I've got the same problem. Please let me know what you find out. I've bought some NOS Telefunkens (which were touted by their collector/seller as being as quiet as I could hope to obtain). While they did lower the "perceived" background noise "ever-so-slightly" compared with the factory-stock Sovteks, their gain was also correspondingly slightly lower. Also, when the output signal is RTSA'd in A/B comparisons (Sovtek in the L chanel, & Telefunkens in the R ch), the German Telefunkens' background was barely lower in the treble freqs than the Rusian tubes, but barely higher in the bass freqs. So it roughly averaged out (but red-shifted in spectrum). I have been told by several Rhea experts that a noise penalty is just the price we have to pay for a phono pre whose amplification is simultaneously pure-triode, class-A, OTL, zero-feedback, & high-gain. Still, like you, I need less noise, so still searching for quieter tubes. The Rhea's build-quality & features are so good, its sonic texture is so liquid, its tonal balance is so neutral, its freq & dynamic ranges are so wide, & its phase-coherence is so linear...That I don't want to give up on this superlative product. I hope that the tube rush can be reduced by @ least half of what I now have.
RiP
richard.plenge@navy.mil
