Problem with AR Ref 300 Mk II - any experience?


One of my Audio Research Ref 300 Mk II Power Amps has no output. Power ist ok, Switch on process is as usual, but the 8 power valves show practically no voltage when checked. The meter moves only some 3mm from the "parking position" on the left side.
Does anyone have any similar experience?
Are there any switches, additional fuses or the like, which I am not aware of?
Best regards!
Otto
ozatschek
If you are on the West Coast, Gary (Hifigeek1) is an authorized ARC service tech and can he you. You can e mail him through the A'gon system. If not, call ARC and ask for Kal. He can put you in contact with a local ARC authorized service center, be it in the CONUS or elsewhere.

I'm not electronics savvy, so take with this with a half a grain of salt. But if all the power tubes are subject to the same problem, it sounds like a common power supply issue.

Good luck
Ozatschek, 2 quick follow-up points. One -- each amp weighs 132 pounds. I would try and find someone who does house calls. No joke. There's an ARC authorized service tech who lives near my house and makes house calls. He was over about 2 or 3 weeks ago to fix an open bias resister. The fix took all of 30 minutes.

Two - here's something else you can take with a grain of salt since I'm not a tech. I read the ARCDB web site description of the Ref 300. I see that it has a bunch of regulator tubes in the power supply. Wild arsed guess here .. but did you check all of the tubes, particularly the PS regulators for life? Just asking. If a blown PS tube controls the output power tubes, it might affect all of the output tubes, which is your situation.

Incidentally, regardless of how you make out, I would still contact ARC to see if the tech folks have any preventative maintenance suggestions such as replacing tubes, caps, etc. Your amp is not ready to be retired, but it ain't no spring chicken either.

Good luck and let us know how you make out.

BIF