Wright Sound AG Phono Preamp questions

I have a wright sound ag phono preamp, main chasis tube complement is 1 x 12au7, 2 x 12ax7, and 2 x ecc99. My quesiton is are the ecc99's part of the original design. When I tap my finger on the ecc99's they ring in the speakers (in fact the chasis and everything connected to the pre can cause a slight high freq ring and I noticed it in the music at higher volumes). My thought was that the tubes must be microphonic but I wasn't even sure if these are the correct tubes for the design (my AG pre was built in 2002). I rolled several au7 and ax7's and I am sure it is not a problem with these tubes. I had a pair of 12bh7's which without knowing if these are a correct sub for the circuit tried them briefly, you can still hear a tap when tapping the tube but not the high freguency ringing sound. If anyone has this pre and can help with any info it would be appreciated, thanks!
Hi: I have an AG phono but the configuration is slightly different than yours. I bought mine directly from George Wright since I only lived 25 miles from him. Mine uses 4 12ax7s and one ecc99/12bh7. You have the correct tubes. I haven't experienced any of the ringing you have. Do the tubes check out on a tester? George Wright advised that you should put both the preamp and the power supply "...on a hard, stable surface to avoid microphonics(vibration pickup) common to all vacuum-tube electronics." This is a great phono pre so I hope you solve the problem. Rob.
Sounds like a microphonic tube to me. Swap it out and see what happens.
Thanks for the info, it is not really a problem and only noticeable at high volumes and then barely. Rob, that is interesting that there is this variation in tube complement (mine uses two ecc99's as the input pair and yours with a single ecc99 for the output, my version uses the 12au7 as the output). Does anyone know if there were manuals or schematics for these?
George Wright never released any schematics for his gear.
Someone suggested that it is probably a prototype, the serial number is 2002 and the mfg date is 5/02. Really a nice preamp,