[Salmonad]

One thing must also be mentioned.
According to Feliks, putting 4 KT88 tubes on the Euforia is not intended.

Feliks recommends using the tubes listed in the manual.

Of course it is possible to use 4 Kt's, but I think that was the weakness of the Euforia if I remember the old reports correctly.
This is also due to the fact that they are quite close to the upper limit in terms of amperage.

I would be careful with the hi-fi dealer, if he knows that you are doing things that are not in the manual, he can refuse to repair them.
Even an exchange if you are still in it.

Take out two KT tubes and replace them with a couple of 6SN7 and see if it improves.

What you should also keep in mind in the future is that a set of 4 is also matched.
It can be that 1-2 tubes put too much strain on the bias control.
Usually one tube is enough and the drama is perfect.

You can check if one of the tubes hums when there are two 6SN7 in the front.
Plug in two Kt 88 and leave them in for 30 minutes, then switch them off, wait a bit and put in the next pair.
If only one channel is humming, mark the tube.

By the way, I also use adapted 6V6 tubes,
They also hum a little but not so much that it interferes with the music.
Of course you shouldn't do it but some 6V6 are better than 6SN7.

Tried this but didn't hear any improvement...even without any KT88s

 

[Salmonad]

The hum was always there from the beginning...I thought it had something to do with burn in. I've only just changed the tube to KT88s recently. I bought the Eurforia about 8 months ago and I'm wanting to upgrade to the Envy but this is making me a bit unsure about my next steps.

 

[incredulousity]

One thing must also be mentioned.
According to Feliks, putting 4 KT88 tubes on the Euforia is not intended.

Feliks recommends using the tubes listed in the manual.

Of course it is possible to use 4 Kt's, but I think that was the weakness of the Euforia if I remember the old reports correctly.
This is also due to the fact that they are quite close to the upper limit in terms of amperage.

I would be careful with the hi-fi dealer, if he knows that you are doing things that are not in the manual, he can refuse to repair them.
Even an exchange if you are still in it.

Take out two KT tubes and replace them with a couple of 6SN7 and see if it improves.

What you should also keep in mind in the future is that a set of 4 is also matched.
It can be that 1-2 tubes put too much strain on the bias control.
Usually one tube is enough and the drama is perfect.

You can check if one of the tubes hums when there are two 6SN7 in the front.
Plug in two Kt 88 and leave them in for 30 minutes, then switch them off, wait a bit and put in the next pair.
If only one channel is humming, mark the tube.

By the way, I also use adapted 6V6 tubes,
They also hum a little but not so much that it interferes with the music.
Of course you shouldn't do it but some 6V6 are better than 6SN7.

I thought he had problem with stock tubes too.

Euforia gave me a tiny bit of hum with KTxx (mostly 77), when tubes were new.

One should always use external power when rolling nonstandard tubes that approach the upper limits for heater current for the amp. Safest to consider the drivers and powers separately in this regard too.

On Envy, I’m even more conservative, and use external power with any driver rolls than bone stock 6SN7 variants, though a lot of tubes should be in spec. Feliks hasn’t published heater current limits for Envy drivers at all, so stay safe.

Also, as there are so many good options, I really advocate KTxx use as power tubes. They work ok as drivers on Euforia, but less well on Envy, though they do function correctly.

It bears repeating that 12au7 at 6.3v on adapters work very well, sound good, and are dirt cheap for current ones.

Mullard>GL>PSVane=TS. PSVane may rise, but like their 6SN7 counterparts, seem to need 200hrs burn in.

 

[ThanatosVI]

It bears repeating that 12au7 at 6.3v on adapters work very well, sound good, and are dirt cheap for current ones.

Do you use them in yours?
Since my Octave also uses 12au7 this would be like the best driver tube type to invest in for me

 

[incredulousity]

Do you use them in yours?
Since my Octave also uses 12au7 this would be like the best driver tube type to invest in for me

In Envy currently, yes.

The adapters are dirt cheap as well from the usual eBay source.

Also, if you have external power, you can burn them in at 12V with the amp turned off. They hum at 12 V with the amp on, so not advised. I still haven’t gotten to making adapters from tube power to Hypsos, but actually thing there may be fun in voltage tweaking on my drivers. I have a set of weird Shuguang red base WE+ type 6SN7 that I actually want to undervolt.

 

[ThanatosVI]

In Envy currently, yes.

Which 12au7 are you using?

I also take pms if you don't want to derail the thread

 

[iFi audio]

Try iFi DC Blocker and GND blockers.

It's worth giving one of these a shot. DC Blocker should remove any residual DC offset usually heard as a transformer hum, while GND defender may help with buzz related to grounding. Thanks!

 

[mgsu]

I have recently installed quad KT88 on my Euforia AE. I am hearing a hum that I never heard before using my ZMF Vérité Closed. Is this normal or is there a ”trick” I’m missing.
It has nothing to do with my chain since the hum is there even when not connected to anything. The tubes have been burned in for at least 100 hours.

Any tips?

In case of a ground loop, try to disconnect from back end to front end all devices step by step from your chain an see if the hum disappear. Beginn to disconnect your streamer, than your ddc, dac and so on. Always keep the amp on and listen if the hum disappears while you disconnect components.

 

[Salmonad]

In case of a ground loop, try to disconnect from back end to front end all devices step by step from your chain an see if the hum disappear. Beginn to disconnect your streamer, than your ddc, dac and so on. Always keep the amp on and listen if the hum disappears while you disconnect components.

Unfortunately the hum is without the chain.

 

[Salmonad]

It's worth giving one of these a shot. DC Blocker should remove any residual DC offset usually heard as a transformer hum, while GND defender may help with buzz related to grounding. Thanks!

Is there any preference which I should try first?
And
With the DC Blocker I presume I would take a SQ hit...right?

 

[iFi audio]

Is there any preference which I should try first?

It depends on humm you're experiencing. If transformers in your amp make that sound, then DC Blocker is the one to try. If you hear buzzing in your speakers or headphones, then GND Defender is worth trying out.

With the DC Blocker I presume I would take a SQ hit...right?

Not necessarily, the feedback we got thus far about our DC Blocker is that it's efficient in removing one specific type of hum and... that's it . Thanks!

 

[Salmonad]

OK everyone…I feel really stupid now! I found the problem with my zero volume hum…2 mains power cables.
Unfortunately I tried both when experimenting in different room. Both of them are bad. Thats what you get for making your own „HiFi“ power cables.
I am now a very happy man.
Nevertheless, this is the first time I‘ve posted such a problem in the community and it was wonderful to see how people really wanted to help. THANKS.

 

[incredulousity]

OK everyone…I feel really stupid now! I found the problem with my zero volume hum…2 mains power cables.
Unfortunately I tried both when experimenting in different room. Both of them are bad. Thats what you get for making your own „HiFi“ power cables.
I am now a very happy man.
Nevertheless, this is the first time I‘ve posted such a problem in the community and it was wonderful to see how people really wanted to help. THANKS.

Would you be so kind as to share how you “misconstructed” your power cables to create this problem? Everyone can learn from your experience. Thanks!

 

[Salmonad]

Would you be so kind as to share how you “misconstructed” your power cables to create this problem? Everyone can learn from your experience. Thanks!

The cable I used I have used in the past with no problems. However this has been in the studio on a dedicated circuit. However the differences this time are:
- Plugs/copper connections from Amazon
- Shorter lengths
I‘m not saying that these are the reasons. These are simply things that come into mind. I now have stock power cables back on my Euforia and my Mola Mola Tambaqui.
I am open to any suggestions for future power cables under 300. (I don‘t have any experience with expensive power cables and am worried about snake oil.
Blow a picture of my cables..

 

[iFi audio]

The cable I used I have used in the past with no problems. However this has been in the studio on a dedicated circuit. However the differences this time are:
- Plugs/copper connections from Amazon
- Shorter lengths
I‘m not saying that these are the reasons. These are simply things that come into mind. I now have stock power cables back on my Euforia and my Mola Mola Tambaqui.
I am open to any suggestions for future power cables under 300. (I don‘t have any experience with expensive power cables and am worried about snake oil.
Blow a picture of my cables..

Thanks for sharing and just to double-check, you did continuity tests on these cables and everything was okay there?