Bias Rite readings on Mark IV

[Paul Secondino]

Rabies,
It is true that you can install well matched tubes in any amp and see what appears to be not so well matched tubes. All 4 tube sockets can and usually will flow current slightly differently than each other.

However, my tech did some minor mods to my 68 Fender Showman Reverb to balance out all the sockets for a very even bias across the board. This isn't really a tone or sustain thing but actually makes the amp run more efficiently and makes it quieter. The amp is almost quiet at full volume

A good idea for you is to go to a decent tech with your bias rite and have him bench mark it for you.My tech compared mine to his $300.00 probe and my bias rite was almost dead on reading cathode current as his probe..

 

[HalfDeaf]

rabies wrote

I've been eyeing some VHT's and Laney's recently...

rabies - sometime I'll write up a mkiv vs. vht D60 and do a thorough comparison. They are COMPLETELY different amps. You should definitely find one and try it out. I miss the channel switching and metallica-grind of the mkiv. But, my stress level has gone way down with the vht - its so easy to get great tone. And the tubes are stock sovtek and chinese. I would have never thought cheap tubes could provide such lush distortion - I mean really floral and dynamic. Just goes to show that circuit design and transformers play a major role in tone, not just fancy tubes.