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Maestral´s Had-AudioLab from Croatia Europe
Jun 1, 2014 at 8:47 AM Post #46 of 58
Dears,
 
first of all some pictures:
I had the chance to listen the Maestral Zephyr with some friends. We had three units and two top cd-player from Italian manufacturer (Lector and Gold Note). Also we had an headphone amplifier with c3m/f2a tube and an ibrid italian DIY amp (Lightning). We have used for k1000 and stax an Italian custom 300b amp with proper output transformer (Woo audio)
 
As headphones: 
 
Grado Sr80/R1
Sennheiser 430/565/600/650 with various cables
Bayerdynamic dt48
Audeze LCD-3
Hifiman HE500
Stax 404/SigmaPro/407/507/007/009
AKG 501/340/K1000
 
 

 
 

 
I will not describe differences among headphones because there is already a lot of information and I will focus on the Zephyr amp.
Also I will not cover in detail the sonic characteristics because it is not needed in my opinion.
 
Simply put the Zephyr with 2a3 is the best DYNAMIC headphone amp that we have had the pleasure to listen. With Sennheiser 565 and 600 the difference from the LCD-3 was not so far. Sure the LCD-3 is BETTER on everything but in this configuration not far...! 
With the grades everything is right and never strident or fatiguing.
This is really an accomplishment because something that work AT THE TOP both with Sennheiser and Grado is quite unique.
Also with others headphone (Bayerdynamic and aka) the performance was perfect and only a matter of fine tuning (tube, different cables and cd-player).
 
You easily loose yourself in the music and this is the only thing that matter.
 
Talking about planar headphones, the Zephyr drove them equally good. I'm not really a fan of planar presentation but objectively music reproduction was on par with dynamic headphone and at the end is only a matter of taste.
 
Finally ELS: for me and one of my friend there wasn't enough volume this because of the 2a3 that is not good in DHT for ELS driving. Instead for the third friend it was good enough (also because he has the MKIII version with better transformer). 
 
For this reason Drazen has built a more powerful version of the Zephyr amp with 807a tube. These are more suited also for ELS driving and if they reach the same quality as dynamic and planar headphone we have quite an unique amp!!
 
So in the end the Zephyr with 2a3 will be modified to be only a dynamic and planar headphone amp, fine tuned for these headphones. Then there will be the Zephyr 807a also for ELS. And soon I will review a fully dedicated ELS amp from Had-Audiolab.
 
So, sorry for a not so detailed review but when everything is right, musical, dynamic with natural tone and timbre with every headphone we tested what should I need to add !??? :)
 
Marco
 
Jun 1, 2014 at 9:49 AM Post #47 of 58
Nice one Marco, too bad it didn't work quite well with the electrostatic.
Hopefully the one that Drazen build for me with 807 will solve the issue and rocked the 3 of them 
L3000.gif

 
Nevertheless, 2 out of 3 is great for the price point.
Quote:
cappellano said:
  Dears,
 
first of all some pictures:
I had the chance to listen the Maestral Zephyr with some friends. We had three units and two top cd-player from Italian manufacturer (Lector and Gold Note). Also we had an headphone amplifier with c3m/f2a tube and an ibrid italian DIY amp (Lightning). We have used for k1000 and stax an Italian custom 300b amp with proper output transformer (Woo audio)
 
As headphones: 
 
Grado Sr80/R1
Sennheiser 430/565/600/650 with various cables
Bayerdynamic dt48
Audeze LCD-3
Hifiman HE500
Stax 404/SigmaPro/407/507/007/009
AKG 501/340/K1000
 
 

 
 

 
I will not describe differences among headphones because there is already a lot of information and I will focus on the Zephyr amp.
Also I will not cover in detail the sonic characteristics because it is not needed in my opinion.
 
Simply put the Zephyr with 2a3 is the best DYNAMIC headphone amp that we have had the pleasure to listen. With Sennheiser 565 and 600 the difference from the LCD-3 was not so far. Sure the LCD-3 is BETTER on everything but in this configuration not far...! 
With the grades everything is right and never strident or fatiguing.
This is really an accomplishment because something that work AT THE TOP both with Sennheiser and Grado is quite unique.
Also with others headphone (Bayerdynamic and aka) the performance was perfect and only a matter of fine tuning (tube, different cables and cd-player).
 
You easily loose yourself in the music and this is the only thing that matter.
 
Talking about planar headphones, the Zephyr drove them equally good. I'm not really a fan of planar presentation but objectively music reproduction was on par with dynamic headphone and at the end is only a matter of taste.
 
Finally ELS: for me and one of my friend there wasn't enough volume this because of the 2a3 that is not good in DHT for ELS driving. Instead for the third friend it was good enough (also because he has the MKIII version with better transformer). 
 
For this reason Drazen has built a more powerful version of the Zephyr amp with 807a tube. These are more suited also for ELS driving and if they reach the same quality as dynamic and planar headphone we have quite an unique amp!!
 
So in the end the Zephyr with 2a3 will be modified to be only a dynamic and planar headphone amp, fine tuned for these headphones. Then there will be the Zephyr 807a also for ELS. And soon I will review a fully dedicated ELS amp from Had-Audiolab.
 
So, sorry for a not so detailed review but when everything is right, musical, dynamic with natural tone and timbre with every headphone we tested what should I need to add !??? :)
 
Marco
Click to expand...

 
Jun 1, 2014 at 3:53 PM Post #48 of 58
I'm sure that it will be!!! Actually I could order one myself in the near future because Drazen will revert the 2a3 for only planar and dynamic!!
He know how to make electronics really sing!
 
Jul 5, 2014 at 9:37 AM Post #49 of 58
Hello,
I'm the "third man", the one with the MkII Zephyr......... I can confirm Marco's words, with a lettle difference about ELS headphones.
 
Without a doubt the Zephyr is the best amplifier for dynamic headphones I’ve heard in 40 years. The listening quality with Sennheiser, AKG and Grado is spectacular, as not to regret anything ... We have rediscovered the first class of old headphones like the HD-565, HD-430, K340, RS-1, capable of giving true emotions. The silence of the unit raise from very good to excellent, depending on the headphones. The loudest are the Grado RS-1 and Sennheiser HD-565, but much depends on the quality of the final tubes 2A3.
 
Listening with planar headphones is very good (especially with theHhifiMan), but not at the same level of dynamic headphones. In this case it is “only” an excellent amp! Everything sounds at the highest level, but lacks a little bit of magic.
 
Listening the K1000, from the speaker terminals, the sound is very good in the midrange and upper-middle, but a little “poor of impact” in the low range.
 
About ELS, the use of electrostatic headphones is limited to genres with low dynamic. Small group jazz and classical chamber music sound very, very nice, as long as you do not overboost with the volume. But if you need dynamic, 2A3 drives fast in crisis, with audible distortion. Maybe a 2A3 push-pull…
 
Well, a very interesting experience!!!
 
Giorgio - Italy
 
Jul 5, 2014 at 2:57 PM Post #50 of 58
Returning to Maestral amplifiers, I recently got to try the model for electrostatic headphones, Maestral 4Stax.
 


This is an OTL amplifier, with 6N7 power tubes, 6SN7 driver tube and 6X5 rectifier tube. The amplifier can also be used as preamplifier (input 1) and is equipped with a gain selector (0/-6 dB), useful to drive sources with different output levels.

I tested the amplifier with my Stax 009, comparing it with my amp for Stax, really a superb amplifier:

http://www.megahertzaudio.it/guerra.htm

Well, I haven't had much time to spend with the amplifier, but I think I have understood the sonic potential. The test was made with my 009 Stax.
From a sonic point of view the amplifier has a warm tone with excellent bass and mid-bass, deep, present and articulate. The yield is never regret a dynamic headphones, a very, very positive sensation. Even the mid-range is very well balanced and real, with well-designed male voices and transparent and smooth female voices, with no sign of bitterness. The top end, however, it is far enough back and with a not always adequate detail for the class of electrostatic headphones. Maybe a little roll-off, maybe a little poor detail ... Poor in comparison with the treble sound that the Zephyr shows with Stax.

This characteristic of the high range also affects the 3D of the amplifier, which appears a little closed, with no breath and airiness, negative characteristic that Stax show dramatically. The scene looks compressed compared to the Zephyr, confining all the sound inside of the head. I thought it was the fault of the valves, so I bought valves of good quality:
6N7 RCA matt finish, 6X5GT Brimar and Fivre and 6SN7 RCA.

Things have improved a little, but not as I expected. It almost seems like the kind of sound of the amplifier depends upon a design choice rather than materials (poor valves).

In the next days I've changed the rectifier tube, with a beautiful Fivre 6X5GT. Well, the Fivre 6X5GT was a REAL improvement for the Maestral. Great sound, really. Not great space, but the general level jumps ahead!

Finally, just in these days, I've decided to change the driver too. Rummaging in the closet of the valves I found a 1950's Sylvania 6SN7GTW, that I tried instead of the RCA and with the 6X5 Fivre and Tung-Sol metal base.

Well, I personally think that the change of the rectifier modifies the sound of the Maestral more than the driver in terms of timbre, but the change of driver is essential to open the scene.

Now, finally, the Maestral sounds like I wanted in terms of three-dimensionality and detail, with a really nice sound. The problem is the cost of the tubes................ :frowning2:

 

If Drazen will be able to change something in the circuit, to reduce the need for NOS expensive tubes, the amplifier will be really a high level one!!!!

 

Thanks to Drazen for the test!

 

Giorgio









 
Jul 6, 2014 at 3:00 PM Post #51 of 58
This one is more interesting to me: http://www.had-audiolab.com/products/power/zephyr-headamps-2a3-45
 
Jul 8, 2014 at 7:34 AM Post #54 of 58
edmond dantes said:
  Returning to Maestral amplifiers, I recently got to try the model for electrostatic headphones, Maestral 4Stax.
 


This is an OTL amplifier, with 6N7 power tubes, 6SN7 driver tube and 6X5 rectifier tube. The amplifier can also be used as preamplifier (input 1) and is equipped with a gain selector (0/-6 dB), useful to drive sources with different output levels.

I tested the amplifier with my Stax 009, comparing it with my amp for Stax, really a superb amplifier:

http://www.megahertzaudio.it/guerra.htm

Well, I haven't had much time to spend with the amplifier, but I think I have understood the sonic potential. The test was made with my 009 Stax.
From a sonic point of view the amplifier has a warm tone with excellent bass and mid-bass, deep, present and articulate. The yield is never regret a dynamic headphones, a very, very positive sensation. Even the mid-range is very well balanced and real, with well-designed male voices and transparent and smooth female voices, with no sign of bitterness. The top end, however, it is far enough back and with a not always adequate detail for the class of electrostatic headphones. Maybe a little roll-off, maybe a little poor detail ... Poor in comparison with the treble sound that the Zephyr shows with Stax.

This characteristic of the high range also affects the 3D of the amplifier, which appears a little closed, with no breath and airiness, negative characteristic that Stax show dramatically. The scene looks compressed compared to the Zephyr, confining all the sound inside of the head. I thought it was the fault of the valves, so I bought valves of good quality:
6N7 RCA matt finish, 6X5GT Brimar and Fivre and 6SN7 RCA.

Things have improved a little, but not as I expected. It almost seems like the kind of sound of the amplifier depends upon a design choice rather than materials (poor valves).

In the next days I've changed the rectifier tube, with a beautiful Fivre 6X5GT. Well, the Fivre 6X5GT was a REAL improvement for the Maestral. Great sound, really. Not great space, but the general level jumps ahead!

Finally, just in these days, I've decided to change the driver too. Rummaging in the closet of the valves I found a 1950's Sylvania 6SN7GTW, that I tried instead of the RCA and with the 6X5 Fivre and Tung-Sol metal base.

Well, I personally think that the change of the rectifier modifies the sound of the Maestral more than the driver in terms of timbre, but the change of driver is essential to open the scene.

Now, finally, the Maestral sounds like I wanted in terms of three-dimensionality and detail, with a really nice sound. The problem is the cost of the tubes................ :frowning2:

 

If Drazen will be able to change something in the circuit, to reduce the need for NOS expensive tubes, the amplifier will be really a high level one!!!!

 

Thanks to Drazen for the test!

 

Giorgio

 

I suggest you use less colored, better balanced 6SN7GT.  Sylvania, Raytheon, Ken-Rad 6SN7GT will sound better.  The most linear tube is the Sylvania 6SN7W, but very expensive, if you can find them.  You could also use any of the prefect electrical substitutes for the 6SN7GT provided you buy pin adapters. 





Click to expand...

 
Jul 11, 2014 at 3:03 PM Post #56 of 58
edmond dantes said:
  Sorry, I've used this tube: "1950's Sylvania 6SN7GTW", as you can read in my post... Do you prefer a Sylvania 6SN7GT? Differences? Or is your suggest related to 6N7 tubes?
 
Thx
 
Giorgio  
Click to expand...

Sorry, I didn't catch that.  My mistake.
 
But, I'll go on, anyway. The US versions of the 6SN7GT/VT-231 were made by GE, RCA, Sylvania, Raytheon, Ken-Rad, Tungsol and National Union. All of them made at least several versions. (I've forgotten at least one US mfr)!  The 6SN7W was made exclusively by Sylvania.  The 6SN7GTW was only made by Slyvania and Raytheon, I think.  They all sound different, some radically different, some just a little different.  My favorites are the Raytheon 6SN7GT/VT-231 T plate and th Sylvania 6SN7W tall bottle with the metal base.  
 
I have a couple of 6SN7GTW made by Slvania.  They came with an Audio Note amp. They are OK, but they are a bit too colored and lack some detail.  
 
The 6SN7GT, A and B models were once everyone's favorite driver tube and phase splitter.  But those days are over.  More "modern" designs are going to Pentodes and generally getting away from SRP front ends, but I still love them.  
 
Jul 13, 2014 at 5:37 AM Post #57 of 58

HAD AudioLAB Maestral III - extended impressions

Edited for colourful language and formatting from the post on reddit: http://www.reddit.com/r/headphones/comments/2akoo0/had_audiolab_maestral_iii_amplifer_extended/
 



 
 

TLDR: It sounds good and it glows in the dark.

 

 

Preamble:

  1. My sound preference: Generally on the warm and dark side of neutral
  2. Source used: PC --> USB --> Yulong D100 MkII --> Cheap audio switch --> Amps
  3. Headphones used: HiFiMan HE-500, Audeze LCD-2, Sennheiser HD 800
  4. Time spent with product: A bit over 2 months

.

.

What is it?

  1. Manufacturer product link: http://www.had-audiolab.com/products/power/maestral-three-headphone-amp[2]
  2. Description: It's a tube based headphone amplifier catering for both high and low impedance headphones. It has 2 gain settings (high/low), 2 configurations (SE OTL/CAT), single RCA input at the back, RCA bypass output, RCA preamp output, a single 1/4" locking jack at front, and most importantly a power switch on the front (noice!).
  3. OTL vs CAT: Basically it all boils down to what type of load you will be driving. OTL is better suited to high impedance loads, and the CAT mode (which as far as I can figure it is just a cathode autofollower) is more for low impedance headphones. In practice, I didn't notice too much of a difference between the two operating modes except that OTL was considerably louder than CAT mode (regardless of the headphone used).
  4. What do you get: Box, 2 x complete tube sets for the amp (nice), amplifier, power cord.
  5. Price: 649 EURO / 889 USD + shipping

.

.

How does it sound?

  1. Bass: Decent extension and punch but it does fall behind in both when compared to the Soloist and the Project Ember.
  2. Mids: Good, not as thick sounding as the Ember when using a Telefunken 12AU7 (the only tube I used for the whole comparison), slightly more prominent sounding compared to the Soloist, though I suspect it's down to the Soloist being noticeably brighter which draws my attention away from the mid range.
  3. Treble: Not as bright as the Soloist (very noticeable with the HD 800) but not what I would consider recessed treble. Lacks a bit of air compared to the Soloist as well (noticeable when using the LCD-2). Definitely brighter than the Ember.
  4. Noise: With the LCD-2 and HE-500, no noise was noticeable at high gain with the volume maxed out in either OTL or CAT operation. With the HD 800, a hiss was present when using high gain on OTL mode with the volume knob turned past 2 o'clock (you'd go deaf if you listened to it at this volume).
  5. Soundstage and Imaging: Maybe (and that's the keyword here) slightly less expansive sounding than the Soloist but not by much. A bit wider sounding than the Ember. Imaging on the Maestral seems similar to that of the Soloist and better than the Ember.
  6. Headphone Pairing: Favourite pairing was with the HD 800 running in OTL operation/low gain, it just sounded good. Certainly better than the other two amps used in the comparison (HD 800 and Soloist pairing is imo very poor, far too bright). HE-500 was decent with the Maestral if a bit lacking in the bass department. The LCD-2 I flat out prefer with the Soloist as it tends to the bring the treble a bit more forward and the bass just sounds good and tight.

 

 

 

 

Build Quality:

  1. Materials: Walnut panels (top and sides), milled metal (not sure what type) panels painted black (top, front, underside, and back), Corian[3] (decoration on the front panel). The wooden panels are finished with a coat of oil and the user is meant to apply a fresh coat every month or so (which I have so far neglected to do because I’m a lazy person).
  2. Construction: The exterior fit and finish is very good, no large gaps between panels, no surface marks on delivery.
  3. Connectors and jacks: Front ¼” jack is a locking (I’m assuming Neutrik) type, which personally I’m not a big fan of (it’s just an added hassle to switch between headphones). Rear RCA connectors are decent I guess, nothing really stands out about them. Tube sockets are not really recessed so the base of the tubes sits more or less flush with the top panel (makes replacing them very easy). Some of the sockets do feel a bit loose (the sockets for the regulator tubes in particular feel like there is a bit too much wiggle room).
  4. Internals: This was probably the most disappointing aspect of the entire amp. Seriously, the internals look like a mess (see pictures below)... I should note that when I received the amp I noticed something was rattling inside. A bit of vigorous shaking and it turns out that a loose bit of solder was floating around inside the case.
  5. Knob Feel: It feels good brah. Seriously though the turning action is smooth, the knob is knurled, and it sticks out far enough so you can get a good grip.

 

 

 

 

Purely subjective rankings:

  1. Bass impact: Soloist >= Ember > Maestral III
  2. Bass enjoyment: Soloist > Ember > Maestral III
  3. Mids lushness: Ember > Maestral III > Soloist
  4. Mids enjoyment: Maestral III > Soloist > Ember
  5. Treble air: Soloist > Maestral III >> Ember
  6. Treble enjoyment: Maestral III > Soloist > Ember (still prefer the LCD-2 with the Soloist)
  7. Soundstage width: Soloist >= Maestral III > Ember
  8. Imaging: Maestral III = Soloist > Ember
  9. Perceived noise floor (lowest to highest): Soloist > Maestral III > Ember

 

 

 

 

Other notes:

  1. Heat: The amp does get hot. The metal plates at the top get too hot to touch and obviously you won't want to touch the tubes either.
  2. Power and gain: The Maestral III has significantly less headroom compared to both the Ember and Soloist when driving any of the tested headphones. With the LCD-2 and the HE-500, 12 o'clock on the volume knob in high gain, CAT mode, seems to be loud enough for me. The volume knob is set to about 1 o'clock when using the HD 800 with the same configuration. In OTL mode, all 3 headphones sound pretty good with the volume knob left at 12 o'clock on low gain.
  3. Warming up: I usually give the amp a couple of minutes to warm up before doing any listening.
  4. Tube rolling: Haven't tried anything apart from the stock tubes so no comment at this point in time. The options do seem fairly limited though.
  5. A word on soundstage and imaging: I find it quite hard to accurately judge soundstage differences so be aware that like everything else above, I could be full of schtako.
  6. Volume matching: I don't have anything to really help me accurately volume match the output levels of each amp. I tried to get as close as possible by just running a 1kHz test tone and listening by ear (yeah, not very precise...).

 

 

 

 

Pics:

 
  1. Internals: http://imgur.com/a/eqyA1
  2. Exterior: http://imgur.com/a/YjxXm
  3. Random: http://imgur.com/a/T1YiX
 
Aug 10, 2014 at 7:54 AM Post #58 of 58
Dear thanks for the detailed impression!! I didn't listen to the Maestral III, but instead I had the possibility to try the Maestra II that sounded so good that I decided to go with the Zephyr custom 2a3/45 that indeed is the best dynamic amplifier I've ever had at home (and actually I had tons of them..)!!
 
By the way!! I've just noticed on the site that the Maestral II is on discount till the end of september at 499 EUR!! This in very good for a tube amp inside Europe! I don't feel shy to suggest it wholeheartedly!!!
 
http://www.had-audiolab.com/amplifiers-croatia/
 
Marco
 
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