Audio Research REF2 MK 1 Vs. MK 2

The REF 2 MK II has 6) 6H30's, 1) 6L6, and 1) 5AR4. The only reason for a "tubey" sounding REF 2 MK I is "tubey"(microphonic) tubes. If the tubes are rolled for accurate/transparent, NOS 6922's, the sound will be also. Siemens and Telefunken CCa's will both provide a clean, accurate, non-tubey presentation. As with any pre-amp, mic or phono stage: Tubes MUST be screened for noise before purchased. The CCa's were a specially selected, low-noise 6922 variant, but that doesn't guarantee all will be quiet enough for your pre-amp. A less expensive, but still excellent option, is the Siemens E188CC. I had them in a couple ARC pieces I owned(very extended, lucid and transparent). I'm using 6) Siemens CCa's in my VK-D5 now, and love 'em.

I also have the Ref2 MK1 modified by GNSC. I am using Upscale Audio's EH 6992s which are a improvement over the stock ARC 6922s. I've never had the MKII in my system but do know another person that tried the MKII but preferred his MKI. However as Hjp states it also probably depends on one's personal preferences; at least to some extent.

Anyone have a schematic for the Reference 2 Mk1 please?

Try www.arcdb.ws. It has a wealth of information including pictures and schematics. The MKI has 11 tubes, for example, vs. 8 in the MKII