Need VTA preamp help

All VTA tube preamp with VTA 5 line board and 6 phono board, regulated PS, toroid transformers.
Hi eff speakers, tested also on lower eff speakers same results.
Problem:
Slight but annoying hiss in left channel
Same with any source or none.
Swapped matched old EH 12ax7 front to back- no difference.
Same any vol setting 0 to half way, which would be very loud. Past half hiss does increase.
Thought I would try new set of tubes, everyone says hiss is tubes.
Put in new genalex gold lions 82s, matched, low noise and hiss is much louder at same vol setting as EHs.
Pre has been back to Roy, super fellow has gone above and beyond trying to sort this out. Still has hiss.
Any suggestions GREATLY appreciated. Driving me nuts. Thanks, Doug

How discouraging. Good luck with that. The last one was never heard from. I so wanted to build one.

dougm216 wrote:All VTA tube preamp with VTA 5 line board and 6 phono board, regulated PS, toroid transformers.
Hi eff speakers, tested also on lower eff speakers same results.
Problem:
Slight but annoying hiss in left channel
Same with any source or none.
Swapped matched old EH 12ax7 front to back- no difference.
Same any vol setting 0 to half way, which would be very loud. Past half hiss does increase.
Thought I would try new set of tubes, everyone says hiss is tubes.
Put in new genalex gold lions 82s, matched, low noise and hiss is much louder at same vol setting as EHs.
Pre has been back to Roy, super fellow has gone above and beyond trying to sort this out. Still has hiss.
Any suggestions GREATLY appreciated. Driving me nuts. Thanks, Doug

Maybe a noisy resistor?


Steve