2. amps-preamps
  3. 134710-89202

Question for tube aficionados

I have a vintage Conrad-Johnson PV 11 preamp.
 I’ve always re-tubed it  with the cheapest tubes from Tube Depot (e.g. Electro-Harmonix 12AU7 and 12AX7, Sovtek 5751 and the like.). I’ve been very happy with the sound.
 My question is:
 Would it be worthwhile to spend more money on more exotic tubes?
  Would there be any appreciable difference in the sound?
 I’m powering the system with NuForce Reference 9 V3 monoblocks.
128x128rvpiano

Showing 2 responses by johnss

johnss
564 posts
 
I used to have both the PV11 and PV12. NOS tubes did sound better, but if memory serves, seem to recall in both preamps the tubes were run in a current starved condition. You may want to measure the current/voltage flow through the tube. I dropped the plate load resistors and got much more open sound, but do not remember the values.

Still wish I had my PV5...that preamp made real music.

best.
johnss
564 posts
 
I owned the PV5, PV8, PV11 and PV12 over the years. Going from memory, seems the later versions starved the tubes a bit. before you start serious tube rolling, may want to measure the plate and cathode voltages and see what there are, then calculate the current going through the tube. On my PV12, there was less than a milliamp, so changed out the plate and cathode resistors to at least get the current up to a milliamp. sounded much more open and less constrained.

The PV5 I wish I had never sold...did not have the highest resolution, but was such a musical sounding piece.

best
J
More to discover