Atmasphere mp1 mk3.3 with phono

@phantom_av
I have an MP-1 with all upgrades except Caddock resistors, which tubes are you running not NOS? Just out of curiosity?

Thank you, I know Ralph doesn't recommend NOS for the 12AT7 phono sections and he uses Shuguang as the stock tube which BTW is excellent.Fort the preamp he supplies Shuguang brown base which are good, I have NOS Sylvanias 6SN7GTBs on mine and found it to be an apparent improvement. I mixed the stock tubes with 2x CV181-Z, Shuguang Black Treasures and did not like the results, on my previous MP-3 these same tubes were very good but the MP-3 needs only 2 and the MP-1 6 of these.

NOS 12AT7s that are quiet enough to work in a phono section capable of working with LOMC cartridges disappeared long ago. I'm not saying you can't find some, but they are very hard to find these days 

For the record, on the 12AT7's comment Ralph, I have Raytheons and Westinghouse NOS, Shuguang's the Z version new production. After measuring these tubes on my B&K 707 tube tester the "readings" are not comparable to your stock Shuguang's, the ones you supplied with your amp are 120 on the tester scale, the NOS I have are usually at 40-50 and the Shuguang's Z version (new production) are on the 90's
So yeah I second your comment that finding a good 12AT7 older production would be challenging and even the new production chinese tubes won't measure "as well" as your stock ones.Someone people needs to understand, when China (Shuguang, PSVane) produces tubes their QC separates these tubes and distribute and prices these accordingly so even new the same tube you will find it for a very wide price range, "on average basis" the more expensive tubes will be better, my point is I am positive your source for your stock tubes must not be "cheap" (hence the high readings) and the product is better than purchasing directly from China from other sources. And this comment applies also I think to the Caddock resistors you use, like you mentioned special order.