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Preamp Experiences with Atma-sphere Amps

I have finally swapped my CATJL2s for Atma-sphere M-60s and with my Merlin VSM-MXEs they are a revelation. Both are world class amplifiers, but I now beleive that IF you speakers are OTL friendly, it is hard to beat OTLs for speed, clarity, transparency, etc. In other words, I love them with the Merlins.

I would like to hear from those that have experimented with preamps that match well with the Atma amps, including the Atma pres versus others, and passive pre experiences if you have tried it. Right now I'm using a Joule LA-150 MKII that is single-ended and sounds fantastic and quiet so I'm not sure that simply running quieter with balanced outs is a goal, but I'm open. I'm single sourced with Accustic Arts transport and DAC with at least 2V output (might be higher)but it does seem the Atmas need some gain to drive them with their highes input sensitivity. Thanks in advance for your collective wisdom and experiences.
pubul57
clio09
3,355 posts
 
Oh just go ahead and get some Joule OTLs and go head to head with the Atma OTLs. That should be some fun.
pubul57 OP
3,712 posts
 
Indeed, and I could get rid of my furnace in the winter time. Tony, I somehow suspect that I may very well have to try the faceoff someday.
pubul57 OP
3,712 posts
 
What 6sn7s have you been succesful with in the MP-1. I'm using Early Sylvania 6sn7 gtb and they sound very good to me and quiet as far as I can tell. I'm using RCA Clear Tops for the 12au7 position (no phone stage).
emailists
923 posts
 
Tim,

What position did you put the NOS tube in the MP-1 line stage?

Are you saying you only need to replace 1 tube on each channel?

Have you tried replacing all?
jtimothya
612 posts
 
Here is some of what I've learned about tubes in the MP-1 Mark III:

As you stand facing the MP-1 with its cover off, the 6SN7 tube closest to the front panel in each channel has the most sonic influence on the linestage.

The three 12AT7s aligned in a row toward the left rear of each channel have the most influence on phono stage sonics.

The pair of 6SN7s in each channel that line up behind the tube closest to the front panel are particularly sensitive to noise and unmatched sections. As the MP-1 is a fully balanced design, closely matched sections *within* a tube are v. important for all its tubes.

Tube dampers really help on tubes you want to insure are the quietest. 'Herbies' are easily the best I've tried. In each channel I use 3 in the line stage and 3 in the phono section. At first you may think you've lost some sparkle, but give 'em time and you may find as I did that you've lost some distortion and gained a bit more timbral rightness and quiet.

With 10 6SN7s in the MP-1 and 5 in each channel of the MA-1s, I would have few spares if I used 20 tubes from my NOS stock to fill every socket. In my opinion the 6SN7s in the amps have more influence than all but the one in the MP-1 that I identified above, so I replace all in the MA-1s, and just the one in each channel of the MP-1. Today I'm using '40's black glass Ken-Rad VT-231s in the MP-1.

I appreciate Ralph's comments about the difficulty of finding decent 12AT7s for the phono stage, however it can be done. There I'm using late '60's Siemens-Halske triple mica E81CC tubes in the three critical spots with a Brimar filling out the fourth. I've also had good luck with the Sylvania Gold Brand 6201 sold by Kevin Deal, but the Siemens are really special.

YMMV.

Tim
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