Rolling Mullard 6DJ8 into GE 5670 Application

The E88CC is capable of adding airiness, and separation between performers.

They are also adept at allowing the note and vocal to have a perceivable envelope.

They don't overwhelm in the Bass area, the Bass is present, but will be well defined and have an attractive decay.

Any valves I have used during Tube Rolling, that have been hard on the ears in comparison to other used Valves are removed immediately, I can't see how they are to deliver the standard on offer from others being trialed. 

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.

Yes, the parameters that work for a designed 6SN7 would not tend to damage an E88CC.  But you could get some improvement by increasing the plate current, which has to be done in such a way as not to exceed the recommended plate dissipation for an E88CC, which might mean just lowering the plate voltage.  Best to leave well enough alone.  Many would argue that the 6SN7, as was, is one of the lowest distortion triodes ever made.