Hello,
2 x SS V5 in LPF stage caused sort of a "radio" noise while moving the volume knob between 90 - 100%, though I couldn't see any oscillations on my scope. Sound was very good, not much of a difference comparing V5 with MUSES02, but without a proper A/B test I can't decide which one would be better.
I believe now I'm using 2 x V5i in LPF and 2 x V5i in VAS and sound is very good, maybe a bass is a bit overemphasised on the headphones, but this is a subjective test anyway.
Besides the 4 x MUSES01 in I/V (you already have those) I can only recommend 2 x MUSES02 or 2 x V5i in the LPF stage; optionally you could do the same in VAS stage, but to be honest difference will not be night & day, so feel free to try this only if you really have the money for and really-really want to try some mods.
Regarding to my other mods I've did:
- if you don't have hum on your headphones then I see no reason to shield the transformer
- if you have a scope then please measure the -12V rail and see if you can identify those spikes I was speaking about; if not, there's no reason to move further with -12V ground loop mode
- without a scope I see no reason to move on with replacing power regulators or by adding a dedicated +5V to PCM1795 DAC chips
Also, replacing power regulators, resolving ground loops and adding a new +5V PSU for the DACs is extremely "intrusive" and could damage the PCB and electronic components, so please take care when doing some of these mods! The least intrusive mods could be: increasing PSU caps filtering value (either by replacing the original caps, either by adding more caps in parallel) and adding more decoupling caps nearby the 2 DACs (WIMA MKP, but also tantalums should help).
The most improvements I've noticed when I've upgraded default I/V opamps to 4 x MUSES01 (details, clarity, soundstage, more relaxed sound), but also when I've added a separate +5V power source for the 2 x PCM1795 DACs (the original E1 had a "grainy" sound and a bit fatiguing too). I had access to 2 identical Essence One to do A/B test and an additional audiophile to help out with the tests.
Regards,
Raul.