ARC Ref 3: Tung-Sol 6550 in power supply?

Dev, yes I know. . . but I can only trust my ears, regardless of what the manual says. And in my Ref 3 the SED 6550C in the power supply declines even faster: 900 hrs may be the extent before the sound becomes dull and uninvolving with significant loss of dynamics and treble information. Please note that I am always specifying 'my' Ref 3, rather than to the Ref 3 model in general. . . it is entirely possible that the relatively rapid tube decline that I have observed is a phenomenon peculiar to my own unit.

Guido, thanks for the info. and I fully agree regarding manuals and respect any persons own findings. Allot of ARC owners recommend just as Oneobgyn above has mentioned to stick with the Audio Research tubes but obviously you have chosen to go another route what are your findings.

So regarding the tubes when do you start replacing them and which ones and at what intervals, it seems to me that you refer to your power supply going the quickest.

DEV, I agree with OneObgyn on the 6550 in power supply: the SED seems overall to be a more appropriate choice for me; I was able to compare new tubes directly. EH6h30PI Gold and the Sovtec 6H30PI apparently come from the same plant. According to the TUBESTORE they are not distinguishable electrically; I have compared a depleted Sovtec set with a new EH set, so I cannot say which I like better. Now on tube aging. . . in my opinion the SED6550C in PS is due for replacement after 800 to 900 hrs. The Sovtec 6H30PIs seem to start to decline at 1800 hrs of operation.

I hate to be repetitive but IMO there is absolutely no reason to use any other than the ARC recommended tubes

Thanks, time to get some new tubes and hear the difference. What's the difference between the tubes that are being sold by Gon members in the ARC section which are half the price and buying directly from ARC and paying at least 100% more.