Responses from gmuffley

Question about replacing 12AU7 tubes.
I disagree with Bigshutterbug. I have large stock of 12AU7s; new and vintage. Telefunken are my favorite vintage tubes. Among new tubes the EH 12AU7s are very nice, but the Psvane 12AU7s are fantastic. I'm starting to lean more toward Psvane even ... 
CD player closest to vinyl?
The latest Audio Note Dacs. 
Has LED caught up to Plasma?
The new Sharp LEDs are stupid good. 
Impedance Mismatch: A.I. M3A, Krell KSA100
Romandoc is correct. The value of the output coupling cap in tube preamps can significantly increase the output impedance of a tube preamp in the bass frequencies as compared to the rated output impedance at 1 KHZ. The actual output impedance of t... 
Graham Phantom I tonearm
The gauge is your problem. 
Should I try to improve speakers at $2000.00 range
This thread demonstrates one of my pet peeves. I should say at the outset, that I am not singling out Johnnyr or Dayglow. But, I have to ask Dayglow has he ever owned a pair of Sl-700s? Has Johnnyr heard a pair of Sl-700s since "back in the day"? ... 
Should I try to improve speakers at $2000.00 range
The SL-700s are still hard to beat. The crossover components can be updated but the fact remains that the aerolam enclosure is still state of the art and the drivers are very high quality. 
AES Superamp or Quicksilver Mini-Mites?
I have owned both and prefer the Quicksilvers. 
XLR to RCA Adapters
There is NO inherent superiority of balanced vs. single ended designs. Balanced cables are superior for very long cable runs typical of sound reinforcement applications. For consumer gear, either can deliver the same results. 
To add to Rrog's excellent post, the Quicksilver 8417 amps can be easily converted to use 6550/KT-88/El-34 tubes. 
Quicksilver has several models that you can pick up for less than $1K used. 
Budget Tube Preamp with Remote
Used Quicksilver line stage with remote. 
Anyone have experiance with KLH-9 power supplies?
The usual suspect in the power supply is a failed diode in the voltage multiplier circuit. It IS a pain to melt out the wax in the PS. I did it several times. 
What's the best Tube DAC you have heard?
Used ARC DAC-3 MKII or Audio Note zero oversampling units are hard to beat for the price. 
Audio Research Classic 60 & 120 owners
Sounds normal to me for those amps.