Audio Research REF2 MK 1 Vs. MK 2

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

Anyone have a schematic for the Reference 2 Mk1 please?

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.

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.

Dave, I thought there were 6 6H30 tubes in the REF2MkII.

05-01-08: Hjp
The Mk I has an all vacuum tube audio circuit. The Mk II has an all solid state audio circuit (not just the input stage....all)

This is not correct. The input stage uses J-FETs followed by 6H30 tube for the 2nd gain stage and another 6H30 as a follower/output driver. That's why there are four 6H30 tubes (two per channel).

The Mk I has an all vacuum tube audio circuit. The Mk II has an all solid state audio circuit (not just the input stage....all) with only a single cathode follower at the output. The Mk I has all the best sonic qualities of tubes while the Mk II sounds more like a solid state unit, albeit a very good one. Take your pick based on your personal preferences. I vote for the MK I. To me, its sounds more like what I hear in life.

I've had a Ref 2 mk1 for several years and love it. Because of the input/output stages are all tubes, (along with the 6922's) the sound is very "tubey". Lots of bloom. Mk2 uses a different tube set and jFets on the input stage. Sounds more crisp and clean than the mk1, but with less bloom.

That is the beauty of the MKI in that you can "play" with all type of tubes you describe whereas with the MKII you are pretty much stuck with the 6H30.
I have a REF 2 MKI modified by GNSC with Amperex 7308 PQ white label and RCA 6L6GC blackplate and Philips Miniwatt steel base 5AR4 in the power supply.
Dead quiet. I strongly recommend those tubes with the MKI. Very little experience with the Funken's.