Responses from hifigeek1

New KT150 tubes?
At this point I do not recommend using the SED6550 (winged C).Before production stopped, (the factory burned down supposedly), these tubes became very problematic. I only use the 6550we at this point. 
Luxman SQ-30u noise
You may have a dirty or intermittent tube socket on the noisy channel. 
New KT150 tubes?
Amen to that! 
Anyone talked to Dean from PSE?
I had been out ill... 
regulator in AR D70
You can read the zener diode numbers and look up what their voltage should be. Better yet, I would suggest getting your amp to an ARC warranty repair place before you possibly rip the through hole plated traces up and then it's not worth repairing. 
regulator in AR D70
I thought I gave you all the voltages you needed to check to make sure the regulator was working properly and why post this here? 
Phase Linear 700 & 400 series II
Never owned one. Had to work on them though. 
Phase Linear 700 & 400 series II
Ya...they blowed up real good! 
McIntosh to be on How It's Made this Thursday
Thanks for the heads up on that. Would have been nice to have the whole show dedicated to the Mac tour. I still don't understand the l.e.d.'s under the small signal tubes. I guess I'm old school. 
Phase Linear 700 & 400 series II
They tend to like to blow up.... 
When to recap?
A ploy for income purposes??? That is baloney. It is true that many Mac solid state amps have G.E. computer grade electrolytics in the main power supply that can last quite a long time. The axial tubular caps in your Mac should be replaced. The ru... 
Audio Research Corporation ARC Reference 600
Let me also add that since you have speakers that have a 102dB sensitivity @ 1W 1 meter, noise becomes more of an issue. The Ref75 should be quiet enough, but what kind of preamp are you using? The s/n ratio of some tube preamps would be low enoug... 
upgraded fuse holder
I'm assuming the .5A fuse is for the screen supply of the tube amp in which case I might use a ceramic fuse vs. a glass fuse as glass fuses can shatter. Any properly rated fuse holder i.e. from Littlefuse etc. should work fine unless the amp uses ... 
Audio Research Corporation ARC Reference 600
Although I am an ARC warranty repair station and would be happy to service them for you, the fact is with a total of 32 6550 output tubes and 8 regulator 6550's you have multiplied your chances of arcing a tube by a large percentage. Unless you ne... 
Audio Research D70 mark1 + schematic
I've never seen a bias pot fail in a D70 or D115. They can get noisy however. It's 65mV as you are measuring across the resistor.