Audio Research Reference 150 severe distortion


My Reference 150 is emitting severe distortion in both channels. I checked the bias of the K120 tubes and one tube in both channels is reading as low as 20, rather the the standard 65 range.

Does anyone know of a possible fix that will not involve me shipping the amp back to Audio Research?

Both bad tubes are less than 3 months old.

I gotta play my Liberace Christmas music!
128x128shaq
Shaq ...could be bad tubes; could be blown bias resisters. Switch "good" tubes into the sockets that read 20 mV. If the bias stays at 20 mV, that's a good sign there's a blown bias resister. If the bias can be adjusted to 65 mV and the problem moves with the tube, it's the tube.

I find it odd that both channels present the same problem. Try the diagnostic technique I suggested and report back. Do you have any spare KT-120s. If so, you might need them.

Hopefully, the problem is just a bad tube or blown bias resister. If a blown bias resister, I would ask Kal (ARC service rep) if there's an authorized repair center near you. I would avoid shipping the amp for a simple bias resister repair if at all possible.

Rather than me whining on, try what I suggested and report back.
It looks like AudioReseach Ref series are similar to Ferrari that have great performance but for the price of poor reliability.