cmb2001

I meant in your opinion is it possible the difference between 6l6 and 5881 tubes can physically damage the internal components of the amp or if I put sovtek 5881 tubes as suggested the master volume should work?

ill double check on the actual tube number tonight. I know its hard to say without the amp in front of you, but in your opinion, if they are 6l6 could components in the amp be damaged or could replacing the 6l6 with sovtek 5881s remedy the problem?

1. The amp is not with me, I do remember they are ruby 6l6 tubes on output, 12ax7s are unknown brand at this time, I was told it was freshly tubed and biased about a month ago. 2 & 3: the cab is 16 ohm and a speaker cable is in the 16 ohm tap. the amp sounds good its just the master volume does nothing. the channel volume controls the volume on active setting.

Hi, Preface: I kind of browsed the forum but couldn't find anything matching my problem. I bought a Spider Valve HD100 Mk1 to use while my main amp is being serviced. The seller went through the paces with the amp and informed me the master volume didn't work. being as it was super loud and controllable through channel volume I still bought it. I plan on keeping it as a backup so id like to see if I can fix this issue. Issue: Master Volume sounds to be at about 7 id say compared to other 100 watt amps ive used. I can turn the knob from 0 - 10 and no change in volume, no static, zero response. The volume can be controlled by the channel volume but switching presets will blow ears out if not careful. Could this be remedied by a simple pot change or could it be something more. Looking on suggestions on troubleshooting the circuit maybe? I have some electronics experience so I know about high voltages etc going into the amp. Thanks