Using contact cleaner in tube sockets

jea48

I have always wondered why ARC neglected to mention in the owner manual that came with the VT50, VT100, Vt100 mkll, and VT200 that when replacing the small driver and input signal tubes they would need to be biased ... Biasing the 6922 tubes is not for the novice. Lethal DC voltage is present at points the multimeter probes will be connected.

An owner's manual and a service manual are two different things. As you note, biasing the 6922 tubes is not for a novice. The owner's manual does clearly state: "Refer servicing to your authorized Audio Research dealer or other qualified personnel."

cleeds,

"Refer servicing to your authorized Audio Research dealer or other qualified personnel."

As a rule retubing an amp should not require sending it back to the factory or to a qualified manufacture service center.

ARC should have made mentioned in the owner manual retubing the 6922 tubes required they would have to biased.

There used to be pictures on the Net showing VT100s with burned circuit board traces damage. Just a guess many were due to the user just installing new power tubes and 6922 tubes thinking they only needed to bias the power tubes. If you read the manual what would think?
Look no further than the OP of this thread.

For several years Upscale audio would not sell tubes to owners of ARC VT series power amps. Guys were blowing power tubes and damaging their amps and blaming it on the tubes Upscale audio sold them.

jea48

As a rule retubing an amp should not require sending it back to the factory or to a qualified manufacture service center.

Neither of these is a requirement for the VT-100, so I'm not sure what your point is.

ARC should have made mentioned in the owner manual retubing the 6922 tubes required they would have to biased.

Again, an owner's manual is not a service manual. They are two different things.