Originally Posted by
Antinchip
I got my 7R's from Glenn via Adrian at Audioflair in late 2016. They came with;
RCA 12BH7A stamped "USA"
Mullard 85A2
JJ ECC83S
The distilled discussion as to valve rolling with Adrian and his recommended valve supplier, Matt Francesco, was;
For the 12BH7A, alternatives might be Tungsol grey or black plates having more "grip" but the RCA's with more "presence". Another comment; "The 7R's being very grippy anyway I can see why some go for the RCA". Otherwise GE with a "dryer, cleaner" sound. I didn't audition the alternatives and stuck with the RCA's.
For the 85A2, Mullard was deemed "best" so I stuck with that.
For the ECC83S, NOS Mullard ECC83 were recommended for a "more noticeable uplift". I auditioned these and they stayed put.
I have been very much enjoying the 7R's, now with a more recently acquired Micro 25R (2 x Electro-Harmonix 12AX7, 3 X JJECC83S, Mullard 85A2), all revealing music with great presence, life, detail and transparency whilst not dry or clinical. I have an RIAA-R, which seems to offer great opportunity for valve rolling. Can't quite remember the original valve compliment but it is now;
Tungsol 12BH7A grey plate
2 x Tesla E83CC
2 X Mullard ECC83
Mullard 85A2
Since I have the RIAA-R my next step is to get Glenn to remove the phono stage from the 25R and upgrade to the 25RSLS linestage (perhaps with some other mod's). I will probably start with Glenn's USA RCA12BH7A's and see how it goes from there. Should hopefully be done in August.
Have fun.