Tube rolling - 12AU7 to 6922 adapter


I thought I’d transfer this thread over to this discussion category from tech talk. I recently changed preamps - from 12AU7 circuitry to 6922. Yet, over the years, I’ve accumulated a sizable stash of NOS 12AU7’s - some of which I really enjoy.

At @kdude66’s suggestion, I purchased these 12AU7 to 6922 adapters. My main concern was damaging my pricey new preamp. No problem. It’s sounding kind of great! These adapters are built very well using real ceramic sockets. They fit snugly in the 6922 sockets. For those using components with 6922 tubes, this opens up a whole new world of 12AU7 tube-rolling possibilities. The only drawback is that they add about 7/8" height. So, I need to build a riser to raise the preamp lid. It should be simple.
steakster
I did not know that could be done. A 12 type tube is 12 volts and a 6 type tube is 6 volts! Are you sure you won’t damage the preamp?
yogi: all that does is jump pins 4 & 5 and connects pin 9 to ground to put 6.3 volts in parallel to the 12AU7. The tube can run at either 6 or 12 volts.

op: There should not be an issue running a lower gain tube, however the circuit is optimized for the 6922 and the 12AU7 may be operating outside its sweet spot. Try listening to a 6922 to see if there is a difference.
Three preamp's ago was ECC88 based.   That started my NOS collection of 6922's, 6DJ8's, 6N23P's, etal.   Two preamp's ago was ECC82 based.  That started my NOS collection of 12au7's, 6189's, CV4003's, etal.  Now with these adapters, I can use any of them with my current preamp.  After weeks of experimenting, everything is working optimally.   The sonic signature of each tube-type is still retained.   Of course, preference is very subjective.