ARC PH7 Owners is it worth updating to new 5881


ARC PH7 Owners is it worth sending my unit back to ARC for the 5881 tube update? If so, what are the differences in sound or reliablity?
etbaby
There is a "upgraded" Ph7 for sale now on Audiogon,by a dealer who also describes the difference with the single 5881 tube.
ARC has reputaion for outstanding products and I doubt it would put out an upgrade that was worthless.
I will send my PH7 in for the upgrade early March, I will be on a short vacation and I won`t miss while I am gone.
Len W
I had severe problems with the original power regulation scheme of the PH7 which uses three 6H30 valves. Faint noise that varied in frequency was audible while playing music. Roger Hug put it on the bench and the oscilloscope showed a very strange waveform at the preamp output at around 430 kHz. With the cover removed it could be seen that one of the 6H30 was burning much more brightly. I bought three more 6H30 and Roger installed them. It might have been nice to be able to test the new tubes but try to find a tester that accommodates the oddball 6H30. Again one of the tubes would run away. It is my opinion that the PH7 suffered from a flawed power regulation design, and the offer of a 5881 circuit from ARC was not so much an upgrade as it was a bug fix. I called Leonard at ARC to express this view. His reply to the assertion that the PH7 had a design flaw was to tell me the “upgrade” cost $250 plus shipping. So I had the 5881 circuit installed and the PH7 is well behaved now.
" I called Leonard at ARC to express this view. His reply to the assertion that the PH7 had a design flaw was to tell me the “upgrade” cost $250 plus shipping."

I thought Leonard retired a year or two ago?
I own an ARC PH-7 w/ 5881 upgrade. Not a hint of trouble. It sounds great.