, thus compromising my listening experience.
The feel I had was that of a bloated and less controlled sound than the Oppo.
Now this sensation has disappeared completely, this proves how Cambridge performed well with this player!
Signal cables.
The best wire is still the home-built Mundorf one, here in its double protected version with WBT Nextgen connectors. In comparison with the previous wire, we noticed a better focus on the instruments and a remarkably better scene, therefore this is our reference signal wire.
Feets.
The home-built feets proved to be better than the Symbio ones, I really didn’t expect that!
In this setup, the Symbio ones tend to get dry a lot, whereas the oaken ones remain unaltered, thus simply improving what can be improved… excellent, at a very low price (almost nothing), they are a bargain, I’ll haste to build some more!!!
Evidently, the older EA model's power supply unit benefited from this detail, whereas here it is not necessary or is even harmful… I would like to point out the enhanced transparency and dynamic excursion, whereas my friends pointed out the rhodium connectors… never mind
Even under the CD player, the new feets perform very well.
However, here I had the impression that the enhanced impact is due to the vibration dissipation system due to the sphers, rather than the wood.
For the details of the home-building of these feets and the principles on the basis of which the various materials work and are selected, you may read and take part in this (italian, sorry) thread:
http://www.ilgazeboaudiofilo.com/t27371-piedini-a-sfere-oscillanti-diy
Rectifying tubes and caps combo.
A critical part of this test, and the one which required the longest time for the final adjustments.
As you certainly know better than I do (I have only just learnt it), the sound of a tube system like this is deeply affected by the performances of some components more than others.
Leaving alone the pre and final tubes for a second (we will not deal with them), I am going to discuss the signal caps and the power supply rectifying tube.
The right combination for “your” sound in this amplifier is to be looked for, by investigating the proper combination between these two critical components.
Originally, some Mundorf Supreme Silver Oil elements were used and the tube which, in theory, would guarantee the greatest power supply, namely General Electric (in any case, the difference with the others is minimal).
It was supposed to be the winning choice, but something in the sound was not convincing me, so I decided to test some more combinations.
I talked about it with Lorenzo Betti and Massimiliano Fraboni, and we eventually decided to carry out a day of wide ranging tests in their laboratories.
On the table, we had everything we needed: the previous amplifier I originally tested and the new one in two versions, one with Mundorf caps (about 90 hours of testing), the other with Jensen caps with copper reinforcements (about 80 hours of testing).
This is what I initially found (grades from 1 to 5 stars, with reference to the initial setting, which is the ideal one in my opinion):
- Mundorf + GE: *
The first combination I tried at home, which could not convince me!
Too dry and sparkly for me, the instruments sound fine but the voices get harsher;
- Mundorf + Sylvania : **
As for the general sweetness, it is a bit better, but it is still a bit too sparkly for my tastes;
- Mundorf + Svetlana : ****
A further improvement, sweeter and rounder sound. It is a matter of personal tastes;
- Jensen + GE : **
A strange combination, what you gain with the caps, you lose with the rectifying tube.
- * Jensen + Sylvania : ****
A good combo, nothing to remark, except that the choice is due to your tastes; I liked it;
- * Jensen + Svetlana : *****
Full sound and rich of harmonics.
At the beginning of this lab test, as for my personal taste, it was the perfect combination, with all kinds of music, it can compete with the previous one and the Mundorf-Svetlana combination;
I believe the list above is self-explanatory, you should not have any doubts about what I brought back home!
I must admit I was impressed at the remarkable differences I found between all these tests! I spent the whole day changing heads, power supply units, tubes, caps…
At the end of the day I was exhausted, but I have to say that it was really worth it!
(Thanks Lorenzo and Massimiliano for your patience and support!
)
LISTENING
The most important parameter of all. Eventually, what does this amplifier sound like?
Very, very, very WELL indeed! We were all favourably impressed at the results you can achieve with this amplifier, as well as its versatility.
Svetlana proved to be a marvellous valve, which I can describe using only one word: MUSICAL!
The GE → Sylvania → Svetlana shift showed an improvement in this respect.
With GE, it seems that you deal with a solid state, in the cold and sharp meaning of the term. Progressively, for the other two, this situation improves remarkably and the harmonics start to reappear in a superb way!
The Mundorf caps, instead, did not fully satisfy me, it was very hard for me to understand what I was really listening to and why…
I mean, I expected a very different sound. They are hyper-analytic as the best modern solid state, maybe even more than the Jensen ones, but also much more brilliant than I expected!
Combined with the GE, indeed, you cannot listen to them for more than 15 minutes without feeling tired.
Instruments are perfect, whereas voices are as sharp as razors… When I listened to this combination for the first time, I didn’t know what to think about this slightly metal veil which seemed to lie on everything.
Analyticity, monstrous transparence, details, speed as the very best solid state… it was all there, but the listening emotion which the previous model had given me was missing!
In order to be sure about the results, the tests were carried out both with the electronic components listed in this review and with a Lector CDP 7 TL Tube.
Unfortunately, not even such a valve and famously sweet and well-sounding source as this one could help, and this parameter did not change at all.
The replacement of the rectifying tube from GE to Svetlana changed everything, everything became as different as cheese from chalk, and everything started sounding great again, like magic!
So why should you choose Jensen rather than Mundorf?
Probably, it is only a matter of personal tastes.
By listening to them one after the other, with the same reference musical pieces, I realized that I preferred a less analytical and more touching, velvety sound.
Moreover, the Jensen caps made the HD800 more tolerant to sibilating sounds than the Mundorf ones.
Not less transparent, do not get me wrong!
In this respect, we are dealing with absolute reference levels!
In some classical music recordings (CDs) you can hear a moped in the distance outside the studio and in There’s a Time by Doug Macleod (HDCD) you can hear a chair creaking and a (single) cricket sing for a few instants at different times during a couple of pieces (this makes me think it was an outdoor evening recording). In other recordings you can hear the musicians breathing into their instruments and pressing the keys of their saxes and trumpets, in some you can even hear it on the piano… Impressive!
As for the dynamics, very close to the theoretical limits, “you can hear it all”, as Lorenzo Betti stated.
Bad recordings, instead, remain bad… but in any case, who wants to listen to them?
Anyway, after all they both sounded great and it was only a matter of personal tastes!
The final definition I can give is that with the Mundorf caps you have the impression that it is a solid state, whereas with the Jensen ones everything is about tubes. Both are top quality!
I felt particularly enlightened by the Demo Chesky HD tracks.
For those who haven’t had a chance to listen to them, all the recordings in question have a guiding voice which tells us where, how and when they were recorded, why they have been proposed, what they intend to highlight with each musical piece (dynamics, transient, fire, etc.) and what should reach your headphones.
I must admit I had a lot of fun listening to this Demo! Besides the pieces proposed, all wonderful, I did not find it difficult at all to immediately identify the feature which each piece meant to highlight, this obviously proves the high quality of the whole listening system!
All the instrument sounded correct, well focused and distinguishable.
The planes seemed correct to me, just like the tridimensional space of the stage.
In one of the pieces, for instance, the guiding voice told us that on the stage there was just one saxophone player at a distance of 3 metres from the microphone and gave us all the spatial references about the side and back walls, the size of the studio, etc. It is wonderful to realize, without any efforts, that the sax is really there, at the same distance specified, both from you and from the microphone!
And you can easily distinguish the notes from the pressure of the keys and the musician’s breath…
Same feelings for all the other musical pieces… I believe this is the best example you can give to properly provide information about this amplifier!
Comparison with the previous OTL EA. (http://www.ilgazeboaudiofilo.com/t23716-estro-armonico-otl-sennheiser-hd800).
On the back side of the model I took home there is a suitably made plate, bearing the signature of the designer silk screened. THAT’S ALL. No further word should be necessary.
When you speak about it, Lorenzo’s voice changes completely and you can feel the passion and pleasure he poured in this product. In his and Massimiliano’s opinion, this is the most transparent and best sounding headphone amplifier ever produced in their laboratories.
I have only one definition: a wire with gain!
Or in any case, the closest thing to this definition which I have ever had a chanceto listen to!
A comparison with the previous model simply makes no sense.
I thought it was a wonderful Amp (and indeed it is!) and that not much could be improved, but I was very wrong because, in comparison with the new one, it sounds like a portable battery radio!
To me, this is absolutely incredible! I had the impression that it would sound better, but I could have never expected such a huge gap!
Comparison between HD800 and HD650.
The choice to have two headphone connectors proved to be absolutely right!
The convenience of not having to continuously unplug a set of headphones to put on another one, pausing the recording and then going back to the precise point you were listening to… it is priceless!
Simultaneous listening in this way was so incredible from this point of view, and we could verify that this amplifier did not betray us at all, managing the HD800 in a perfect way and effortlessly at any volume.
Despite this, it was a very, very difficult comparison.
If the differences were evident before, now they have become very slight.
You can immediately sense the superiority of HD800, but the 650 model is not the headphones it was before this amplifier, now it Sounds (with a capital “S”) really and really good!
And this was a big surprise, since this amplifier was tailored to the HD800 (headphones which stayed in the laboratory for all the time necessary), therefore…
Now it is much more open, bright andbetter performing in the low part.
Again about Doug Macloud, the 650 was even preferable for some musical pieces, due to its “old-style” settings, more suitable for this genre than its elder sister.
And what about the HD800? It has grown stronger and found fantastic bass, which we were blissfully unaware it could have! Really, you still do not know what bass these headphones can have if they are managed properly! Powerful, very deep, but stable and controlled, never aggressive.
The loud and very loud tones are all there, sweet and never sharp or harsh.
The sibilating sounds are only present if they are present in the recordings (and if their quality is good, they will never annoy you! )
The average range is really remarkable, a jewel… I can only tell you that the voices are REAL, ALIVE.
With both headphones, both male and female voices are such as to intimately touch you!
If the HD800 are finally able to reach their full potential, perhaps the real miracle is the performance with the HD650 ones, in certain respects very close to their elder sister.
I am seriously thinking about buying one…
At this point, I am curious to try some more headphones, HiFi Man, Audeze…
If my impression is correct, this amplifier can manage everything well…
A COUPLE OF MONTHS LATER
(*) IMPORTANT NOTE: at the end of a long testing period, about a couple of months after the first few listening sessions, I performed a new series of tests by replacing Svetlana with Sylvania. I did so because the sounds of the caps has changed in time and I wanted to check whether my initial feelings still held true.
And I had a big surprise!
The situation diametrically changed in favour of Sylvania, clearly better than Svetlana at the end of the break-in!
I thought I had found the perfect combination, but I was definitely wrong, there was something much, much better!
Airy, well-defined, with an equally deep but much more stable basses, crystal-clear and never sharp (and possibly even more refined and sweeter than before) loud and very loud sounds.
Once again, very airy instruments and a huge soundstage!
In comparison, Svetlana now sounds close and “swollen”.
It is still a good tube, but there is no comparison at all… I would assess them 6 and 10, respectively, in a 0-10 scale, that should be clear…
Evidently, the exuberance and strength of Svetlana somehow made up for the lacks I failed to notice immediately.
After all, experience can only be achieve with time… I am taking notes about everything, some day I will go through it again…
At this point, I would like to review the table above and make the following modifications:
- Jensen + Svetlana : ****
Rich sound, full of harmonics.
It is an excellent combination, with a great push, especially in the low tones, and compatible with any musical genre.
However, I would recommend listening very well once after a full break-in, since the sound might seem a bit closed and “swollen”, especially if compared with that of more “educated” tubes like Sylvania;
- Jensen + Sylvania
(5U4 standard) : *****
After the end of the tests, it proved to be the perfect combination!
A lot of air between the instruments, a huge soundstage, deep and very controlled low tones, crystal-clear and never sharp high and very high tones.
A valve which contributes to a very relaxing sound and, more importantly, a very well balanced one, which enhances the best qualities of HD800 but smooths any defects or harshness;
I recently took a further step forward to improve the sound of this amplifier with a wonderful Valvo Sylvania 5931 Gold .
An astonished rectifier tube, practically the military version of the Sylvania 5U4.
In comparison with the previous Sylvania I had on board, the leap forward was remarkable!
In particular as far as control and balance are concerned in all frequencies, particularly detectable in the low, high and bandwidth extremes.
Should I use a single word to define it, I would call it granitic.
In comparison, the excellent previous combination (which I could have enjoyed for 10 years, don’t get me wrong!) seems to be more “hysteric” and less precise, losing ground in practically all parameters, to varying extents…
- Jensen + Sylvania 5931 Valvo : *****(**)
For this combination, I had to add not even one, but two extra stars!
Top neutrality, control and balance in all frequencies, especially towards the extremes.
Its sound is much less “pushed” in comparison with 5U4 Standard, much more natural and pleasant to listen to.
At the moment there is no challenge at all, this is THE rectifier for this amplifier!
TUBE ROLLING AND TIMBRE
I would like to add a note about this topic.
Apart from the rectifier, in this machine you can exchange the 5998 with 421A Western Electric (A militarized 5998, If you find them!), or you can replace the 6h23 with ECC88.
Lorenzo explained to me that, if it is normally possible to replace ECC88 with 6h23, the opposite is not always true.
This depends on the amount of power applied to these tubes, envisaged by the designer, and the 6h23 have much higher tolerance values.
In the model in question, the 6h23 are used approximately 60%, whereas the ECC88 would be used 80% at least, therefore there is still a little margin.
I would also like to add a quick note about the timbre.
Many in this forum certainly know, but it was a surprise for me and I would like to report to you what they explained to me the other day: sounds can also be heavily affected by the driver polarization!
In other words, it means that if you vary the amount of power supplied to the 6h23, in this case (you need to change the resistance value), you also vary the timbre of the amplifier.
I do not intend to do so in any way (you should need to know WHAT you are doing before trying), but I mentioned it because it lies within the framework of the flexibility of this amplifier, as well as all the tube amplifiers in general, and I thought it could be a further topic to discuss
CONCLUSIONS
As I have already said, behind this amplifier, almost humbly hidden, there is a plate with the name of the designer silk screened.
Transparency, transparency (it is not a repetition), dynamics, speed, focus, control, bandwidth, airiness, power, refined and researched components… It took a long time, but now I really have all I desired and even much, much more!
I am satisfied, very satisfied, I do not know what else I could ask for!
Forgive me for my enthusiasm, but it is my “new toy” and I really feel like a child who has just unwrapped a gift he has been asking for a long time!
Placing my feet back on the earth, I noticed that after a period of break-in, more than the 80 initial hours, it improved and opened more… Maybe after a few more hours it will reach its best, but I daresay that it is all a matter of details by now.
As I have already said, we were all struck at the versatility of this amplifier.
And I do not refer to its operating potential only, but also the remarkable differences which can be obtained by changing the abovementioned components: signal caps and the rectifying tube.
This factor, in my opinion, makes the amplifier very adaptable within the audio chain, and this is not something you should neglect!
The headphone double OUT is something I could never make do without, having tried it, whereas the 4 INs and the two OUTs really provide me with all the connections I need.
The Pre is an added value I really desired and it will be very useful when I replace my current Integrated Amp with a Final (or an Integrated one equipped with inner switching).
The double frame is an absolute must-have element.
The benefits of separating the power supply section and the amplification section are incomparable and should not underestimated, especially because, besides lowering weight and encumbrance of the amplifier to be placed on a piece of furniture, it offers the great advantage of a better control on vibrations, for the benefit of the whole system.
I have no particolar criticism.
As a matter of fact, I don’t know what to say, both because I cannot compare it with any other Amps of the same class (there is nothing like THE ultimate electronics!), and because my whole listening group could not detect any lack or defect in any test we performed. They had no criticism to put forward, especially considering the cost.
Now, I cannot say if the real class it belongs to is that of 1500€ (with a purchase group, the official price is 1800€), the price I paid, as I mentioned I could not find anything to compare it with… but for those who have had or listened to the previous EA headphone amplifier, I can say that, though they remain wonderful, they cannot compare!
It is based on almost one year of work for the designer and a long wait for us, but the time and work definitely paid off!
In the future, considering the positive experience with the signal cables, I would like to replace at least one couple of YARBO rhodium RCAs with WBT Nextgen silver ones and see what changes.
Certainly, the Mundorf would also have benefited from a much longer break-in and I would like to experiment and try the new Supreme Evo caps more in depth, the Jensen with silver reinforcements (if my bank accepts to grant me a loan…) or something similar…
FINAL NOTES:
Some people ask me about this product... Yeh, I am not a reseller and I know that on the website there is not any information about this product. This is because it is a CUSTOM product made only for a little group of people, BUT available on-demand writing directly to the manufacturer...
Anyway... last month I had the opportunity to visit the "Gran Galà dell'Alta Fedeltà" in Rho (close to Milan, Italy) and listening to the McIntosh MHA100 ... ehhh... what a big peace of hardware guys!
I listening to many different kind of music in HD file with my HD800 and there was a very nice experience!
Compared to EA it is hard to say, but I did not notice any remarcable difference, so my friends.
I know... different source, different conditions, no possibility to directly compared side by side, but we opportunity listen it the evening before, I can reasonably assure you that IF there was a difference it is really in details and we do not found it better in sound... and this a very nice surprise for me!
The cost is about 3 times (in Italy, anyway), but I suppose that a certain levels of quality it is all about your tastes and interface in your audio chain...
As you know very well, partially because you need to try the various combinations (and it is always quite hard), partially because I had fallen in love with the previous model (see here: http://www.ilgazeboaudiofilo.com/t23716-estro-armonico-otl-sennheiser-hd800), eventually I opted for OTL Amplifier by Estro Armonico.
I was taking my first few steps into the Audio world with a capital “A”, and I was literally freezed at what I could listen to in the weeks when they sent me their test unit to enable me to assess it. Up to the point that I ordered Lorenzo Betti and Massimiliano Fraboni a new Amplifier and made up a little purchase group to support them in the development phase.
The goal was to obtain a device similar to the original one from the point of view of the sound, keeping all its pluses, namely timbre, dynamics, transparency, speed, while correcting its imperfections and making it more versatile.
The only formal request was to improve a bit the punch for the headphones it would be used with, Sennheiser HD800, which was not impeccable in the model I had tested.
One year has passed and the new Amplifier is here beside me, its bulbs as warm as little ovens, as it waits for me to push “play” on my CD player.
Let’s see what has changed from the original device I tested last year…
TECHNICAL SPECIFICATIONS:
POWER: 3.5 W for 600 Ohm / 1.75 W for 300 Ohm
GAIN: 15 db
S/N RATIO: over 90 db
FREQUENCY RESPONSE: 5-100,00 Hz
SENSITIVITY: 150 mV
POWER SUPPLY UNIT SIZE: 22 L z 30 D x 13 H, 11 kg
AMPLIFIER SIZE: 32 l x 30 D x 5.5 H, 4.6 kg
TUBES: pre 2x 6H23 (or ECC88), final 2x 5998 (or 421A WE), rectifier 1x 5U4/5931 (GE / Sylvania / Svetlana)
SELLING PRICE: € 1800
http://www.estroarmonicoaudio.com
https://www.facebook.com/Estro-Armonico-492197340828823/
MANIFACTURE:
It is a professional product, home-designed and manually assembled.
This is more than clear, despite they have paid a lot of attention to its appearance.
However, this is not a defect, but should be seen as a precise feature, characterising each electronic device manufactured by this company.
Each detail has been taken care by the designer personally, and this ensures greater quality than any industrially manufactured product.
The rest is just aesthetic details.
Paying a visit to the laboratory is like taking a real journey through time.
To a different age, when we had the time to stop and think about things, rather than just “do them”…
Let’s start from the frame.
From a technical point of view, the frame (original project) is made of non-magnetic AISI 316 stainless steel of thickness 20/10 3 mm for the heat, with 3 cm whole wood lateral elements, 2mm aluminium grid at the bottom and 3 feets. It is connected to the power supply by a 1.5 m cable with apowercon connector.
For the power supply, the Nordlys frame, another EA project, was used. It is fully made of 5mm aluminium, with 4 feets and powercon power connections (IEC on demand).
The first thing that draws your attention is its size! And in this respects, photos cannot give you an idea.
Both the head and the power supply unit are twice as big as those in the little system I previously tested. In particular, the power supply unit is titanic!
In other words, you can see and feel its 11 kg, entirely!
The generated power is 350VA and it is very heavy, but all in all it is more than acceptable and separating the system into two units makes sense.
Inside Components.
I am not knowledgeable in electronics and I cannot assess the quality of each single component, nor can I understand the planning logic behind the choice of the components, but I can tell you what the results of these choices are!
The project is very similar to the original one, therefore, initially the idea was simply to improve the quality of components, while keeping the project unaltered.
In any case, we were focusing on the quality, taking into consideration high-quality military and industrial components whose costs would be affordable from the point of view of the final price.
As the project developed and the first few tests were being carried out, Lorenzo took a passion in it and started to realise that it
was possible, with some modifications, simplify it even more and create something remarkably better.
From that moment, a long period of experiments and search for the best components started, until they were selected, involving even Lorenzo’s persona stock of items he had carefully selected through the years.
Needless to say, the cabling is totally in air, with 60/40 Copper/Silver solid core cables.
This cables are normally used in the aeronautic, airspace and navy sectors, and are the standard of choice for EA.
Transformer and inductance were made manually on the basis of the specification, using 4% iron-silica grain-oriented plates.
Finally, they were dipped into oil (double passage) and the transformer was “tarred” with what looks like anti-drumming paint and assembled on the power supply unit on rubber pins. All this resulted in great improvements of the vibrations
One specification: when I say “military components”, I do not refer to consumer components produced for military purposes and freely available on the market.
I mean real military components, disassembled, one by one, from US and USSR instruments not used anymore, chosed and bought in stocks directly on place! I worked as a radar operator on
military ships for three years… we are speaking about something completely different and made for a single purpose: to always work with those specifications, resisting everything without breaking (at least, that is the idea). It is not consumer products and it does make a difference, believe me!
The same holds true for the industrial components used.
Here, the quality standard is very high too and the components come from old scientific devices. Other things, obviously, are consumer products, but they are always high quality ones (e.g. alps black beauty potentiometer, Mundofr/Jensen condensers).
Here is a list of what is inside (and outside) the two boxes:
4 RCA NEUTRIK IN (GERMANY YARBO made of Rhodium / custom Silver upon request)
2 RCA NEUTRIK OUT (GERMANY YARBO made of Rhodium / custom Silver upon request)
1 FEME IN commuter with gold contacts
2 headphone OUT with silver contacts (Neutrik Nj3FP6C-BAG)
- PRE-AMPLI circuits, with commuter
- Standard Powercon 20A power supply connector (with cable included) / IEC upon request
1 ALPS RK40 Black Beauty logarithmic potentiometer
2 Mundorf Supreme OUT Caps Silver/Oil/Jensen with Copper reinforcements – 1uF
2 Switching Electrolytic caps
2 Tubes 5998
2 Pre tubes 6H23 (replaceable with ECC88)
1 Rectifying tube 5U4 (GE / Sylvania / Svetlana)
1 Stainless steel volume knob, equivalent to Nordlys
- 350VA separate power supply unit, with 4% iron-silica grain-oriented plates handmade manufactured
- Kiwame/Alle Bradley resistances
- DALE Armored cathode resistances complying with military norms (25W/1% tolerance)
- Air cableing with 60/40 Copper/Silver thread coated with Teflon
- Non-magnetic AISI 316 stainless steel AMPLIFIER frame of thickness 20/10 with upper plate bearing a logo, 3 removable feets and wood lateral pieces
- Aluminium Nordlys POWER SUPPLY frame of large thickness and stainless steel plate, main switch
SETUP
The setup used for the tests is the same as all my setups, with some minimal adds:
Sounds used:
My favourite genres range from rock to jazz, blues, without neglecting some electronic and experimental contaminations.
The CDs/SACDs used for this test were the same already as in the review of the previous model, plus a few high-resolution files, namely:
Pink Floyd (The Wall / Dark Side of the Moon, CD remasterised in 2011 by James Guthrie), BB King (Live at the Apollo, Verve), Dire Straits (Brothers in Arms, SACD), Doug Macleod (There's a Time, HDCD), The Ultimate Chesky Demostration Disk HD Tracks ( http://chesky.com/album/ultimate-demonstration-disc-ud95 ).
For the electronic part:
- Cambridge Audio BD751 Universal Player
http://www.ultrahighendreview.com/cambridge-audio-azur-751bd-universal-blu-ray-player/
- Oppo 105 Universal Player
http://www.tnt-audio.com/sorgenti/oppo_bdp105.html
- FiiO X5 (1st Jan) digital player
http://www.head-fi.org/products/fiio-x5-high-res-portable-music-player/reviews
- EstroArmonico OTL SIGNATURE headphones amplifier
http://www.estroarmonicoaudio.it/
- Amplificatore portatile Fiio E12 DIY Limited
http://www.head-fi.org/products/fiio-e12-diy-limited-edition-portable-amp-headphone-slim-amplifier
- Sennheiser HD800 headphones
http://www.stereo-head.it/2013/07/cuffie-sennheiser-hd800-recensione/
- Sennheiser HD650 headphones
http://www.tnt-audio.com/casse/headphones_test.html
Final details:
- Furutech single thread silver signal wires (home-built – 19AWG 0.9 mm single-thread, protected by a copper insulation and PVC protection, V&M connectors)
http://www.furutech.com/2013/01/29/1496/
http://www.audioselection.it/product.php~idx~~~1924~~V+_+M+CS1032~.html
- Mundorf signal cables (home-built – 4 silver +1% gold 24AWG single wires, 0.5 mm each, intertwined without protection, V&M connectors)
http://www.audioselection.it/product.php~idx~~~328~~MUNDORF+SGW+105~.html
http://www.audioselection.it/product.php~idx~~~1924~~V+_+M+CS1032~.html
- Mundorf signal cable (home built – 4 silver +1% gold 24AWG single wires, 0.5 mm each, intertwined with double protection, WBT Nextgen connectors)
http://www.audioselection.it/product.php~idx~~~328~~MUNDORF+SGW+105~.html
http://www.wbtusa.com/pages/0110ags.html
- Ebony feets with zircon spheres V&M SYMBIO P1-33 for uncoupling electronics
http://www.audioselection.it/product.php~idx~~~1742~~V_M+SYMBIO+P1_33~.html
- Home-build feets, based on the V&B model
(oaken frame, silicon nitride 9.5 mm spheres)
http://www.rgpballs.com/it/prodotti/SFERE/SCELTA-RAPIDA/CERAMICA/sfere-in-nitruro-di-silicio-si3n4
What a beautiful surprise! The best setup was found to be rather different from what I found for the previous model.
Let us see why:
Source.
Before the best source was the Oppo player, now it is the Cambridge one.
The pleasant news is that, besides being the player I have at home, the Cambridge one is also a previous generation compared to the Oppo. The sound is simply more natural, I don’t know how to define the concept better. Besides the analytical nature of the Oppo sound, the musicality is simply better.
Moreover, it was simpler to interface the Cambridge player, this time.
With the previous tests (old EA model), after connecting the Oppo and noticing that the sound improved with a proper adjustment of the signal outgoing volume, we had the impression that the default Cambridge fixed outgoing volume was too loud, thus compromising my listening experience.
The feel I had was that of a bloated and less controlled sound than the Oppo.
Now this sensation has disappeared completely, this proves how Cambridge performed well with this player!
Signal cables.
The best wire is still the home-built Mundorf one, here in its double protected version with WBT Nextgen connectors. In comparison with the previous wire, we noticed a better focus on the instruments and a remarkably better scene, therefore this is our reference signal wire.
Feets.
The home-built feets proved to be better than the Symbio ones, I really didn’t expect that!
In this setup, the Symbio ones tend to get dry a lot, whereas the oaken ones remain unaltered, thus simply improving what can be improved… excellent, at a very low price (almost nothing), they are a bargain, I’ll haste to build some more!!!
Evidently, the older EA model's power supply unit benefited from this detail, whereas here it is not necessary or is even harmful… I would like to point out the enhanced transparency and dynamic excursion, whereas my friends pointed out the rhodium connectors… never mind
Even under the CD player, the new feets perform very well.
However, here I had the impression that the enhanced impact is due to the vibration dissipation system due to the sphers, rather than the wood.
For the details of the home-building of these feets and the principles on the basis of which the various materials work and are selected, you may read and take part in this (italian, sorry) thread:
http://www.ilgazeboaudiofilo.com/t27371-piedini-a-sfere-oscillanti-diy
Rectifying tubes and caps combo.
A critical part of this test, and the one which required the longest time for the final adjustments.
As you certainly know better than I do (I have only just learnt it), the sound of a tube system like this is deeply affected by the performances of some components more than others.
Leaving alone the pre and final tubes for a second (we will not deal with them), I am going to discuss the signal caps and the power supply rectifying tube.
The right combination for “your” sound in this amplifier is to be looked for, by investigating the proper combination between these two critical components.
Originally, some Mundorf Supreme Silver Oil elements were used and the tube which, in theory, would guarantee the greatest power supply, namely General Electric (in any case, the difference with the others is minimal).
It was supposed to be the winning choice, but something in the sound was not convincing me, so I decided to test some more combinations.
I talked about it with Lorenzo Betti and Massimiliano Fraboni, and we eventually decided to carry out a day of wide ranging tests in their laboratories.
On the table, we had everything we needed: the previous amplifier I originally tested and the new one in two versions, one with Mundorf caps (about 90 hours of testing), the other with Jensen caps with copper reinforcements (about 80 hours of testing).
This is what I initially found (grades from 1 to 5 stars, with reference to the initial setting, which is the ideal one in my opinion):
- Mundorf + GE: *
The first combination I tried at home, which could not convince me!
Too dry and sparkly for me, the instruments sound fine but the voices get harsher;
- Mundorf + Sylvania : **
As for the general sweetness, it is a bit better, but it is still a bit too sparkly for my tastes;
- Mundorf + Svetlana : ****
A further improvement, sweeter and rounder sound. It is a matter of personal tastes;
- Jensen + GE : **
A strange combination, what you gain with the caps, you lose with the rectifying tube.
- * Jensen + Sylvania : ****
A good combo, nothing to remark, except that the choice is due to your tastes; I liked it;
- * Jensen + Svetlana : *****
Full sound and rich of harmonics.
At the beginning of this lab test, as for my personal taste, it was the perfect combination, with all kinds of music, it can compete with the previous one and the Mundorf-Svetlana combination;
I believe the list above is self-explanatory, you should not have any doubts about what I brought back home!
I must admit I was impressed at the remarkable differences I found between all these tests! I spent the whole day changing heads, power supply units, tubes, caps…
At the end of the day I was exhausted, but I have to say that it was really worth it!
(Thanks Lorenzo and Massimiliano for your patience and support!
LISTENING
The most important parameter of all. Eventually, what does this amplifier sound like?
Very, very, very WELL indeed! We were all favourably impressed at the results you can achieve with this amplifier, as well as its versatility.
Svetlana proved to be a marvellous valve, which I can describe using only one word: MUSICAL!
The GE → Sylvania → Svetlana shift showed an improvement in this respect.
With GE, it seems that you deal with a solid state, in the cold and sharp meaning of the term. Progressively, for the other two, this situation improves remarkably and the harmonics start to reappear in a superb way!
The Mundorf caps, instead, did not fully satisfy me, it was very hard for me to understand what I was really listening to and why…
I mean, I expected a very different sound. They are hyper-analytic as the best modern solid state, maybe even more than the Jensen ones, but also much more brilliant than I expected!
Combined with the GE, indeed, you cannot listen to them for more than 15 minutes without feeling tired.
Instruments are perfect, whereas voices are as sharp as razors… When I listened to this combination for the first time, I didn’t know what to think about this slightly metal veil which seemed to lie on everything.
Analyticity, monstrous transparence, details, speed as the very best solid state… it was all there, but the listening emotion which the previous model had given me was missing!
In order to be sure about the results, the tests were carried out both with the electronic components listed in this review and with a Lector CDP 7 TL Tube.
Unfortunately, not even such a valve and famously sweet and well-sounding source as this one could help, and this parameter did not change at all.
The replacement of the rectifying tube from GE to Svetlana changed everything, everything became as different as cheese from chalk, and everything started sounding great again, like magic!
So why should you choose Jensen rather than Mundorf?
Probably, it is only a matter of personal tastes.
By listening to them one after the other, with the same reference musical pieces, I realized that I preferred a less analytical and more touching, velvety sound.
Moreover, the Jensen caps made the HD800 more tolerant to sibilating sounds than the Mundorf ones.
Not less transparent, do not get me wrong!
In this respect, we are dealing with absolute reference levels!
In some classical music recordings (CDs) you can hear a moped in the distance outside the studio and in There’s a Time by Doug Macleod (HDCD) you can hear a chair creaking and a (single) cricket sing for a few instants at different times during a couple of pieces (this makes me think it was an outdoor evening recording). In other recordings you can hear the musicians breathing into their instruments and pressing the keys of their saxes and trumpets, in some you can even hear it on the piano… Impressive!
As for the dynamics, very close to the theoretical limits, “you can hear it all”, as Lorenzo Betti stated.
Bad recordings, instead, remain bad… but in any case, who wants to listen to them?
Anyway, after all they both sounded great and it was only a matter of personal tastes!
The final definition I can give is that with the Mundorf caps you have the impression that it is a solid state, whereas with the Jensen ones everything is about tubes. Both are top quality!
I felt particularly enlightened by the Demo Chesky HD tracks.
For those who haven’t had a chance to listen to them, all the recordings in question have a guiding voice which tells us where, how and when they were recorded, why they have been proposed, what they intend to highlight with each musical piece (dynamics, transient, fire, etc.) and what should reach your headphones.
I must admit I had a lot of fun listening to this Demo! Besides the pieces proposed, all wonderful, I did not find it difficult at all to immediately identify the feature which each piece meant to highlight, this obviously proves the high quality of the whole listening system!
All the instrument sounded correct, well focused and distinguishable.
The planes seemed correct to me, just like the tridimensional space of the stage.
In one of the pieces, for instance, the guiding voice told us that on the stage there was just one saxophone player at a distance of 3 metres from the microphone and gave us all the spatial references about the side and back walls, the size of the studio, etc. It is wonderful to realize, without any efforts, that the sax is really there, at the same distance specified, both from you and from the microphone!
And you can easily distinguish the notes from the pressure of the keys and the musician’s breath…
Same feelings for all the other musical pieces… I believe this is the best example you can give to properly provide information about this amplifier!
Comparison with the previous OTL EA. (http://www.ilgazeboaudiofilo.com/t23716-estro-armonico-otl-sennheiser-hd800).
On the back side of the model I took home there is a suitably made plate, bearing the signature of the designer silk screened. THAT’S ALL. No further word should be necessary.
When you speak about it, Lorenzo’s voice changes completely and you can feel the passion and pleasure he poured in this product. In his and Massimiliano’s opinion, this is the most transparent and best sounding headphone amplifier ever produced in their laboratories.
I have only one definition: a wire with gain!
Or in any case, the closest thing to this definition which I have ever had a chanceto listen to!
A comparison with the previous model simply makes no sense.
I thought it was a wonderful Amp (and indeed it is!) and that not much could be improved, but I was very wrong because, in comparison with the new one, it sounds like a portable battery radio!
To me, this is absolutely incredible! I had the impression that it would sound better, but I could have never expected such a huge gap!
Comparison between HD800 and HD650.
The choice to have two headphone connectors proved to be absolutely right!
The convenience of not having to continuously unplug a set of headphones to put on another one, pausing the recording and then going back to the precise point you were listening to… it is priceless!
Simultaneous listening in this way was so incredible from this point of view, and we could verify that this amplifier did not betray us at all, managing the HD800 in a perfect way and effortlessly at any volume.
Despite this, it was a very, very difficult comparison.
If the differences were evident before, now they have become very slight.
You can immediately sense the superiority of HD800, but the 650 model is not the headphones it was before this amplifier, now it Sounds (with a capital “S”) really and really good!
And this was a big surprise, since this amplifier was tailored to the HD800 (headphones which stayed in the laboratory for all the time necessary), therefore…
Now it is much more open, bright andbetter performing in the low part.
Again about Doug Macloud, the 650 was even preferable for some musical pieces, due to its “old-style” settings, more suitable for this genre than its elder sister.
And what about the HD800? It has grown stronger and found fantastic bass, which we were blissfully unaware it could have! Really, you still do not know what bass these headphones can have if they are managed properly! Powerful, very deep, but stable and controlled, never aggressive.
The loud and very loud tones are all there, sweet and never sharp or harsh.
The sibilating sounds are only present if they are present in the recordings (and if their quality is good, they will never annoy you!
)The average range is really remarkable, a jewel… I can only tell you that the voices are REAL, ALIVE.
With both headphones, both male and female voices are such as to intimately touch you!
If the HD800 are finally able to reach their full potential, perhaps the real miracle is the performance with the HD650 ones, in certain respects very close to their elder sister.
I am seriously thinking about buying one…
At this point, I am curious to try some more headphones, HiFi Man, Audeze…
If my impression is correct, this amplifier can manage everything well…
A COUPLE OF MONTHS LATER
(*) IMPORTANT NOTE: at the end of a long testing period, about a couple of months after the first few listening sessions, I performed a new series of tests by replacing Svetlana with Sylvania. I did so because the sounds of the caps has changed in time and I wanted to check whether my initial feelings still held true.
And I had a big surprise!
The situation diametrically changed in favour of Sylvania, clearly better than Svetlana at the end of the break-in!
I thought I had found the perfect combination, but I was definitely wrong, there was something much, much better!
Airy, well-defined, with an equally deep but much more stable basses, crystal-clear and never sharp (and possibly even more refined and sweeter than before) loud and very loud sounds.
Once again, very airy instruments and a huge soundstage!
In comparison, Svetlana now sounds close and “swollen”.
It is still a good tube, but there is no comparison at all… I would assess them 6 and 10, respectively, in a 0-10 scale, that should be clear…
Evidently, the exuberance and strength of Svetlana somehow made up for the lacks I failed to notice immediately.
After all, experience can only be achieve with time… I am taking notes about everything, some day I will go through it again…
At this point, I would like to review the table above and make the following modifications:
- Jensen + Svetlana : ****
Rich sound, full of harmonics.
It is an excellent combination, with a great push, especially in the low tones, and compatible with any musical genre.
However, I would recommend listening very well once after a full break-in, since the sound might seem a bit closed and “swollen”, especially if compared with that of more “educated” tubes like Sylvania;
- Jensen + Sylvania
(5U4 standard) : *****
After the end of the tests, it proved to be the perfect combination!
A lot of air between the instruments, a huge soundstage, deep and very controlled low tones, crystal-clear and never sharp high and very high tones.
A valve which contributes to a very relaxing sound and, more importantly, a very well balanced one, which enhances the best qualities of HD800 but smooths any defects or harshness;
I recently took a further step forward to improve the sound of this amplifier with a wonderful Valvo Sylvania 5931 Gold .
An astonished rectifier tube, practically the military version of the Sylvania 5U4.
In comparison with the previous Sylvania I had on board, the leap forward was remarkable!
In particular as far as control and balance are concerned in all frequencies, particularly detectable in the low, high and bandwidth extremes.
Should I use a single word to define it, I would call it granitic.
In comparison, the excellent previous combination (which I could have enjoyed for 10 years, don’t get me wrong!) seems to be more “hysteric” and less precise, losing ground in practically all parameters, to varying extents…
- Jensen + Sylvania 5931 Valvo : *****(**)
For this combination, I had to add not even one, but two extra stars!
Top neutrality, control and balance in all frequencies, especially towards the extremes.
Its sound is much less “pushed” in comparison with 5U4 Standard, much more natural and pleasant to listen to.
At the moment there is no challenge at all, this is THE rectifier for this amplifier!
TUBE ROLLING AND TIMBRE
I would like to add a note about this topic.
Apart from the rectifier, in this machine you can exchange the 5998 with 421A Western Electric (A militarized 5998, If you find them!), or you can replace the 6h23 with ECC88.
Lorenzo explained to me that, if it is normally possible to replace ECC88 with 6h23, the opposite is not always true.
This depends on the amount of power applied to these tubes, envisaged by the designer, and the 6h23 have much higher tolerance values.
In the model in question, the 6h23 are used approximately 60%, whereas the ECC88 would be used 80% at least, therefore there is still a little margin.
I would also like to add a quick note about the timbre.
Many in this forum certainly know, but it was a surprise for me and I would like to report to you what they explained to me the other day: sounds can also be heavily affected by the driver polarization!
In other words, it means that if you vary the amount of power supplied to the 6h23, in this case (you need to change the resistance value), you also vary the timbre of the amplifier.
I do not intend to do so in any way (you should need to know WHAT you are doing before trying), but I mentioned it because it lies within the framework of the flexibility of this amplifier, as well as all the tube amplifiers in general, and I thought it could be a further topic to discuss
CONCLUSIONS
As I have already said, behind this amplifier, almost humbly hidden, there is a plate with the name of the designer silk screened.
Transparency, transparency (it is not a repetition), dynamics, speed, focus, control, bandwidth, airiness, power, refined and researched components… It took a long time, but now I really have all I desired and even much, much more!
I am satisfied, very satisfied, I do not know what else I could ask for!
Forgive me for my enthusiasm, but it is my “new toy” and I really feel like a child who has just unwrapped a gift he has been asking for a long time!
Placing my feet back on the earth, I noticed that after a period of break-in, more than the 80 initial hours, it improved and opened more… Maybe after a few more hours it will reach its best, but I daresay that it is all a matter of details by now.
As I have already said, we were all struck at the versatility of this amplifier.
And I do not refer to its operating potential only, but also the remarkable differences which can be obtained by changing the abovementioned components: signal caps and the rectifying tube.
This factor, in my opinion, makes the amplifier very adaptable within the audio chain, and this is not something you should neglect!
The headphone double OUT is something I could never make do without, having tried it, whereas the 4 INs and the two OUTs really provide me with all the connections I need.
The Pre is an added value I really desired and it will be very useful when I replace my current Integrated Amp with a Final (or an Integrated one equipped with inner switching).
The double frame is an absolute must-have element.
The benefits of separating the power supply section and the amplification section are incomparable and should not underestimated, especially because, besides lowering weight and encumbrance of the amplifier to be placed on a piece of furniture, it offers the great advantage of a better control on vibrations, for the benefit of the whole system.
I have no particolar criticism.
As a matter of fact, I don’t know what to say, both because I cannot compare it with any other Amps of the same class (there is nothing like THE ultimate electronics!), and because my whole listening group could not detect any lack or defect in any test we performed. They had no criticism to put forward, especially considering the cost.
Now, I cannot say if the real class it belongs to is that of 1500€ (with a purchase group, the official price is 1800€), the price I paid, as I mentioned I could not find anything to compare it with… but for those who have had or listened to the previous EA headphone amplifier, I can say that, though they remain wonderful, they cannot compare!
It is based on almost one year of work for the designer and a long wait for us, but the time and work definitely paid off!
In the future, considering the positive experience with the signal cables, I would like to replace at least one couple of YARBO rhodium RCAs with WBT Nextgen silver ones and see what changes.
Certainly, the Mundorf would also have benefited from a much longer break-in and I would like to experiment and try the new Supreme Evo caps more in depth, the Jensen with silver reinforcements (if my bank accepts to grant me a loan…) or something similar…
FINAL NOTES:
Some people ask me about this product... Yeh, I am not a reseller and I know that on the website there is not any information about this product. This is because it is a CUSTOM product made only for a little group of people, BUT available on-demand writing directly to the manufacturer...
Anyway... last month I had the opportunity to visit the "Gran Galà dell'Alta Fedeltà" in Rho (close to Milan, Italy) and listening to the McIntosh MHA100 ... ehhh... what a big peace of hardware guys!
I listening to many different kind of music in HD file with my HD800 and there was a very nice experience!
Compared to EA it is hard to say, but I did not notice any remarcable difference, so my friends.
I know... different source, different conditions, no possibility to directly compared side by side, but we opportunity listen it the evening before, I can reasonably assure you that IF there was a difference it is really in details and we do not found it better in sound... and this a very nice surprise for me!
The cost is about 3 times (in Italy, anyway), but I suppose that a certain levels of quality it is all about your tastes and interface in your audio chain...
