2. amps-preamps
  3. 1397501648

Preamp for Aesthetix / Atma-sphere

Hi

I have the Aesthetix Io Eclipse with volume and dual power supplies, Atma-sphere MA-1 monoblocs (140 watts) and Audiokinesis Dream Maker (93 db sensitive) speakers. These are great components. My question is about system synergy, how to make them play together.

I have been running the Io direct to my amps since I first bought the Mk2 version back in 2004. At the time, I had a Krell FPB600, and in that context, it was a blessing, and a great step up from the Krell KAV 250p preamp. I'll never forget my first impression with the Io - it was like going from the wooded hills up into the mountains. There was no going back.

With volume, the Io functions as a preamp. It looks like a preamp. Someone here on A-gon said going direct is best - which I interpreted as: it IS a preamp! So I thought, OK I have a combined phono and preamp - problem fixed. But it wasn't.

From recent testing I have finally become convinced that the Io does benefit from a separarate preamp. Even if clarity and detail is better going direct from the Io to the amps, the punch and "here-ness" of the music is clearly better with a preamp in the chain, at least in my system.

Trouble is, which preamp? I am testing a small solid state Musical Innovation preamp, which helps with the punch but veils the music. An optimal solution might be the Aesthetix Callisto, preferably with dual power - but I don't have the space, and I already have a lot of tubes and tube heat. I have space for one or possibly two boxes.

From what I have heard so far, a solid state might do the job well (in my tube-rich context), however it should not impart any s-state artifacts or reduce the resolution from the Io Eclipse.

The ideal would be to test a few tube and s-state preamps, and then decide. However, this is difficult where I live, so advice is welcome.

My question relates to my own setup of course, but is relevant for everyone with a top phono stage on the one hand and amps on the other. What is best in the middle?

From recent testing I have learned that problems that I thought were related to the speakers, the phono pre, the pickup and so on, were in fact related to the preamp issue. For example, the Dream Makers straight from the Io may sound a bit lazy and washed out in the bass, very clear in mid and treble but not fully embodied. Plugging in the solid state pre, the situation becomes dramatically different, now the speakers are driving, propulsive. Very enjoyable, but some detail is lost and some transistor things added that I don't want.

So I am looking for a solution with most of the plusses, and not much of the minuses. The preamp must be fully balanced with XLR in / out.
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o_holter OP
977 posts
 
I did some more listening with the Einstein at low-moderate levels (since the family protested last night). It doesn't evoke the grand passions of the higher level but it still sounds very good.
I wonder, would it sound even better if I turned the amp gain a bit down. If I remember right, it is possible to do this in the MA-1, simply by taking out a pair of output tubes.
albertporter's avatar
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albertporter
4,949 posts
 
Thanks, Albert, for interesting advice, which I will follow. You probably mean the one 12AU7 tube (only one in The Tube mk2). Do you remember the type of 5814 CBS Hytron?

I thought I remembered there were two in the Einstein but perhaps I remember wrong. I looked for nearly an hour today to find that tube, I know it's around here somewhere.

I know the box was military type, brown cardboard and very old. Perhaps 1940s (or 1950s at latest).

Audiolabyrinth
@ Albertporter, Hi, Will the 5814 CBS Hytron tube go in the place of any 12AU7 tube socket that is used in other name brands of components, never heard of this tube, where is it made, and by who, what is the projected life span, where do you get them from, Is there a specific year that is very good?

Audiolabyrinth, this tube will work where 12AU7 is called for. I checked the Sams tube manual and it's electrically fully compatible.

CBS Hytron is an old USA brand, found at specialty tube dealers and Ebay. Life span is determined by the circuit it's placed in, some equipment is easy on tubes and some are brutal, making for short life.

The tube is extremely high quality as are most USA and Euro tubes from 40s and 50s.
nkj
130 posts
 
Interesting,

I have the Io with 2 supplies and Volume controls. I have never been wanting for dynamics. The whole system interface & efficeincy considered + room = jump or dynamics. I am not talking about sound pressure.

I run electrostats mostly but I am familiar with the big dynaudio C1, Revel , Wilson and Avalon etc. You don't miss want you don't have but my exposure to these other systems tells me I am ok.. with Beveridges it is actually startling on dynamic contrasts... again I am not talking SPL.

I can't argue with the quality of your equipment. It is surprising .

With its warts, the Io is still probably one of the best phono stages I have heard ( Klyne, ASR, Zanden + more) so I would have tried for an Atma or Callisto to trial if at all possible and see where you land.. It is an interesting and expensive with variable outcome in terms of the journey.

Good Luck
acresverde
396 posts
 
You would need to remove a specific driver tube from each amp (don't know which one) and replace each with a special shorting tube socket that Ralph sells. Gain on my M60s is reduced by 12 db (supposedly)using this tactic.
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o_holter OP
977 posts
 
I have ordered a pair of Siemens Halske 6922 gold pins from the 1960s for the phono input + 1 Telefunken 12AU7, from Brent Jessee. Quite expensive but I know he delivers quality (last year I bought Telefunken 12ax7s for the Io from BJ, working great, very low noise). Also, based on Albert Porter's advice, I have ordered a Hytron from ebay seller Greengirl613: "Vintage CBS Hytron 5814 A Black Plates D-Getter Stereo Tube 1959". It may not be the exact same, but seems close. Will be interesting to try the Tele vs the Hytron.
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