[triggsviola]

So I bought some EL38s off of eBay just to see what all the fuss is about. They came from a guy in Cyprus! He said they were Mullard but they said CV450 KB/DA. I put them in and they work. The bass seems to be very energetic and the treble seems a bit attenuated compared to the stock 6AS7Gs. I'm intrigued by the difference in sound but not sure I like it yet. I'm using the stock CV181s as drivers. If I can find another pair for this cheap I might use them as drivers. Do the EL38s need to be a matched quad in this case?

I also find I have to turn the volume louder with these tubes than the stock ones. Anyone else notice?

 

[Johnnysound]

..

 

[ZRW0]

Oooohhh Erwan...tres joli!! I just luuuv blue!!

My only regret in years of tube hunting for our amps is that I haven't found one that glows such a lovely blue colour, and that we can use safely . Ah well, never mind...I firmly believe that the EL39 and 'special' Mazda/Dario EL38 have taken Euforia especially to a level that few can match anywhere near the price. And as you intimate, I'm sure few 'super' integrated tube amps either can surpass such a dedicated headphone amp lol . But I bet your PrimaLuna Evo 200 sure is one demon integrated!! ...HAPPY LISTENING!...CJ

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.

 

[ZRW0]

What is that? A primaluna?

Could be :-D

 

[hypnos1]

So I bought some EL38s off of eBay just to see what all the fuss is about. They came from a guy in Cyprus! He said they were Mullard but they said CV450 KB/DA. I put them in and they work. The bass seems to be very energetic and the treble seems a bit attenuated compared to the stock 6AS7Gs. I'm intrigued by the difference in sound but not sure I like it yet. I'm using the stock CV181s as drivers. If I can find another pair for this cheap I might use them as drivers. Do the EL38s need to be a matched quad in this case?

I also find I have to turn the volume louder with these tubes than the stock ones. Anyone else notice?

Hi triggs. The Mullard CV450 is indeed the military version EL38.

And it certainly sounds like they haven't had much use, if any lol. If NOS especially, it will be quite a while yet before the bass and treble particularly settle down, and the overall presentation become more balanced, along with much better separation/placement and wider/more 3 dimensional soundstage. They definitely won't shine until at least 50 hours' use, and then continue to improve well past the 150 hrs mark!

They do partner especially well with other EL family drivers, but the CV181s should also do a good job once the EL38s are burned in some more. Four EL38s can indeed be a very good combination, but as usual, the end result will depend upon the rest of one's system/ears/ personal preference!

Hopefully, with time - and becoming accustomed to differences in presentation, you will see more clearly just what these tubes can deliver . But again, your own experience is your own lol! ...CHEERS!...CJ

 

[hypnos1]

Of course, different experiences, but take into account that you are driving your HPs as transducers directly from a tube amp, moreover an OTL amp, utterly pure with no output transformer to smear the sound ! On the other hand, even with Euforia as preamp, your speakers are driven by an ss amp, so no matter how good your ss amp might be, the overall sound of speakers would be below HPs in terms of organic ”musicality” (to use this term). With a good tube power amp, things are much closer...the speakers sound like tubes, not like solid state, and the organic sound of Euforia is just right there, but amplified. In fact, Euforia drives ss amps much more easily than tube amps. It simply dominates ss amps sound in my experience, but had a much tougher time partnering with my Jolida Fusion, specially when the PA was fitted with 4xEL39s or 4xEL38s as power pentodes.

And I mean it, because this power amp has an optional preamp incorporated, one with 2x12AX7s plus 2X12AT7s that may look simple, but it is the 15th iteration of the same circuit, and believe me, simpler is better in audio. Of course, I rolled in the absolute best tubes of these types, and for the first time ever, Euforia was surpassed in terms of tight bass and detail...briefly. The arrival of the EL39s as powers, plus the Valvos (or RFT) as drivers returned Euforia to the top of the list. The refined,confident, airy and relaxed sound of the preamp was clearly superior. Frankly, it is a lot of fun to be able to compare Euforia “A/B” as a preamp against “holy grail” preamp tubes. Just rest assured that if these are “holy grail” tubes then Euforia must be the lost Ark !!

Ah, J...the old OTL vs SET amp debate lol! I must admit, it would seem if going for an output trafo, it needs to be a really top class (= very expensive) one. But I personally would still prefer being able to 'fine tune' the sound with different power(output) tubes...which, IMHO, can have a far greater impact than often regarded .

And it gladdens my heart to hear of your comparison between Euforia as preamp (with the EL tubes you mention) and 'holy grail' units .

ps. Your mention of the 'Lost Ark' certainly has me suspecting myself as the 'Raider'...when it comes to 'alternative' tubes at least lol!

 

[chrisdrop]

Hello all

As some of you will know @ZRW0 was kind enough to sell me his pristine Euforia. He and I have been doing a bit of hair-pulling today. When I started my day today, I noticed (with the stock tubes) a faint hum starting around 30 seconds after the amp was powered on before I started playing music. Everyone I had read about the Euforia was that it was "black". Yesterday was my first day of real/ substantial use. I didn't notice the hum yesterday, but I am not sure I had many moments with headphones on and music off. I would often take the headphones off while no music. If I were to guess, it was there the whole time, but hard to say. I/ we have spent the day back/ forth with ZRW0 working to track down what the heck is causing the issue. Notwithstanding our valiant efforts, the evil hum is still present and we thought to post to this group for any collective wisdom!

A synopsis of things tried. Most experiments are with the stock tubes, except for the 1 experiment with other tubes...

• I unplugged, let cool, and picked up the Euforia. I brought it in another room and plugged in (and nothing else) to the wall socket, then headphones into it, same hum. No DAC, RCA cables, etc. Nothing. Just Euforia in to wall, headphones into it. There aren't really even any other electronics in the room.
  
• Let it play for a few hours - see if it goes away.
• It has an EU AC chord. I am in the UK. I was using a EU to UK plug adapter. I replaced that with a standard PC cable in the Euforia. Same hum.
• Changed tubes for alt tubes (which ZRW0 used more commonly than stock). These had a louder hum in left ear. Possible the stock tubes are only left side. It is hard to say because it is more faint.
• Asked 17 yo son to see if he heard anything. Unprompted he heard the faint hum with the stock tubes. (I am not totally nuts!). He did say it was faint, but audible after the 30 second mark there was a clear change.
• The sound persists at 0 or any volume - invariant to volume setting.
• Put in room away from wifi
• Remove mobile phone from area
• Swap L<->R tubes
• FYI:
  • headset is a ZMF Eikon - 300 ohms.
  • the amp sounds good with stock tubes, while music is playing. It is not black when no music is playing. It can be clearly heard to go from true silent to hum ~30 sec post turning the amp on.
  • the amp sounds good with the other tubes, except when the music is quieter (can hear the hum) or when music is off (can hear hum).
  • the amp was shipped in 100% cottonwool. It was wrapped, double wrapped, bubbled, double boxed, etc. There were 8 tubes in the box, none of them broke. If the box was jostled harshly I would have expected one of them to broken. I think the shipping was 100% fine.

The most compelling evidence of an issue is heard with the alt tubes, which @ZRW0 used mostly. With them, the hum in the left ear is much more discernible. There is no way it was present and he didn't hear it. As such, I am trying to hunt down a solution prior to engaging Feliks, shipping the amp, etc.

Humbly; I am a noob with a tube. I will be happily embarrassed when this is sorted because of something dumb in my environment (he says hopefully!).

Any collective wisdom (flails even!) would be appreciated.

Best,
Chris

 

[hypnos1]

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.

Hmmm, mon ami...you obviously realise that such a blue glow is the only thing that just might possibly draw me out of retirement lol! ...not to mention the rave reviews I've come across . I will give this serious consideration Erwan, to be sure...in the hope our poor amps can work wonders once again with 'foreign' tubes!! (But I shall know who to blame if they blow my long-suffering amp to pieces!!! )....Sante...CJ

 

[LoryWiv]

Hello all

As some of you will know @ZRW0 was kind enough to sell me his pristine Euforia. He and I have been doing a bit of hair-pulling today. When I started my day today, I noticed (with the stock tubes) a faint hum starting around 30 seconds after the amp was powered on before I started playing music. Everyone I had read about the Euforia was that it was "black". Yesterday was my first day of real/ substantial use. I didn't notice the hum yesterday, but I am not sure I had many moments with headphones on and music off. I would often take the headphones off while no music. If I were to guess, it was there the whole time, but hard to say. I/ we have spent the day back/ forth with ZRW0 working to track down what the heck is causing the issue. Notwithstanding our valiant efforts, the evil hum is still present and we thought to post to this group for any collective wisdom!

A synopsis of things tried. Most experiments are with the stock tubes, except for the 1 experiment with other tubes...

• I unplugged, let cool, and picked up the Euforia. I brought it in another room and plugged in (and nothing else) to the wall socket, then headphones into it, same hum. No DAC, RCA cables, etc. Nothing. Just Euforia in to wall, headphones into it. There aren't really even any other electronics in the room.
  
• Let it play for a few hours - see if it goes away.
• It has an EU AC chord. I am in the UK. I was using a EU to UK plug adapter. I replaced that with a standard PC cable in the Euforia. Same hum.
• Changed tubes for alt tubes (which ZRW0 used more commonly than stock). These had a louder hum in left ear. Possible the stock tubes are only left side. It is hard to say because it is more faint.
• Asked 17 yo son to see if he heard anything. Unprompted he heard the faint hum with the stock tubes. (I am not totally nuts!). He did say it was faint, but audible after the 30 second mark there was a clear change.
• The sound persists at 0 or any volume - invariant to volume setting.
• Put in room away from wifi
• Remove mobile phone from area
• Swap L<->R tubes
• FYI:
  • headset is a ZMF Eikon - 300 ohms.
  • the amp sounds good with stock tubes, while music is playing. It is not black when no music is playing. It can be clearly heard to go from true silent to hum ~30 sec post turning the amp on.
  • the amp sounds good with the other tubes, except when the music is quieter (can hear the hum) or when music is off (can hear hum).
  • the amp was shipped in 100% cottonwool. It was wrapped, double wrapped, bubbled, double boxed, etc. There were 8 tubes in the box, none of them broke. If the box was jostled harshly I would have expected one of them to broken. I think the shipping was 100% fine.

The most compelling evidence of an issue is heard with the alt tubes, which @ZRW0 used mostly. With them, the hum in the left ear is much more discernible. There is no way it was present and he didn't hear it. As such, I am trying to hunt down a solution prior to engaging Feliks, shipping the amp, etc.

Humbly; I am a noob with a tube. I will be happily embarrassed when this is sorted because of something dumb in my environment (he says hopefully!).

Any collective wisdom (flails even!) would be appreciated.

Best,
Chris

You mention: "Remove mobile phone from area." For me, it was not a cellular mobile phone at issue but a cordless landline, even when base unit was at in another room. Removed all phones from the room where amp is --> problem solved! I hope it works out quickly so you can get back to just enjoying your amp.

 

[ZRW0]

Hello all

As some of you will know @ZRW0 was kind enough to sell me his pristine Euforia. He and I have been doing a bit of hair-pulling today. When I started my day today, I noticed (with the stock tubes) a faint hum starting around 30 seconds after the amp was powered on before I started playing music. Everyone I had read about the Euforia was that it was "black". Yesterday was my first day of real/ substantial use. I didn't notice the hum yesterday, but I am not sure I had many moments with headphones on and music off. I would often take the headphones off while no music. If I were to guess, it was there the whole time, but hard to say. I/ we have spent the day back/ forth with ZRW0 working to track down what the heck is causing the issue. Notwithstanding our valiant efforts, the evil hum is still present and we thought to post to this group for any collective wisdom!

A synopsis of things tried. Most experiments are with the stock tubes, except for the 1 experiment with other tubes...

• I unplugged, let cool, and picked up the Euforia. I brought it in another room and plugged in (and nothing else) to the wall socket, then headphones into it, same hum. No DAC, RCA cables, etc. Nothing. Just Euforia in to wall, headphones into it. There aren't really even any other electronics in the room.
  
• Let it play for a few hours - see if it goes away.
• It has an EU AC chord. I am in the UK. I was using a EU to UK plug adapter. I replaced that with a standard PC cable in the Euforia. Same hum.
• Changed tubes for alt tubes (which ZRW0 used more commonly than stock). These had a louder hum in left ear. Possible the stock tubes are only left side. It is hard to say because it is more faint.
• Asked 17 yo son to see if he heard anything. Unprompted he heard the faint hum with the stock tubes. (I am not totally nuts!). He did say it was faint, but audible after the 30 second mark there was a clear change.
• The sound persists at 0 or any volume - invariant to volume setting.
• Put in room away from wifi
• Remove mobile phone from area
• Swap L<->R tubes
• FYI:
  • headset is a ZMF Eikon - 300 ohms.
  • the amp sounds good with stock tubes, while music is playing. It is not black when no music is playing. It can be clearly heard to go from true silent to hum ~30 sec post turning the amp on.
  • the amp sounds good with the other tubes, except when the music is quieter (can hear the hum) or when music is off (can hear hum).
  • the amp was shipped in 100% cottonwool. It was wrapped, double wrapped, bubbled, double boxed, etc. There were 8 tubes in the box, none of them broke. If the box was jostled harshly I would have expected one of them to broken. I think the shipping was 100% fine.

The most compelling evidence of an issue is heard with the alt tubes, which @ZRW0 used mostly. With them, the hum in the left ear is much more discernible. There is no way it was present and he didn't hear it. As such, I am trying to hunt down a solution prior to engaging Feliks, shipping the amp, etc.

Humbly; I am a noob with a tube. I will be happily embarrassed when this is sorted because of something dumb in my environment (he says hopefully!).

Any collective wisdom (flails even!) would be appreciated.

Best,
Chris

Just to add to Chris comment, I've been using as much 6SN7/6ASG7 and EL tubes on this amp. For the EL tubes, I mostly used EL38/EL32 combo.
The EL11 and EL39 were barely used as I found in love of my new amp shortly after the acquisitions of those. They are both less than 50h usage for what concerns me hence near NOS (all bought as NOS).

What really puzzles me is that constant humming Chris is hearing whether the stock tubes or the El tubes are used. I never got any hum with any of those tubes on my side...
The Euforia and the tubes were not used for about 1,5m before I sent them to Chris.

 

[chrisdrop]

You mention: "Remove mobile phone from area." For me, it was not a cellular mobile phone at issue but a cordless landline, even when base unit was at in another room. Removed all phones from the room where amp is --> problem solved! I hope it works out quickly so you can get back to just enjoying your amp.

Tx LW. I appreciate the note. No land line phones here (sadly in this case). Just got done powering down the wifi and computers in the whole house! No luck yet. Going to try going across the house and see what happens there..

 

[DecentLevi]

@chrisdrop here's 4 more suggestions. And for the first two you'd need to make an extra purchase but they may be well worth it, especially the 2nd one:

@mordy I think it was you who recommended some sort of high-temperature adhesive tape that can reduce hum on tubes?

You can also try a power conditioner, or more compact isolating power strip. Some members here recently had gained positive results with power conditioning - sonic improvements and as these isolate from EMI / RFI this may well solve the problem, as well as improve the sound. I have their top model IT Reference 15i and though I've still yet to do a thorough A/ B, the brief test I did revealed a true night / day improvement for all aspects of the sound on the Euforia. Here are their more compact options as power strips, however these may be only for 120v. And their AC-210A E is for 240.
https://www.furmanpower.com/products/compact-power-120v

Touch one of the RCA outputs on the back of the Euforia. If the hum stops, then just wrap a wire around that RCA socket to a ground that may work such as a windowsill or out of the window to a large nail in the dirt, depending on which works best.

You can also try other tubes to see which have less hum.

PS - you should be free to post pix now

 

[mordy]

@chrisdrop here's 4 more suggestions. And for the first two you'd need to make an extra purchase but they may be well worth it, especially the 2nd one:

@mordy I think it was you who recommended some sort of high-temperature adhesive tape that can reduce hum on tubes?

You can also try a power conditioner, or more compact isolating power strip. Some members here recently had gained positive results with power conditioning - sonic improvements and as these isolate from EMI / RFI this may well solve the problem, as well as improve the sound. I have their top model IT Reference 15i and though I've still yet to do a thorough A/ B, the brief test I did revealed a true night / day improvement for all aspects of the sound on the Euforia. Here are their more compact options as power strips, however these may be only for 120v.
https://www.furmanpower.com/products/compact-power-120v

Touch one of the RCA outputs on the back of the Euforia. If the hum stops, then just wrap a wire around that RCA socket to a ground that may work such as a windowsill or out of the window to a large nail in the dirt, depending on which works best.

You can also try other tubes to see which have less hum.

PS - you should be free to post pix now

@chrisdrop here's 4 more suggestions. And for the first two you'd need to make an extra purchase but they may be well worth it, especially the 2nd one:

@mordy I think it was you who recommended some sort of high-temperature adhesive tape that can reduce hum on tubes?

You can also try a power conditioner, or more compact isolating power strip. Some members here recently had gained positive results with power conditioning - sonic improvements and as these isolate from EMI / RFI this may well solve the problem, as well as improve the sound. I have their top model IT Reference 15i and though I've still yet to do a thorough A/ B, the brief test I did revealed a true night / day improvement for all aspects of the sound on the Euforia. Here are their more compact options as power strips, however these may be only for 120v.
https://www.furmanpower.com/products/compact-power-120v

Touch one of the RCA outputs on the back of the Euforia. If the hum stops, then just wrap a wire around that RCA socket to a ground that may work such as a windowsill or out of the window to a large nail in the dirt, depending on which works best.

You can also try other tubes to see which have less hum.

PS - you should be free to post pix now

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.

 

[DecentLevi]

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

 

[hypnos1]

Tx LW. I appreciate the note. No land line phones here (sadly in this case). Just got done powering down the wifi and computers in the whole house! No luck yet. Going to try going across the house and see what happens there..

Hi chris...this really is too cruel! And the bane of existence for quite a few audio enthusiasts, especially tube amp lovers alas!

When not down to the tubes, there's a whole host of things in one's mains electricity chain that can be the cause, from 'ground loops' to 'phones and 'fridges.

1. Anything electrical in the house that's running at the same time needs to be switched off, to eliminate them as cause...including routers and mobile 'phones.
2. If no change, try the amp in another property...preferably in a different vicinity.

Assuming all cables, plugs, connections are 100% and hum remains, then it's possibly the mains supply itself that's the cause...either in the house wiring or much further back in the supply! I personally always had a slight hum that went when the music signal kicked in, and only went completely when I used a PowerInspired Mains Regenerator, then an AirlinksTransformer Conditioning Balanced Mains Transformer. I would recommend the latter, if interested - I myself splashed out on the one with added advanced filter system, but this one should be perfectly fine and a good bit cheaper : https://airlinktransformers.com/product/conditioning-balanced-power-supply-cbs2000-240

I really do hope you soon find the cause and solution chris...let us know how things go...GOOD LUCK!