[ZRW0]

It seems to me the Chrisdrop is describing hum from the amp itself and not from a tube. You could try to ground the amp to a metal water pipe or such, but I never had luck with it.
Sometimes a different electrical outlet helps - RFI could come from various appliances, lights and electric motors.

Yes, I fully agree with you Mordy.

I already told Chris the hum that he was hearing was very likely coming from the power supply of the Euforia, that he was "hearing the 50hz AC", and very unlikely coming from the tubes. The hum at Volume 0 is a good indicator of that.

What really puzzles me (and even embarasses me), is that my home is not very EMI friendly either (Strong Wi-Fi, DECT landline, cell phones...), and the Euforia neither hummed with the stock tubes nor with the EL tubes I sold to @chrisdrop .

Yesterday, I was thinking about a ground loop between his DAC and the amp (seems Chris' DAC isn't grounded, but I've been using a Hugo2 for a while which isn't grounded either - but from USB connection, maybe - and never hit this issue), but Crhis seems to have some humming whatever is connected to Euforia's inputs...
Could the Euforia's journey between the French Alps and London have impacted the power supply or any other internal component ? (airplane pressure acting on condensators ? But I'm not even sure the amp took the airplane actually)

 

[mordy]

Whatever the problem with the hum is, if you persist you will be able to fix it.
Did you try plugging it in in a different house?

 

[chrisdrop]

Tx all for the supporting guidance. I am going to take it to my office tomorrow to see on a totally different power setup and see what happens there.

Notwithstanding the hum, so far I love the thing!

 

[hypnos1]

Yes, I fully agree with you Mordy.

I already told Chris the hum that he was hearing was very likely coming from the power supply of the Euforia, that he was "hearing the 50hz AC", and very unlikely coming from the tubes. The hum at Volume 0 is a good indicator of that.

What really puzzles me (and even embarasses me), is that my home is not very EMI friendly either (Strong Wi-Fi, DECT landline, cell phones...), and the Euforia neither hummed with the stock tubes nor with the EL tubes I sold to @chrisdrop .

Yesterday, I was thinking about a ground loop between his DAC and the amp (seems Chris' DAC isn't grounded, but I've been using a Hugo2 for a while which isn't grounded either - but from USB connection, maybe - and never hit this issue), but Crhis seems to have some humming whatever is connected to Euforia's inputs...
Could the Euforia's journey between the French Alps and London have impacted the power supply or any other internal component ? (airplane pressure acting on condensators ? But I'm not even sure the amp took the airplane actually)

Hi Erwan...there's always the possibility of damage in transit of course, but this seems to be a rare occurrence, thank goodness!
A serious contender as culprit is still IMHO the mains electricity supply, if nothing in the house is playing gremlin lol . Especially as sometimes here in the UK our mains voltage can vary quite a bit from 'pure' 240V, and if over this figure can possibly create problems in sensitive equipment that's manufactured to 230V spec...which is your mains voltage in France, non?

Tx all for the supporting guidance. I am going to take it to my office tomorrow to see on a totally different power setup and see what happens there.

Notwithstanding the hum, so far I love the thing!

Hi chris...another location should indeed help to eliminate things further...hopefully!! ...GOOD LUCK tomorrow!...CJ

 

[hypnos1]

UH Oh, a bit of bad news on the 4x EL39's I said are coming up. The seller posted the ad but upon checking they are the red band version - NOT RECOMMENDED per @hypnos1 unless I could be wrong?
https://www.ebay.com/itm/383167291499?ViewItem=&item=383167291499&ssPageName=ADME:L:LCA:US:1123

Yo DL...according to the French enthusiasts' blog, the version with red band is not in the same league as the later silver banded one - the so-called 'ProGold', with the gold signal grid wires. So I trust their judgment lol!

 

[ZRW0]

Hi Erwan...there's always the possibility of damage in transit of course, but this seems to be a rare occurrence, thank goodness!
A serious contender as culprit is still IMHO the mains electricity supply, if nothing in the house is playing gremlin lol . Especially as sometimes here in the UK our mains voltage can vary quite a bit from 'pure' 240V, and if over this figure can possibly create problems in sensitive equipment that's manufactured to 230V spec...which is your mains voltage in France, non?

Si ! (same as you guys in UK)
On the paper, EDF (the historical and principal electricity provider in France) writes down in its contracts that the 230v they provide can vary in a significant way: from +6% to -10%.
I'd say that such variations are rare to my knowledge, and can be seen when living rather in the countryside than in a town.
In cities, it's relatively stable and close (but a bit below) 230v (until the late 80s the standard voltage in France was 220v).

 

[chrisdrop]

OK. Latest update on my Euforia hum. Short story .

New experiments attempted: all with just amp + headphones + tubes. No other DAC, etc needs to be plugged in to hear the hum. (The buzz is certainly there w/ DAC, etc, but wanted to factor out to minimal components.)

• Moved whole setup to my office. Entirely different power setup. Room with nothing, closed door, no phones, etc. Institutional London City building. Same hum.
• Try expensive Chord power cable. Same hum.
• iFi AC iPurifier. Same hum.

Moving to my office seems a convincing evidence that there is a core issue. Given that the issue exists in different buildings with different power setups, different ambient electronics, I think it is an amp issue. It could be that it is insanely sensitive to any power setup? There are probably 1/6 dozen (all solid state) headphone setups (amp, DAC, or mobile like Mojo) at my office and there are no problems like this. The hum is worse with the set of tubes (ELs). It is certainly there with the stock tubes. If it was just in the stock tubes, my wife would say I was being picky. I think anyone here would say it was not right. The ELs are really buzzy however - not black at all.

So - any other ideas, aside from giving it a shipment to Feliks? The only other thing would be to try a power conditioner, which may be good in the long run, but if it has the issue in my home and my office, it seems like it would happen anywhere?

Thanks again for hearing my sob story and offering ideas.

Best
Chris

 

[hypnos1]

OK. Latest update on my Euforia hum. Short story .

New experiments attempted: all with just amp + headphones + tubes. No other DAC, etc needs to be plugged in to hear the hum. (The buzz is certainly there w/ DAC, etc, but wanted to factor out to minimal components.)

• Moved whole setup to my office. Entirely different power setup. Room with nothing, closed door, no phones, etc. Institutional London City building. Same hum.
• Try expensive Chord power cable. Same hum.
• iFi AC iPurifier. Same hum.

Moving to my office seems a convincing evidence that there is a core issue. Given that the issue exists in different buildings with different power setups, different ambient electronics, I think it is an amp issue. It could be that it is insanely sensitive to any power setup? There are probably 1/6 dozen (all solid state) headphone setups (amp, DAC, or mobile like Mojo) at my office and there are no problems like this. The hum is worse with the set of tubes (ELs). It is certainly there with the stock tubes. If it was just in the stock tubes, my wife would say I was being picky. I think anyone here would say it was not right. The ELs are really buzzy however - not black at all.

So - any other ideas, aside from giving it a shipment to Feliks? The only other thing would be to try a power conditioner, which may be good in the long run, but if it has the issue in my home and my office, it seems like it would happen anywhere?

Thanks again for hearing my sob story and offering ideas.

Best
Chris

Hi Chris.

This is just too cruel! It looks like you've done everything humanly possible to trace the cause, and so as your amp must still be under warranty, it would appear your next recourse must be to let Lukasz know at : info@feliksaudio.pl , giving him all the details of what you've tried so far (of course!). Given that all was fine with Erwan, presumably you have been very unlucky indeed with something happening during transit.

It does appear that F-A have been having their usual long Summer break...along with their interim auto messaging of such to any enquiries!! (if they ever managed to fix it after previous malfunction lol!). I myself am still awaiting reply...

I'm so sorry you're having a less-than-ideal start to your time with Euforia, but hang in there and I'm sure this (frustrating!) hiccough will have a fairly simple remedy.

Sympathy and best wishes go to you Chris....CJ

 

[ZRW0]

Well, I confess I'm quite embarrassed by the situation too.
And if I had detected anything, I'd had for sure sent my Euforia back to Poland for a good revision before selling it...
Let's see how things go with Lukasz, and what has become faulty in this amp.
This might be instructive for others here as well.

 

[chrisdrop]

To be 100% clear; @ZRW0 - you have been great. I am certain that you had no issues with this amp and would have done as you say. Your help is greatly appreciated.

 

[hypnos1]

Well, I confess I'm quite embarrassed by the situation too.
And if I had detected anything, I'd had for sure sent my Euforia back to Poland for a good revision before selling it...
Let's see how things go with Lukasz, and what has become faulty in this amp.
This might be instructive for others here as well.

Hey Erwan...these things happen on the odd occasion, so not your fault lol . I must admit that tube amps have proved much more 'challenging' than solid state...have lost count of the number of times I've had to take a deep breath with mine over the years! And have certainly come to appreciate the need for super patience!! But usually all comes right in the end, as I'm sure it will for Chris .

 

[DecentLevi]

EL39 sale alert. 5 days remaining on Yahoo JP auction, with two extra rare bonus tubes that may / not be compatible
http://yahoo.aleado.com/lot?auctionID=j593943496#enlargeimg

 

[hypnos1]

EL39 sale alert. 5 days remaining on Yahoo JP auction, with two extra rare bonus tubes that may / not be compatible
http://yahoo.aleado.com/lot?auctionID=j593943496#enlargeimg

Hmmmm...haven't had any experience of this particular Japanese auction site, and from what I can glean from the various info links there seems to be quite a lot one needs to take carefully into account lol! Note also the $65 to $68 shipping charge!! Plus a Yahoo auction fee and 'Consumption' Tax? I'll stick to ebay, with its very good buyer protection these days thanks!

 

[hypnos1]

Ok, so here are a few words about my "new bringer of joy"

1. with some set of tubes, it can glow blue


Cheers,

Erwan.

Hi CJ,

The blue glowing tubes are TungSol (Russia) nowadays production 7581A.
Those are pentodes, drawing 0.9A current.
Given your valve adapter crafting skills, I don't see what could prevent you to give them a try on the Euforia

Regards,

Erwan.

Eh bien Erwan, looks like you'll either be in the 'dog house' or possibly the harbinger of a power tube to beat anything else at 2 to 3+ times the price lol!!

From all the rave reviews about this (ridiculously) cheap reissue (Russian) Tung Sol tube - not to mention that gorgeous blue glow lol! - I just can't resist the temptation to see if my Euforia can pull yet another rabbit out of the bag and welcome the 7581A aboard .

Assuming all is indeed well when plugged in - and that it performs superbly and safely - this could turn out to be a wonderful alternative tube for intrepid pioneers out there. At about $42 the pair (in USA), and an obviously plentiful supply, it would be a no-brainer!.

This is all conjecture at the moment of course, but certainly worth a try...especially as a simple link/strap in my EL39 adapter's socket should be all that's necessary lol .
One thing though, I doubt it will have quite the same degree of blue glow unfortunately - Euforia won't be pushing this tube anywhere near as hard as it would be in a power amp. Plus, it might well actually need that much higher plate voltage to perform near its best...so time will tell.......CHEERS!...CJ

ps. And so this could well engender more 'entente cordiale'...or start yet another Anglo-French War lol!! ...
pps. A photo of the incoming protagonists :

 

[DecentLevi]

Hmmmm...haven't had any experience of this particular Japanese auction site, and from what I can glean from the various info links there seems to be quite a lot one needs to take carefully into account lol! Note also the $65 to $68 shipping charge!! Plus a Yahoo auction fee and 'Consumption' Tax? I'll stick to ebay, with its very good buyer protection these days thanks!

I myself have dealt with Yahoo JP auctions a few years ago, with a former W.E. 421A tube and I was very satisfied with the genuine item and excellent shipping and tracking. Yahoo Auctions is one of the oldest, being around for over 20 years and Japan is highly regarded as a country of solid integrity, not to mention a mainstay and innovator of the hi-fi scene and an original manufacturer of headphones, tubes, SS and vintage tube amps. I just thought I'd post the link to give a chance to anyone who's yet to experience the otherworldly prowess of the EL39's and those look like they're in great condition, even a rare brand. Sure shipping is high but the bid currently stands at only at around $10. And I personally don't think I encountered consumption tax from them to the U.S.

No need to wait for me to recommend the next EL39 that may come up. Anyone still looking for a pair feel free to do a simple registration and save a search query on this site so you can get an email notification when the next tube you're after shows up, indexed from numerous sites.
https://www.hifishark.com/