M4 has loud pop changing channels (tube brand specific)

[mfred]

I have a Rocktron VP-4 single channel preamp that was upgraded by Egnater. It's now the same as a single channel Egnater M4. I've been doing a bunch of tube swapping lately and noticed something very strange. Whenever I change out the upper chasis tube on the M4 to something other than a Sovtek, Ruby, or Groove Tube R, I get a horendous pop when changing channels. I absoluely love the tone I get from the new Genelex Gold Lion 12AX7 in this position but the pop drives me crazy. Has anyone else come across this? Tungsols and JJ's in the upper position also cause this pop. Is there anything I can do to the M4 so that I can run the Genelex tubes in it. Anybody?

 

[bbaug14]

Contact Bruce directly. He's probably the only person that can answer this with any sort of confidence. Also, he normally prefers to be asked about questions like this rather than getting an answer from someone on a forum and then doing then doing something that might be harmful to your amp.

 

[m0jo]

Yep, definitly check in with Bruce.

 

[bruce egnater]

Did you ever resolve this noise issue?

 

[Metz]

I’m getting the same issue with my brand new syn 2 when switching from channel 4 to 3 on the synergy midi switcher pedal .