2. amps-preamps
  3. 190750-149162

ARC Ref75se bias

So I have a ARC Ref75se, with tubes under 300 hrs, and a new Puritan 156, with maybe 30 hrs. I checked my tube bias not long before getting the Puritan. For some reason I decided to check it after the Puritan was installed, with my amp plugged into the Puritan. I found it odd the bias on all four tubes was on the low end. Not in but close to the "bias zone" on the meters. I know I could plug the amp back in to the wall and see what the bias does. It always remained very stable on all four tubes. Any ideas? 

128x128skids
ghdprentice
6,789 posts
 

@audphile1 

 

+1

peter_s
1,325 posts
 

Really?  It’s limiting current even on idle? I don’t know the amp.  Maybe it runs hot. But I’m  surprised at that.  Yes, plug it back into the wall and report back. 

skids's avatar
skids OP
69 posts
 

I will plug it back into the wall and see. I do let the amp sit for a half hour with no signal running through it, before checking bias,as per ARC's recommendation.

audphile1's avatar
audphile1
4,759 posts
 

@peter_s about your question…if you look at the specs of the amplifier…it idles at 230 watts.

I owned PSM 156 and I in my opinion it’s extremely overrated and overhyped. It does seem to lower the noise floor slightly but at the expense of reducing dynamics not only with amps but also with source components.

skids's avatar
skids OP
69 posts
 

Just an update, it does appear keeping the amp out of the Puritan does keep the bias happy. I will continue to check it for a little while yet, and continue to get some burnin time on the Puritan.

@audphile1 Can I assume your Puritan had enough time on it to fully burn in? So the 156 was  not a good choice for your system. I imagine it can be a system synergy thing like a lot of things.

 

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