when designing my mixer project I resorted to use conventional opamp circuits. First I had a high voltage class A opamp in mind (think SPL), then i found that this would only give me headroom above 24dBu - so with my AD/DA converter this is of no use... then I looked into lowering the THD and noise of my design to allow for the best performance. this is nicely achievable with todays modern opamps, their measured specs are really excellent. but hey, the neg feedback involved in these is really large. I looked into the voltage follower buffers as I need only little gain and could put all gain I use in one discrete stage at the input, but again, will it sound any better?
then there is this large group of DOA API (et. al) users out there. by todays measurement standard a medium quality opamp, but it appears to sound nice for some of you....
then there is the quite large fraction of users that have buffers and discrete gain stages in the design. lower overall feedback appeals to me, I never known why, maybe because the feedback always is about canceling THD, but is it also about getting good sound?
so two questions:
any experiences with buffers, discrete class A, high voltage opamps? why (can) they sound better? did you A / B some designs?
does the measured specs really reflect the optimum regarding nice sounding gear? I know we sometimes like the added sound - so should we aim for more distortion then the 0.005% you can get with these modern monsters?
would be glad to hear from your experiences, but hey, no need to bash at each other, no flame war, ok...
PS: I think I will have to build my mixer with a 'less feedback' topology to test A vs. B - kind of have to know the sound that could have, huh!