Setting bias on a vintage ARC

Check the ARC website here: www DOT audioresearch.com/download/

Type V35 in the search bar and it will take you to a download with instructions on how to bias your amp.

I checked the ARCDB.com website and noted that your amp is 28 years old.  May I suggest that you call ARC and speak to Greg.  He may have some useful tips about the biasing procedure.  In addition, you may want to ask Greg if you should send your V35 to an ARC service center or the factory for a checkup.  Some of the caps and other passives may need a refresh. 

BTW, biasing some of the older ARC amps is really tricky.  Don't know anything about the V35.  That is why I suggest you call ARC.

Good luck.

BIF     

Have you tried calling ARC's service department?

BillWojo

Not yet on calling ARC. I’ve check the bias on my CLASSIC 60 but it didn’t require adjustment. 

I did download the manual and checked the bias adjustment procedure, but it’s not clear other than to say to set an “average” bias of 37.5 and the numbers between sides can differ up to 10%. 

OP, ... call ARC.  I would not be surprised to learn that a 10% variation is not critical.

I own an ARC Ref 150 SE amp.  There is one bias pot for each matched pair of 2 KT-150 tubes.  The set tube bias is set at 65 mV and the slave can be between 57 and 73 mV.  So, +/- 8 mV is spec.  As a practical matter, I try to match my tubes within 2 or 3 mV. 

I have no idea what the spec is for the V35.

BIF 

You need to use matched pairs of tubes. Let the amp warm up and run idle for about 15 minutes or so. The amp needs to be at operating temperature with no signal. I always check bias after listening. Mute the preamp and wait a few minutes. The manual says to set the bias at 75ma per pair. ARC likes to run tubes hot. I would set the bias a little low, maybe 72ma. I ran my 6550 tubes at 62. It does not hurt to run the bias a little low as long as it doesn’t affect the sound.

I would call ARC with the serial number of the amp and see if it has ever been serviced. If the large caps are original, they need to be replaced. If the caps leak, they can damage the circuit board. It doesn’t not hurt to let ARC go through the amp and bring it to spec.

I’ve ordered new large caps. I will change these. I did this for my Classic 60. Really easy. Visually the other caps look ok, but that’s no guarantee I know. 
I intend to call ARC today.