Rolling Mullard 6DJ8 into GE 5670 Application

Prior to posting I did reach out directly to Maverick Audio and also Andrew at Sparkos Labs since I put his op amps in it.

When I purchased the DAC it has the GE JAN 5670 tube (upgrade from Maverick), then I rolled in the Western Electric 396A that some recommended as an upgrade along with the Sparkos Labs op amps that were a significant upgrade.  I didn't hear much if any difference with the switch from GE to WE tubes.  I think the tube is a buffer in the DAC, so it's very possible that the Mullard would yield little difference as well.

I do have Focal speakers, so some would consider them to be bright/harsh which may be why the Mullard sound great in my Pathos.  The person that recommended and sold them to me was very clear that his preference is very warm and the Mullard were the warmest he could find.  When I made the switch the improvement sort of defied logic in that it was a warmer sound, but also more detailed and just an improvement in every way over the hodgepodge that I had before.  I've briefly tried some of the "stock" tubes (can't think of the name off hand) and they were awful and came back out almost immediately.

The adapter was delivered last night and I was able to do the tube swap this morning.  It definitely sounds different and my initial response was positive, but I'm becoming less impressed as time goes on.  I'll give it a few weeks and then switch back and see how it feels.

@lewm - Thanks for the information.  I don't know if it matters, but the adapter is allowing me to use an E88CC tube in a 6SN7 application which is the opposite scenario.

For what it's worth, it's been running since yesterday morning and so far nothing bad has happened...

If anyone is interested in the results so far, there certainly seems to be some added clarity, instrument separation, and air around the highs, but the bass also seems to have taken a backseat with some harshness in the upper bass and upper mid ranges.  I don't find it very satisfying when a change yields very mixed results.  I'll let them ride for a while longer and then switch back and see how things sound.  I think I've lost from PRAT with the change in bass presentation.

Best of all, nothing has burned down yet...

After putting the 396A tube back in and having mixed emotions about the results, I talked myself into taking a different approach all together and scratching another audiophile itch.

I've purchased a used Denafrips Ares II DAC that I hope will be a clear upgrade for my system.  I did some reading to reinforce my expectation bias, so I've done what I can!

The Maverick Audio TubeMagic D2 DAC is clearly an entry level product (<$250) and marketed as a desktop DAC.  With the Sparkos Labs op amps I believe that it outperforms it price point, but anticipate that the Denafrips will be a step up.

The results are in and the Denafrips Ares II DAC is a clear upgrade for me.

It makes sense as I auditioned the Maverick Audio TubeMagic D2 DAC against the Schiit Modi Multibit and determined that the Modi sounded the same as the tube output on the D2 and I preferred the solid state output.  I then upgraded the D2 with Sparkos Labs op amps which was a clear upgrade with the result being that I then preferred the tube output.  The Denafrips Ares II is a clear upgrade to the modified D2 and is commonly compared to the Schiit BiFrost (or Gungnir), so seems to align with what would be expected.