Hi Rick,
I tend to agree with John. There is not that much info on VAC products and by experience not a lot of audiophiles are well acquainted with this excellent brand.
I have a Standard LE preamp. It was designed back when your CPA MKIII was made available on the market. If I presume the same sonic signature was implemented in both preamps, I would then conclude that your unit is quite transparent with a lot of focus and details. Imaging would be it's main strength but warmth would be its downside. Am I right ?
If so, I would immediately say that your unit must very sensitive to tubes rolling as mine is. And both preamps seem to have the same tube complement. John did give you good basic recommendations. You could also have a look at Joes tube lore for more info on 12AX7 and AU7 tubes:http://www.audioasylum.com/scripts/d.pl?audio/faq/joes-tubes.html.
Personnally, I prefer a warm sound so black plated 5751s NOS Sylvania or GE JHS combined with RCA Clear tops or Valvo in the AU7 positions did the job on my Standard LE. Radio technique AU7s were an excellent alternative and not very expensive. Generally speaking, I found 12AX7 tubes had too much gain and were too bright for my taste in my Standard LE.
Hope this can help you !
Regards !
I tend to agree with John. There is not that much info on VAC products and by experience not a lot of audiophiles are well acquainted with this excellent brand.
I have a Standard LE preamp. It was designed back when your CPA MKIII was made available on the market. If I presume the same sonic signature was implemented in both preamps, I would then conclude that your unit is quite transparent with a lot of focus and details. Imaging would be it's main strength but warmth would be its downside. Am I right ?
If so, I would immediately say that your unit must very sensitive to tubes rolling as mine is. And both preamps seem to have the same tube complement. John did give you good basic recommendations. You could also have a look at Joes tube lore for more info on 12AX7 and AU7 tubes:http://www.audioasylum.com/scripts/d.pl?audio/faq/joes-tubes.html.
Personnally, I prefer a warm sound so black plated 5751s NOS Sylvania or GE JHS combined with RCA Clear tops or Valvo in the AU7 positions did the job on my Standard LE. Radio technique AU7s were an excellent alternative and not very expensive. Generally speaking, I found 12AX7 tubes had too much gain and were too bright for my taste in my Standard LE.
Hope this can help you !
Regards !