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

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. 

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.

@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.

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.

 

@skids yes I bought the puritan new and had it for over a year. So enough hours on it. 

Break in won’t address the current delivery. What you observed is what the puritan does. System synergy is definitely critical but if you have a power conditioner that chokes the components power supply, synergy doesn’t come into play. It’s like breathing thru a straw. 
 

All you really need is a dedicated line, preferably two so you can separate digital and analog, and use top notch components and power cables. If you really still need power conditioning then, a passive unit like the Shunyata (even the older Hydra) should do the trick. Or if you can’t run the dedicated line still try passive conditioner. The objective is to not do harm. The effect of power conditioners is not jaw dropping if you have components with properly designed power supplies.