Which of these do you think are the best or what are in general terms, the differences?
1. Mullard M8161/CV4015
2. Mullard M8100 / CV4010
3. Voshkod 6ZH1P-EV
I´ve heard the Mullards on my LDMKIII with HD650 and because the HD´s are kind of laid back and the Mullards too, sound was a bit muffled.
The Voskhods were nice without initial burn-in of 120hrs when they apparently do start to shine. These are more forward than the Mullards and have a nice balance over frequency range but a bit pronounced highs.
So the best way would be to combine driver tubes with the headphone you are using. If it´s a very bright HP then use the Mullards for example.