[DecentLevi]

(copying my message from the 2359 Glenn thread since this applies to the Euforia)
​

Now then folks, I finally got around to comparing the sonic difference of my upgraded power cord vs. stock, and my top Furman power conditioner vs. direct to mains power.

Already I was using the Furman IT Reference 15i Discrete Symmetrical Power Filter, 15 Amp:

Using stock cables, I was able to hear a highly substantial difference in sound - overall more lifelike and resolving and smooth. Thinking I may not be getting the full benefit of this top power conditioner, I recently went for the WireWorld Aurora 7 power cord. It's their 5th of 8 cords ranging from $60 - $1,700 for 1 meter. I got this one new in 1.5 meters for $170.

Instantly when plugging in the Aurora 7 cable I knew something special was happening! I was transported into a world of marvelous fidelity where every aspect just knew no boundaries and just does not stop - full stop! The sound I was getting now (on HD-600 with silver cable and custom Euforia tube amp fed by Schiit Modi 2 Multibit coaxed along nicely with a series of two very nice USB components / reclockers) was HIGHLY organic / lifelike with that x-factor of realism and visceral impact, very much deeper into the scene, FR seemingly wider with treble equally as full but more smooth, bass went deeper and more thunderous, vs. more 'digital' and narrow soundstage with a freebie black power cord.

After enjoying this new cord for 7 days I just went back to 'dinosaur land', comparing it to a standard user's freebie black power cord directly into a generic power strip. I noted the sound now as a very congested soundstage and a 'gluey' instrument separation; everything sounded cohesive and good, but layering was somewhat glued together in a sort of 'blob'; very harsh treble on semi-bright recordings that did not sound that way with the upgraded power cord and conditioner - an overall artificial sound. Drums do still hit as hard, but are totally lacking the organic and and 'natural' feel. Bass was not as deep, and everything sounded by contrast as if it was lacking harmonics that I previously heard with the above two upgrades.

Next I tried the upgraded Aurora 7 power cord alone directly with a generic power strip. Compared to a generic black power cord I actually heard an improvement! Now I'm hearing a more resolving overall sound - smoother, wider frequency response with treble exactly as present but smoother and deeper bass too... but finally after going back to the Furman power conditioner with Aurora 7 cable I notice "TREMENDOUS, FAR REACHING improvements in every aspect" (sic) as underlined above; as if I were listening to a completely new rig!!!

Mind you, this much improvement was without even upgrading the power cord to the external transformer so the difference could have been even greater if I had upgraded all cables!

Above are three power cables:
1. generic black power cord
2. generic black power cord (extra thick copper)
3. Wireworld Aurora 7 silver-clad OFC 12 AWG copper cable with a flat design.

I was already using the 'thicker' black cable, but the tremendous improvements came when upgrading to this blue cable, and were noticeable both with / without a power conditioner, but heightened immensely with both together.

 

[OctavianH]

I think the most important are the cables at the output of the conditioner.
Anyway, I had good results with Supra cables, and at the moment I use some of these Supra LoRad 2.5 SPC CS-EU:

 

[connieflyer]

Still waiting on the adapters for the 7581a tubes, so took the opportunity to try some combo's I have not tried in the past. This time it was a pair of Dairio EL38's for power and a pair of CV 1052's for drivers. Strong vocals and treble. Bass is still quite nice with solid presentation

 

[barontan2418]

First two 7581A adapters arrived so added them as drivers to my 7581A's power tubes already in situ. No where near enough hours on them yet to give any valid opinions, however running the 7581 as power tube and EL32's as drivers has been a success, up there with the EL11 EL38 combo in my opinion anyway.

 

[teknorob23]

First two 7581A adapters arrived so added them as drivers to my 7581A's power tubes already in situ. No where near enough hours on them yet to give any valid opinions, however running the 7581 as power tube and EL32's as drivers has been a success, up there with the EL11 EL38 combo in my opinion anyway.

Mine ordered from @Deyan on Friday less than a week after i'd ordered them. They look great, working as advertised which and the first pair of 7581a's have about 30 hours running as powers. So far they sound okay, very clean and open, but the bass is a way off the 39s. @hypnos1 i've lost track a little with burn in times, sorry i'm sure you've already mentioned it, but how long was it before you found they came properly on song? thx

 

[connieflyer]

Well, no adapters in the mail today, so trying a different driver. Dario EL 38 powers and Marconi VT 52 for drivers. Close to the CV 1052's a little more open, laid back.

 

[Scutey]

Well my adapters arrived today as well!. Managed so far to get 15 hours on mine, now I can burn them in properly without the wire failing. Like @teknorob23 i'm finding them very clear, detailed, open, bass is good, tight, punchy and detailed, not sure if they're as good as the EL38/39 yet, not as warm/dark either, but they are certainly promising, one thing they do need, imo, is a warmish driver tube else they could sound a tad clinical.

 

[hypnos1]

First two 7581A adapters arrived so added them as drivers to my 7581A's power tubes already in situ. No where near enough hours on them yet to give any valid opinions, however running the 7581 as power tube and EL32's as drivers has been a success, up there with the EL11 EL38 combo in my opinion anyway.

Mine ordered from @Deyan on Friday less than a week after i'd ordered them. They look great, working as advertised which and the first pair of 7581a's have about 30 hours running as powers. So far they sound okay, very clean and open, but the bass is a way off the 39s. @hypnos1 i've lost track a little with burn in times, sorry i'm sure you've already mentioned it, but how long was it before you found they came properly on song? thx

Well my adapters arrived today as well!. Managed so far to get 15 hours on mine, now I can burn them in properly without the wire failing. Like @teknorob23 i'm finding them very clear, detailed, open, bass is good, tight, punchy and detailed, not sure if they're as good as the EL38/39 yet, not as warm/dark either, but they are certainly promising, one thing they do need, imo, is a warmish driver tube else they could sound a tad clinical.

Hi guys...will answer your posts en masse, if that's OK

Glad you're finding them good on the whole already. But yes - especially you tr, you'll need many more hours yet for these babies to shine...especially for bass to develop fully.
As powers - in my own experience at least - it was well over 50 hrs before they came anywhere near the El38/39s. And it took even longer before I was happy with stage width/3 dimensional space and extended tonal range...(but a word on bass later ).

As drivers, my initial disappointment has turned into a fair degree of wonder. And so in this role I will stress once more...you MUST wait even longer than as powers before sounding half decent (in my own case once again, that is). I personally wasn't very impressed at all right up to 40 - 50 hrs at least lol!

As foursome, what has struck me most has been the mids presentation...and this is where the 7581As as drivers also provide more of that warmth you mentioned Scutey...much more so than with the 'standard' EL11. In fact, I have never heard such a wealth of midrange coverage before from any tube combination of mine....even the mighty ECC31 (basically an ECC32, but with common cathode).

And so, with a pair of powers well over the 100 hrs mark, and two drivers not too far behind now, all aspects of delivery are up there with the EL11/EL38 and almost the EL39...but as I mentioned, actually with even better mids lol! However, at this point I must confess to a revelation : after finding what my slightly different Mazda EL38 brought to the table when partnering an EL39, I swapped one of the 7581A powers for said 39 (in the left channel) and...WOW! Just a tad more solid bass, but even more importantly a certain je ne sais quoi that lifted the performance even further overall. Actually, it brought a little more treble sparkle to joust with the Tung Sols' mids, giving a very seductive and scintillating sound....and all without taking away the latters' wonderful treatment of female (and male!) vocals, not to mention all woodwind and brass instruments. It also helped open up the stage a little more and give the impression of being even wider. In short guys, and for me at least, this 7581A trio and single EL39 has taken me quite by surprise, and until I can do proper quick A/B with my previous reference combo, I would place it right up there around the top...possibly even equal first, but with slightly different presentation.

All of which makes me even more eager to hear others' findings...either as twosome or foursome (Edit : or threesome) lol!

ps. My adapter (for testing purposes) arrived today from xulingmrs, and performs admirably. Will find it interesting also to compare soundwise with my own DIY efforts. Nice that we have two adapter sources to choose from! ...GOOD LUCK guys, and HAPPY LISTENING!...CJ

 

[LoryWiv]

It's interesting to read the evolving impressions of the Tung Sol 7581a. Sounds very promising as power, perhaps driver as well although for us Elise users it's heater current of 0.9A might preclude using as drivers with standard output tubes of 2.5A --> total for the 4 tubes of 6.8A,exceeding the 6.5A ceiling that I believe Elise has.

On another note, it appears one of the unique characteristics of the 7581a is a high plate dissipation of 35, and some say this correlates to "headroom." I don;'t want to overthink this, as if it sounds great that's what matters, but how does "headroom" affect sound quality? Is it capacity for transiently higher currents? Does the amp circuitry have to be able to match it for this to matter?

BTW, I'm one of those guys for whom:
A) A little knowledge is dangerous.
B) Understanding the "why" helps me wrap my head around things and decide on the "what" I want to pursue.
C) (A) & (B) are probably a bad combo. as trial and error for what sounds good in our systems should probably weigh more than 1st principle reasoning.

 

[DecentLevi]

@hypnos1 I do believe it was you who initially convinced me to go the power conditioning / power cord route, so I would like to say a big thanks is owed to you for the newly heightened level of sonic enjoyment I'm receiving from my Euforia (mentioned on top of this page). I am now not only a believer but an opponent (LOL ) proponent of power conditioning being an integral component to yield superior sonic performance with almost any hi-fi rig (with the exception of systems powered with an AC/DC wall wart, which I've tested to have no effect).

 

[DecentLevi]

It's interesting to read the evolving impressions of the Tung Sol 7581a. Sounds very promising as power, perhaps driver as well although for us Elise users it's heater current of 0.9A might preclude using as drivers with standard output tubes of 2.5A --> total for the 4 tubes of 6.8A,exceeding the 6.5A ceiling that I believe Elise has.

(...)

Though I'm not officially endorsing it, I do recall quite a few combos operating stable at right around 6.8ah on both Elise and Euforia. I'm sure H1 may have better input on this. And at least there should be no worry at all on current draw if using the 7581A's as powers with other EL series tubes.

Hey would sometime mind to give me a definite answer whether or not KT66 tubes would be compatible in a 7581A or 6V6 to 6AS7 adapters that are currently available from @Deyan or Mrs. XuLing? I may want to give my NOS GEC KT66's a spin in the Euforia... in the name of science HaHa.

Another question: Does anyone happen to know the cathode bias resistance ohm value (Ω) of the EL39, EL12 Spez and 7581A tubes? The reason I ask is first out of curiosity if these three tubes are close to being properly biased on our F.A. amps, as well as a potential plan to configure them more properly for an upcoming custom amp. Scouring the web for data on those three tubes yields no such data, where it should be shown under the "Rk" ohms / Ω value but it's not there on any of the schematics I've found.

 

[LoryWiv]

Another question: Does anyone happen to know the cathode bias resistance ohm value (Ω) of the EL39, EL12 Spez and 7581A tubes? The reason I ask is first out of curiosity if these three tubes are close to being properly biased on our F.A. amps, as well as a potential plan to configure them more properly for an upcoming custom amp. Scouring the web for data on those three tubes yields no such data, where it should be shown under the "Rk" ohms / Ω value but it's not there on any of the schematics I've found.

I thought Elise / Euforia were auto-biasing...are there parameter limits to this?

 

[hypnos1]

It's interesting to read the evolving impressions of the Tung Sol 7581a. Sounds very promising as power, perhaps driver as well although for us Elise users it's heater current of 0.9A might preclude using as drivers with standard output tubes of 2.5A --> total for the 4 tubes of 6.8A,exceeding the 6.5A ceiling that I believe Elise has.

On another note, it appears one of the unique characteristics of the 7581a is a high plate dissipation of 35, and some say this correlates to "headroom." I don;'t want to overthink this, as if it sounds great that's what matters, but how does "headroom" affect sound quality? Is it capacity for transiently higher currents? Does the amp circuitry have to be able to match it for this to matter?

BTW, I'm one of those guys for whom:
A) A little knowledge is dangerous.
B) Understanding the "why" helps me wrap my head around things and decide on the "what" I want to pursue.
C) (A) & (B) are probably a bad combo. as trial and error for what sounds good in our systems should probably weigh more than 1st principle reasoning.

Hi LW...'A' can certainly be very dangerous in certain circumstances, which is when caution must always prevail...in all walks of life lol! And although our ears and brain are the best judge of what sounds 'good' or 'right' for us as individuals, whatever knowledge we can back this up with not only strengthens our enjoyment through greater understanding of just what's happening during the experience, but can of course help us possibly stay on the safe side!

And don't forget that the first bit of knowledge can then become a springboard for further research, if interested/needed...so, mon ami, stay curious lol!
ps. head-fi's 'Glossary of terms' can be a good starting point at least for certain info : https://www.head-fi.org/articles/glossary-of-terms.13562/

As to your queries, 'headroom' does indeed refer to the effects/benefits (but sometimes overstated!) of higher power operating conditions. Re. the 7581A, its more highly rated internals/plate allow for it to be pushed harder for greater output (thus greater 'headroom') than the standard 7581 or 6L6. However, in amps such as ours that are not driving them so hard, it's probably debatable as to the extra benefits lol! And so, therefore, if the price of the Russian reissue Tung Sols were much higher than the standard 7581/6L6/GC, I doubt the extra cost would be good value for money. Mind you, I do always like tube versions that have been built more ruggedly...as per military use ones, even though that's not necessarily a guarantee of better sound quality! And despite the occasional Russian bottle having a slight 'tilt', it's otherwise extremely well built...

Re. heater power requirements, I personally would NOT want to be running our amps at 6.8A and do not recommend it! This is why I stopped using the excellent ECC31 as driver, much as I loved it...the total of 7A (when used with 5A of power tubes) had the amp running far too hot for my liking! ). But apparently the Anniversary/Special Edition Euforia does indeed have an uprated transformer that should be able to handle such a figure much more safely...

I thought Elise / Euforia were auto-biasing...are there parameter limits to this?

Our auto-biasing will indeed have the tube running at what the amps require, but this may not necessarily be the best operating point that the tubes themselves are designed for! And which is what surprises/baffles me most about Euforia and Elise being able not only to actually run so many 'alternative' tubes, but also to be handling them at what must be very close to their optimum, given their superlative performance (on the whole!). And if there was a bad mismatch, it would soon be obvious to the listener lol! So, for us especially...thank heavens for auto-biasing...even though normally, a separate bias setting function is more likely to be closer to the ideal ...(if used correctly!! )...

 

[hypnos1]

@hypnos1 I do believe it was you who initially convinced me to go the power conditioning / power cord route, so I would like to say a big thanks is owed to you for the newly heightened level of sonic enjoyment I'm receiving from my Euforia (mentioned on top of this page). I am now not only a believer but an opponent (LOL ) proponent of power conditioning being an integral component to yield superior sonic performance with almost any hi-fi rig (with the exception of systems powered with an AC/DC wall wart, which I've tested to have no effect).

My pleasure, DL...and glad to see another convert to upgraded mains power conditioning/filtering and cords/cables. I found this a long while ago with all cables, and my graduation from an early Tacima conditioner (not the much inferior later strip kind!) came courtesy of Acapella11 and a member at a local meet a few years back (the AirlinkTransformers Balanced Mains units). Looks like you now have a very nice combo yourself lol! ...ENJOY!...

ps. I myself don't see why there should be any problem using the KT66 in the adapters you mentioned (same pinout), and in theory, the old versions could in fact sound even better lol! But given our amps aren't natively configured for these tubes, who knows lol?!!...another case methinks of suck it and see!!...GOOD LUCK!...CJ

pps. Sorry, don't know the precise bias settings for our amps alas...

 

[hypnos1]

OK guys, just a quick note on 7581A use - and other 'alternative' tubes in fact lol - ie. re. adapters, and particularly re. bass response @teknorob23 !!

This is the first time I've actually compared 3rd party adapters with my own, and as I suspected, my use of high quality components does indeed make quite a difference to the final sound...in my own particular system at least. But then, for my 7581A adapter I used teflon sockets, with multi-segment gold plated pin receptors (and beautiful they are too ), along with Neotech mono crystal UP-OCC solid silver and copper wires, with added silver/gold-infused (not coated) wire!! So it's hardly surprising really, I suppose (thankfully!). But, of course, for such an animal to be made thus commercially, with sufficient profit margin would mean a very unattractive price alas .

Anyway, in short, I was actually rather surprised at the difference - and this with just one adapter other than my own. So with more - especially four! - I'm afraid those with highly resolving systems won't be getting the best possible results from tubes that require 3rd party adapters...full stop! And which, given the sonic differences that even mere connectors elsewhere in the system can make, this - to me - is self-evident lol...viz. all aspects of bass response; treble clarity/extension; soundstage width/3-dimensionality/separation, to name just a few!

However, despite this finding, I have to say that the sound from the 7581A with 3rd party adapter was still extremely good lol...and certainly a match for any other conventional tube IMHO ...CHEERS!...CJ