[hypnos1]

. FINAL(?!) UPDATE ON 7581A AS POWERS AND DRIVERS

Right then folks, I must now admit to a very bitter-sweet confession : with well over 150 hrs on all my 7581A tubes, and 50+ hrs on 2x direct adaptations' wires plus one 'OTT' adapter, and with many of my favourite test tracks, the previous 'reference' combo - 2x mesh-plated EL11 drivers to 1x EL39/1x 'special' Mazda EL38 powers has more than met its match.

I never thought it possible, but for my own personal tastes - and in my own system - this combination of 2x Russian reissue Tung Sol 7581As (with 3 holes to the plate's sides) as drivers to 1x EL39/1x Tung Sol as powers is now delivering a sound I never imagined could come from my Euforia....viz...

1. Enhanced bass and treble detail/extension, in accordance with the quality of recording.
2. Upper bass and mids presence surprisingly greater than reference. In particular, male and female voices have more depth and richness (plus 'emotion'?), with an exquisite smoothness that counters even overly treble-oriented recordings. This extended tonal range also applies to wind instruments from flute, through trumpet/trombone to sax, horns and tuba.
3. Acoustic guitar - which I love! - also has an increased richness of tone that enhances a softer, lyrical voice particularly well.
4. Soundstage is even wider and more 3-dimensional, with pinpoint separation/positioning in space. This was highlighted big time especially in Fleetwood Mac's 'Oh Daddy' and 'Gold Dust Woman' from 'Rumours'...showcasing the truly masterful prowess of the recording engineer. I've never been so 'electrified' by these tracks!
5. Overall clarity across the FR is a notch higher...eg. the words " Morning...today's forecast calls for Blue Skies" as intro to ELO's 'Mr Blue Sky' have never been so clear. And this clarity brings a greater precision to entire recordings, without being in any way 'clinical'.
6. The overall delivery is therefore even more dynamic...even more exciting, and 'invites you' into the artists' performance - vocals particularly being neither too close (and in your face), nor too distant so as lose intimacy and involvement...for my own tastes, at least!

I now understand for sure that the way I convert my tubes helps a fair deal in maximising these very welcome attributes, but of course such differences should still apply between tubes from different families that require 3rd party adapters, but simply perhaps to not quite the same degree in total lol .

Whatever, today has been somewhat of a 'baptism in fire' for me, and I have mixed feelings about its consequences for my beloved mesh plate EL11s especially! But nonetheless, I'm happy that folks can - if they want to - probably achieve a superlative performance from their amps without having to spend a fortune. And I can only recommend that those with an EL38, or luckier still an EL39, try one as partner to a 7581A in the power slot, driven by 2x 7581As...if my own experience is anything to go by (?!)...CHEERS!...CJ

 

[connieflyer]

Excellent review H, looks like you've covered all the bases and what sounds like, and I really hate to say this because how many times have we heard ourselves say this before that these sound like as good as it's going to ever get with the euforia. But then someone comes along with tubes we have not thought of or considered previously and proves to my utter horror that I'm on the road again, well what are you going to do. You just jump in there try your best to see if we can get more enjoyment out of our amplifier and various and Sundry parts. Now I am quite sure, and fact I am positive that this is the last tube rolling that I'm going to do with this amplifier. After H's comment about the difference in the adapters that he has made compared to what the commercially available adapters are I know that my system is close to what he has, except of course for the all-important adapters. That being said I won't be able to get the absolute maximum out of any new tubes, so if my adapters ever get here, then this will be the last rolling for me at least with this amplifier. I am looking at one or two other amplifiers, for the future of course not right now. Well done H you have done it again!

 

[teknorob23]

Hi @teknorob23 ...sad to hear you've fallen foul of many a tube amp lover's gremlin...hum! Tubes are, of course, much more susceptible to sources of EMI and RFI that are around us everywhere these days (much more so than when tubes reigned before the arrival of transistors lol!), and which can manifest as hum, 'hiss', crackle of all sorts alas .
My Elise always had a very slight hum that didn't vary with volume setting, and never went away. My Euforia however was totally silent, once the prototype's initial heat issue was sorted.

With stock tubes in situ, and once all possible sources of interference have been eliminated (including cables/connectors/connections; different source and DAC tried if possible; mobile/portable 'phones/computers/laptops etc switched off), a different location/mains supply needs to be tried, also if possible.

By the way Rob. Hugo2's output at red/yellow is far too low IMHO...should really be blue/purple (line) level...give it a try before anything else to see if any change .

I do hope you manage to trace the cause soon, otherwise it could well be just the occasional unfortunate case of a component on its way out (can and does happen, of course...but hope not!!).

So here's wishing you GOOD LUCK!...CHEERS!...CJ

Thanks CJ, your reassuring words get down from the ceiling yet again. I have worked through all these checks and a few more, with the exception of moving everything to new location and trying repeating the exercise try to eliminate external interference. It came on while ive been burning in the tungsols so i was worried i'd over cooked something, but i did stick to 5-6 hour sessions with breaks but some of those had volume up to 3/4s.

Its my wife's birthday today and i'm not sure how an evening of re-locating the Euforia and tube rolling is quite what she's got in mind by way of celebration, but i will get it done at some point at the weekend. Worse case scenario, i guess it has to go on little journey to see it's parents in poland. Fingers crossed it doesnt come to that!

 

[hypnos1]

Thanks CJ, your reassuring words get down from the ceiling yet again. I have worked through all these checks and a few more, with the exception of moving everything to new location and trying repeating the exercise try to eliminate external interference. It came on while ive been burning in the tungsols so i was worried i'd over cooked something, but i did stick to 5-6 hour sessions with breaks but some of those had volume up to 3/4s.

Its my wife's birthday today and i'm not sure how an evening of re-locating the Euforia and tube rolling is quite what she's got in mind by way of celebration, but i will get it done at some point at the weekend. Worse case scenario, i guess it has to go on little journey to see it's parents in poland. Fingers crossed it doesnt come to that!

Hi Rob...the plot thickens, but not in the right direction alas!

So, you're staying with stock tubes for any further testing, of course...and didn't raising Hugo2's output level make any difference at all? And does the hum and eventual distortion increase as you raise the vol level...again, with stock tubes lol? External interference/mains noise usually remains the same regardless of the volume setting... and again, increasing noise level usually means either a tube(s) or the amp itself...but this isn't set in stone lol!!

And so, given the above are covered as well, and nothing changes/improves when you manage to test in another location, then it would certainly point towards the amp unfortunately...

Re. the Tung Sols, I can only say it must be a dreadful coincidence lol! ...you certainly didn't overdo the cooking from what you say, assuming your headphones weren't near to blowing!!! All four of mine had 9 to 10 hr sessions, often with just half an hour cooling down periods, and for well over 150hrs each at least. And all is still deathly silent...

I feel your pain when something like this happens, and I can only hope for some kind of miracle to get things back on track for you. And I certainly hope you don't spoil your good wife's birthday in any way for 'the other woman' in your life lol! ...the BEST OF LUCK, mon ami...CJ

ps. Rob, I just tried my setup with Hugo2 on just red/yellow output setting, and it's nowhere near high enough for what I personally regard as a 'good' volume setting on our amps...ie not too much over 12 o'clock max, especially for headphones. Don't know if there's any possible consequences of pushing our amps much above this kind of setting lol?!!

 

[teknorob23]

Hi Rob...the plot thickens, but not in the right direction alas!

So, you're staying with stock tubes for any further testing, of course...and didn't raising Hugo2's output level make any difference at all? And does the hum and eventual distortion increase as you raise the vol level...again, with stock tubes lol? External interference/mains noise usually remains the same regardless of the volume setting... and again, increasing noise level usually means either a tube(s) or the amp itself...but this isn't set in stone lol!!

And so, given the above are covered as well, and nothing changes/improves when you manage to test in another location, then it would certainly point towards the amp unfortunately...

Re. the Tung Sols, I can only say it must be a dreadful coincidence lol! ...you certainly didn't overdo the cooking from what you say, assuming your headphones weren't near to blowing!!! All four of mine had 9 to 10 hr sessions, often with just half an hour cooling down periods, and for well over 150hrs each at least. And all is still deathly silent...

I feel your pain when something like this happens, and I can only hope for some kind of miracle to get things back on track for you. And I certainly hope you don't spoil your good wife's birthday in any way for 'the other woman' in your life lol! ...the BEST OF LUCK, mon ami...CJ

It certainly does and as you say not in a way that fills me with optimism. It is persistent hum, similar to what you'd here when something's not earthed properly, then literally as the volume knob hits the buffer a maximum a random crackling or popping begins in the right hand side, while it just continues to hum on the left side. The sound changes constantly, but remains until i tweak the volume down slightly where it returns to humming on both sides. As you say i dont think the running was an issue and the volumes werent excessive, as i was killing two birds running in my Verite Closeds at the same time, which for record are outstanding. I'm doubtful a change in location will help but you never know and as sometimes things just get inexplicatbly better or worse. Fingers crossed its the former and anyway you right i do have to get back to the other women, thanks again rob

 

[hypnos1]

Hi again @teknorob23 ...did you see the ps. to my last post re. the Hugo2 output level and consequent very high vol setting for Euforia?...it crossed with your own post lol!!...CJ

 

[teknorob23]

Hi again @teknorob23 ...did you see the ps. to my last post re. the Hugo2 output level and consequent very high vol setting for Euforia?...it crossed with your own post lol!!...CJ

I didnt see, but have now. I use it as this level because i'm being lazy using the remote controlled H2 to control the volume. I've probably mentioned but i have sensitive left ear, from years of abuse and although i'm fortunate i still hear perfectly through it, i cant listen at high volumes sticking around 70-80db or i get residual tinnitus. Anyway i know where i am with H2 at red/yellow and i listen at five to on the euforia volume which has always be fine, although i totally agree its probably not ideal. But i guess i could have strained something

 

[hypnos1]

I didnt see, but have now. I use it as this level because i'm being lazy using the remote controlled H2 to control the volume. I've probably mentioned but i have sensitive left ear, from years of abuse and although i'm fortunate i still hear perfectly through it, i cant listen at high volumes sticking around 70-80db or i get residual tinnitus. Anyway i know where i am with H2 at red/yellow and i listen at five to on the euforia volume which has always be fine, although i totally agree its probably not ideal. But i guess i could have strained something

Hi again Rob...so you kept H2 on the very low setting but upped Euforia to 3/4s for burn-in. Don't know for sure, but that could possibly have not been too good for the amp's circuitry, but just guessing here lol! And have you tried another DAC? I know some folks have had issues with H2 alas......

 

[hypnos1]

Me again @teknorob23 ...re. the Hugo2, my own issue was with the crazily designed IMHO recessed RCA output sockets. My best connectors were too big to fit far enough into them to make reliable contact, and would have sent it back in disgust if it didn't sound so darned good lol! So, Rob, something to think about if even just for future reference!
Plus, another saving grace is the ability to use its remote control to in effect control the volume from Euforia via its (H2's) variable hp out level, as you say...

 

[teknorob23]

Me again @teknorob23 ...re. the Hugo2, my own issue was with the crazily designed IMHO recessed RCA output sockets. My best connectors were too big to fit far enough into them to make reliable contact, and would have sent it back in disgust if it didn't sound so darned good lol! So, Rob, something to think about if even just for future reference!
Plus, another saving grace is the ability to use its remote control to in effect control the volume from Euforia via its (H2's) variable hp out level, as you say...

I know they're ludicrously small rca, but i found this ETI Kryo plugs to miraculous in that they can accommodate 11.5mm neotech cable at one end and fit into the H2 diminutive holes at the other end.

 

[hypnos1]

I know they're ludicrously small rca, but i found this ETI Kryo plugs to miraculous in that they can accommodate 11.5mm neotech cable at one end and fit into the H2 diminutive holes at the other end.

Ah, tr...I went for the (supposedly better) KLE 'Pure Harmony' plugs, but had to file down the jaws to be able to get them anywhere near far enough into H2's sockets. However, even then the connection wasn't fully reliable. It wasn't until I bit the bullet and took H2 apart that I could see why...the positive cross-bar connection is set so far back, that unless the RCA plug's pin is longer than average, it will not establish (and maintain) a nice, secure connection. I could not believe that Chord would use such a potentially problematic component in something of this calibre/price. And so I decided to bypass said RCA sockets - and do away with any IC connector (best option of all lol!! ) - and took my Neotech cables' wires direct to the internal 6.3mm hp out connections...and it worked a dream!! And I actually found this output to be of a far higher quality, and far more impressive than the RCA outs...win, win! ...

 

[teknorob23]

Ah, tr...I went for the (supposedly better) KLE 'Pure Harmony' plugs, but had to file down the jaws to be able to get them anywhere near far enough into H2's sockets. However, even then the connection wasn't fully reliable. It wasn't until I bit the bullet and took H2 apart that I could see why...the positive cross-bar connection is set so far back, that unless the RCA plug's pin is longer than average, it will not establish (and maintain) a nice, secure connection. I could not believe that Chord would use such a potentially problematic component in something of this calibre/price. And so I decided to bypass said RCA sockets - and do away with any IC connector (best option of all lol!! ) - and took my Neotech cables' wires direct to the internal 6.3mm hp out connections...and it worked a dream!! And I actually found this output to be of a far higher quality, and far more impressive than the RCA outs...win, win! ...

way beyond my soldering pay grade, but one day! It would be lovely to never have to see another connector!

 

[hypnos1]

way beyond my soldering pay grade, but one day! It would be lovely to never have to see another connector!

Aha, way above mine also I'm afraid tr...H2's internal circuitry is insanely miniscule!!

No, I daren't risk trying to do any soldering inside this miniature marvel...much easier (if not quite so 'pure'!) to simply clamp the wires to the (well endowed) spring-loaded connectors of the hp female jack. If one didn't want to open her up, even easier of course would be to simply use a normal - but high quality - 6.3mm hp jack. But then, you're still back to that darned connector lol!! ...(but I'd rather that, than those awful RCA sockets! ). Speaking of which, if you haven't tried a different DAC, I strongly advise seeing if you have a pair of ICs lying about that have longer RCA pins than the ETIs, and give them a try...their pins look on the short side to me, just like my KLEs! I had similar symptoms to yours with my plugs not making good contact...???...GOOD LUCK!...CJ

 

[Johnnysound]

Euforia preamp (Valvo EL11/Philips EL39) driving a Jolida 3502C with 4 x RFT EL12N, TFK ECC801S and Mullard CV4004 “box plates” as “B” preamp

Trying to use a better pic, I deleted not only the fuzzy one, but my whole previous post...thankfully both @UntilThen and @hypnos1 quoted it, so I suppose it is “preserved” there. Some further 20 hours or so on the EL12N powers and the combo is now sounding...well, so ultra clear, transparent, dynamic, with a touch of warmth and such tight, defined bass that I am enjoying every minute of it.

This is all about synergy, of course: the very accurate, warm, slightly dark sound and powerful bass of Euforia (so configured) blends beautifully with the open and neutral, “sunny” sound of the German tubes...that showed exceptional control tightening over the bass frequencies.

Maybe I am repeating myself, but having another
“B” tube preamp against Euforia (with the same power amp) offered a quite revealing experience , specially if it is fitted with top notch, reference preamp tubes like Mullards CV4004 box plates and TFK ECC801S. And yes, it sounds excellent, these top Mullards are well known for their wide bandwidth and extreme bass, and the EL12Ns could handle them easily. Switching from “B” to “A” preamp (Euforia)...well, they were so close, both sounding so good, but Euforia was somehow quieter, relaxed, confident. The whole music presentation was free of any kind of stress, even at the most demanding passages. Bass was at a very high level, with some music better defined than with the Mullards, and I expected that from the mighty EL39s...but I also give credit to the Valvos EL11, quiet and extremely capable drivers. Anyway, both as preamp or power amp tubes, some members of the vintage “EL” family are showing their sonic virtues beyond any doubt...

 

[Scutey]

Came across this review of the 20th Anniversary Euforia today.

https://nikmind4u.tumblr.com/post/1...zfi2pM9gZWJAClFRtM3m4TZiKhl_-_crn-qGHzs5twf9A