Audio Research VT100 MKIII Tube Replacement

It's a stereo? To save money that is a way to do it. At the time 6 matched valves vs pairs was a lot more expensive.. Not now... To many NEW production valves out there at really good prices.. BUT I'm sure it is a way that works well for their units.. 

After 55 yeas of valves.. I match valves per rail.. pretty simple.

The signal valves you're stuck.. No idea WHY people use valves like that.. Very limited valve manufactures too.. I call it the TV tube mentality. LOL what do I do with these old TV valves.. I know, I'll voice a power amp.. No idea why.. BUT I got 12,000 of them in a container for 50.00 usd.. Cary does the same weird stuff.. 12BH7, I mean WTF is that..
12AX7, 6922, 12AZ7, but 12BH7.. TV TUBE.. 

Regards..

Pretty sure the MK III is easier to bias than the MK I and II models but I’d take it to a qualified tech as the VT100 is a bear to setup. Not to scare you but I’m sure you don’t want to blow your amp up. Unless ARC did something different to the circuit you have to bias both the input and output. I’d call and talk to ARC before you pop the lid. Definitely not an amp for a newbie to bias. Good luck.

mk3 easier to bias than earlier versions - still need multimeter and hook probes (and the long blade screwdriver)... but that is the power tubes

to bias the input tubes is tough... best to send to factory as much as a pain and major cost that may be... good news is once done the small signal tubes will be good for years and years

and to the earlier point... +1 yes 6h30's all the same...

I send my VTM200's in to AR every so many years.  They take care of everything.  Excellent service gets best performance.