M125 with Acoustats

I searched the forum and found nothing. So, I will ask my question.

Has anyone used the M125 monoblocks with Acoustat electrostatic speakers?

Thanks

Accoustat electrostatic speakers are self-powered, no amp required.

Certain early Acoustat models (e.g. X, Monitor) included direct drive tube amps. The later models (2, 2M, 2MH, 3, 4, 1, 1+1, 2+2, 6, 8, 1100, 2200, etc.) were equipped with a more conventional dc supply and transformer interface (Mk-121, Mk-131, etc.). These models require external amplification.

FYI: I got my good results (a while back) with BIG solid state amplifiers from SUMO and G.A.S.

j beede wrote:Certain early Acoustat models (e.g. X, Monitor) included direct drive tube amps. The later models (2, 2M, 2MH, 3, 4, 1, 1+1, 2+2, 6, 8, 1100, 2200, etc.) were equipped with a more conventional dc supply and transformer interface (Mk-121, Mk-131, etc.). These models require external amplification.

FYI: I got my good results (a while back) with BIG solid state amplifiers from SUMO and G.A.S.

Funny! Not denying what you state, but my brother keeps a pair of Spectra 11s. He drives it from a 7V output pre-amp, just fine. No power amp at all. Big box hanging off the back of the beasts, each with a 3-prong plug. But no outboard amp. Was self-powered an option, perhaps?

I have 2 sets of the X servo amps that were built exclusively for Acoustats (of course).  No amp is needed for them.  
I have a set of Acoustat monitor 3's that plug in just like your brother's BUT they do require amplification.  That big box off the back is just an interface for the speaker itself.  I have a Hafler 9505 amp that drives my slimlines.  

I just searched for SUMO and GAS  I had never heard of them.  Powerful solid state amps.
I was considering the M125 for these speakers because of wanting to keep the tube sound and as an option.
These speakers require a lot of power.

I have been running Acoustat for over 30years......if the bias is right ..most now are not..5k on the ESL panels my 50 year old stock Dynaco MK3 with the stock GE 6550s  you can drive the 2+2 an M4 to full output..
Yes my first pr in the 1980 were the Xs with the tube servo DD amps....but with the MK 121-a interfaces... they can be driven with full output...an play loud....with Any 50-60 tube watts.....
IF..if the bias is right...after all any ESL output is set by the panels bias...an like the Quad,Sound lab an Aoustats.... there bias is on all the time 24/7...so after 20-30 years the bias can get a little tired...hehe ...
Less than $50 in diodes an caps....like new speakers
I have ML CLSs, Sound lab M1, Quad 57-63s....but with the bias up the Acoustat play loud with deep bass...with 60 tubes watts..i have halfer mosfet amp also..that work well
Only other panels that can get close.. are my Magnepans....well to my ears...
So I say...long live Acoustat....
AcoustatAnswerMan Andy Szabo ...not me... is on the Diyaudio site... with lots of info....he work at Acoustat...

just google Acoustat Mk 121-2 interfaces pic....an you see the bias setp...re-work it.....for great sound..an the Acoustat DD tube amps





thanks for the site Bob.....happy new year to all

Thank you Bob and zx.

I think it would be interesting that when individuals pair speakers and amplifiers to also give both listening room parameters and sound-stage parameters. To define this a bit further, the room parameters should include:

a) Dimensions & type. Is this a multi-purpose room or a dedicated listening room.
b) Finishes and furnishings.
c) Speaker positioning.
d) Any other information deemed useful.

Sound-stage parameters should include:

a) Whether this is a 'sweet-spot' set up, or a wide-stage set-up.
b) Approximate distance from the speakers.

I think that this would allow the curious to judge whether the pairings are a fair representation of their own situations, or could be made so. I think that blanket statements such as "XXX amplifier will drive YYY speakers" need to be further qualified by some limiting parameters.

Now, writing entirely for myself, I keep a pair of older Maggies (true-ribbon tweeters, outboard crossovers) in a room that is quite large (17' x 28' x 10' - three french doors, lots of glass, plaster and hardwood, brick fireplace - soft furnishings and small area rugs) It is 'officially' designated as the Library as two walls have built-in shelving. But it is also the family room, main listening room and TV room when watched. The Maggies are placed on a short wall, asymmetrically, about 2' off the wall, facing straight out. I have tried tube amps (Dynaco & Scott) up to 75 wpc/rms. And solid-state amps from 60 to 200 amps. ONLY the 200 watt amp can drive *those* speakers in *that* room with enough headroom to make a reasonable volume over a fairly broad sound stage. Were I to cant the speakers inward and move closer to them, I am sure I could get within the range of a tube amp. Otherwise, not.

I keep a pair of AR3a speakers in a room that is 17 x 12 x 10, two french doors, lots of glass, finishes and furnishing as above. Speakers are asymmetric on the long wall for a very broad sound-stage. My 60wpc AR Receiver as well as the 75-watt Scott do just fine under those conditions. The 70 does not.

In all my other listening venues which are much smaller and have mere 9' ceilings or lower, into various AR speakers from Athenas to M5s, about any of my amps are OK. The Dynaco ST35, however, likes the Athenas, none of the others unless I keep the volume quite low.

My brother keeps his Accustats in a very irregularly shaped room that overall is about 15 x 12 x 9, carpeted and softly furnished. Nor does he listen at anywhere near realistic volumes but typically at more-or-less background levels.

Horses for courses.

Peter W. is spot-on in his assessment of the parameters that need to be taken into account when deciding amp/speaker compatibility. All the details he mentions are why, when a speaker manufacturer gives "watt ratings" to his devices, the range is often quite large. And usually almost meaningless except as a common-sense guide.
The way speakers interact with a room is complex and not easily quantified. Our own audiobill has a succinct aphorism which handily expresses this: "The room and the speakers is one unit". Meaning that the whole room is in effect the true speaker enclosure. Which necessitates the assessment parameters of Peter W. being part of the process.
Add to this list the need to take into consideration what sort of music, how loud, and for what purpose. Not to mention your OCD Level and your partner's level of patience.