Best amplifier for Acoustat 2+2 electrostats for holographic sound, or change speakers?

The cost of the Acoustat 2+2 upgrade in 2013 was $550 including return freight (outbound freight is on you).  Meets your budget criteria, if they have not already been brought up-to-date.

I may be asking the obvious, but if your Acoustats are not up-to-date in terms of available upgrades, they may not be operating at their peak potential.  I had my 2+2's upgraded by Roy Esposito (formerly of Acoustat) back in 2013.  Completely rewired the interfaces with mono-crystalline wire and replaced nearly all the other components, save the medallion transformers.  Also opted for the "Air" upgrade, which provides a manual switch to by-pass the high frequency adjustment pot.  I use a Mark Levinson ML11/ML12 amp/preamp combo to drive mine; totally coherent, detailed and transparent.

I have heard Microphonic and I have heard the measures put in place to control the audible effect.

When controls are in place, there has been nothing present for any length of time to cause any concern.

The Pre' has made such an Impression on myself used as loaned models in my system, I have purchased Bespoke PCB's with a option to have oversized components added, there is plenty of real estate.

There is also Bespoke Built VC's to be used with the Monoblock Balanced Pre' I am having Built.

The Casing is to be Airtight P'holz and the Nutube will, as an additional measure  be embedded into its own P'holz Sarcophagus.

A selection of the local HiFi Group, as result of the Nutube DHT experience, are now experimenting with Tube DHT Pre Amp's. Speakers being used are Active Cabinet, Passive Cabinet, Horn Loaded Cabinet and ESL. 

I was given my first experience on Wednesday morning in a very well known system, where the CD Source > Valve DHT (gain matched) to a Neurochrome Power Amp > Passive Cabinet Speakers .

This was the best I have heard this system being driven by SS Power Amplification.

There is also a Design coming together to modify the Valve DHT, something about the methodology for heating/driving the Tubes. 

My visit to this home prior to this visit was listening to the System via a Heavily Modded SP10 (Bespoke Speed Control / Platter Bearing Overhaul) > Bespoke Built TA > Newly Refurbished AN IO > Heavily Modified design for a KB1 (Three Box with - Blackgate Cap's - Bespoke VC)  > 300B Power Amp's.

Hearing this set up in use was also an indelible experience. The new encounter with Valve DHT and SS has been quite different as an impression made, but both are equally indelible.

The time will come when everything is modded to its end point, and the side by side comparisons will commence. 

Note: When the EE goes down the path of modification, the Base Model is maintained and Modification Models are built from scratch, these are then easy to discern where the Plus/Minus points are discoverable.      

@tomic601 agreed those Korg tubes were microphonic in my experience with them B1 as well.

Another cool thing about the Orchard is they sell the proprietary modules. Amps can be assembled by connecting the modules to their power supplies. This saves money. After buying a different brand new amp, I joined the Orchard Audio tour. The Orchard was amazing and I bought an assembled one. If I'd had this amp sooner the Acoustats wouldn't have set in mothballs for twenty years.

Thanks,

aldnorab

Seems like the target has shifted a bit… i would still advise diffusion and not a bunch of absorbtion if tge new target is dynamics. Since it is a dipole, some experimentation always needed. Lack of dynamics on the low end normally means too far out in room. Obviously i have not heard the Orchard but it sounds like a very innovative demo offer. @clio09 wish i had a chance to hear RM’s direct drive… lots of juice…

@pindac How lucky…in my sample size of 4 all of those Korg tubes are microphonic…. it’s cool…. has intriguing potential…but…

As an alternative suggestion to having to buy into alternative Power Amplification.

I am very very familiar with the Nelson Pass Design Korg B1 Pre Amp.

If the gain of this Amp will work with the Power Amplification, for the money required to acquire the Basic Model, there is a lot on offer.

I have mainly heard it in use across a Variety of Power Amp's, both SS and Valve, but nearly always with ESL's.

I have also heard the Basic Design having undergone some of the now known upgrade tweaks, different Cap's, VC.

All build guises demo'd,  have delivered to what I class as my preferred description of Holographic in the earlier post.

As a trait, the Korg B1 will tighten up the lower frequencies, where a Bass Decay is with a defined edge and not lingering. Such a control of this frequency, enables the Mid's and Highs to be improved in their presence. The overall frequency range is much improved in coherence.  

The Envelope developing, is something that gets worked towards by improving interfaces in general throughout the audio system. The magic bullet to attain this, is perseverance and willingness to try out different interfaces, as time goes by things discoveries are made that are wanted to be maintained, where there is no want to return to what was before.      

Just hooked the Acoustat 3 Medallion to my Orchard Audio StarKrimson Stereo Ultra with dual power supplies. Absolutely amazing soundstaging and detail. Way out past the speaker edges. The 3's have never sounded so good. 500 watt per channel suits them well. I was going to buy new speakers, not now. 

Orchard Audio is running an amp tour with the V2 version. Listen a week for free, then pay to ship it to the next person on the list. Sign up on their website.

Thanks,

aldnorab 

+1 clio09

When I had my 2+2s originally had the interfaces. Eventually I got a pair of their servo amps which sounded way better, but back then 20+ years ago they were unstable. However, long after I sold them someone updates them and are said to be very stable HTH

Try stacking two Stillpoint Aperture panels dead center on the wall behind the Acoustat’s ( the first one approx 2 feet off the floor) and your sense of focus and immediacy will be noticeably enhanced... Also the resultant sound will be somewhat more lively, and engaging.... unfortunately they are somewhat pricey    (2k new).

Cheers.....

I would get rid of the interfaces on those speakers and use a direct drive amp. I have Acoustat Model 2s and did exactly that using the Acoustat Servo amps. Going with a direct drive amp removes the transformers from the equation which can restrict dynamics. If immediacy and dynamics are your goal as far as I'm concerned direct drive amps are your answer.

Thanks, all, for the thoughtful responses.  To answer pindac, I am looking for 1) more immediacy and a bit more dynamic response of the various instruments and if possible, pushing the soundstage more forward (didn't mention that before).  I realize that the source recording has a lot to do with what is reproduced and a bad recording isn't going to be transformed into a life changing audio experience by the system, no matter what the quality of the equipment is.

I currently have 2 sets of amps and line stag preamps, so I can sell one of the sets for maybe $3k for a purchase.  It seems, though, that the resale value is always lower than what I hope for.

I also am wondering if I should look at other speakers, particularly open baffle designs.  The drawbacks of diving back into the speaker arena to me are 1) selling the Acoustats because of their size and vintage, and 2) the gazillion choices that I can read about but not audition.

Also, like all planar these need vey precise positioning. 

This statement is not applicable to the big Soundlab speakers.  "Careful", yes, "precise", no. They can be near or far from the side walls.  They should be 2-3 feet from the back wall or corners or some bass peaks will occur in some rooms.  Slight relocation will reduce this dramatically with care.  But never never never, insert an "equalizer" between the pre and amp or you will lose much of the magic you worked so hard to achieve.  They can be 6-8 feet apart, 10+ feet apart, 10-14 feet from the listener, or as an incredible experience, the user can sit a couple feet in front.  There is no need for the listener to shift their head to find the "sweet spot".

Roger Sanders makes one version of his solid state amp specifically for ESL’s (the other for magnetic-planars---Magnepan and Eminent Technology).

@tomic601

+1 yes, I missed that. Often planar require much more reflection than dynamic speakers… it would be easy to have overly dampened the rear walls. Also, like all planar these need vey precise positioning. 

A million years ago (mid 90s) I had 2 + 2s. I used both the interface and eventually their servo amps, which are amazing, but back then they had red glowing tube issues that scared the pants of me. Someone does update them and is said to make them totally stable. Do a search and you'll be rewarded

Wow @pindac, what an outstanding response here!  Sadly it takes a lot of time, trial and error, patience, and even luck, to assemble a system to achieve the initial experiences of the attributes that you describe so well here.  Taking what we learned to get to that initial point of "success" with further refinements to the system takes us to (2) in your response.  The end result is that it is often difficult to end a listening session and return to reality.

John

A description of what Holographic Sound as term means to yourself would help as it is widely used to mean a variety of perceptions for a presentation of the end sound.

I have attached a few description given by others on their take on Holographic Sound.  

(1) "Holographic means that the music isn't rooted to the speakers, but instead seems to be originating from specific areas where the musicians and singers are arranged throughout the soundstage of your listening room -- especially between and outside your speakers -- in the best cases, there is air between them and you can imagine some closer to you and some further away -- the proverbial deep and wide soundstage. 

But, holographic means the musicians and singers appear throughout the soundstage almost like holograms."

(2) "My definition would simply be different words than those used above. I think "holographic" is more of a situation where the illusion becomes believable and almost touchable. Whether it is a soundstage (sonic holograph - nice term) or visual field (hologram), the specific event takes on an atmosphere of real volume and space."

(3) "I think 3-dimensional sound has more in common with multi-channel home theater set-ups, which can provide the most easily heard holographic situations. Surround sound would then be the engineered product of sounds delivered in specified areas. These sounds are what I enjoy as the novelty of special effects."

I myself use a Stacked Array of Electrostatic with 845 Monoblocks Power Amp's.

Upstream of these I have used a variety of Pre Amp's and brought in a large selection of Phonostages and even more SUT's, along with a Head Amp to make the most of the Vinyl Source.

For the Digital Source, I have been less adventurous, a Bespoke Built DAC using Valves in the Output Circuit along with a CDT, has offered a very good impression in the home system and performed exceptionally well alongside much more expensive Digital and Vinyl Sources when used in other systems.

When I get a better understanding of your description of Holographic Sound I will add more, as I have been able to create the perceptions that are a version of what is described above, and I believe beyond what is described above. Especially when it comes to the 'Envelope', there is a perception that can be generated in the listening space, especially a listening space that is seemingly expansive, voluminous.

In such a perception of Spaciousness, there is also another perception to be encountered, where the Imaging of a performer is perceived as being locatable in the space, when the perception of the performer has embodiment, there are other perceptions that are possible to encountered as follows.

The 'Envelope' is where the produced Notes and Vocal produced take on a perception of their being formed, the Note/Vocal has its own embodiment, as it seems the Imaging has further layers, where the performer is visualised creating the sound being produced. 

It is when the End Sound and Psychoacoustic Affect attains this level of perception that the following perceptions really are discernible:

Attack – the time line for the note to being audible to attaining  maximum volume.

Sustain – Once the perception of maximum volume is present, the length of time it remains.

Decay – The life of the Note / Vocal its length of time being perceived before if expires.

 All the above is achievable as perceptions to listeners on Stacked ESL's almost 60 Years since their being new.   

I have a pair of 1+1’s. For years I had a pair of Hafler DH-220s. They had plenty of power but they lacked “air” and depth. So just a few years ago I picked up an ARC VS-110. It might not have the horsepower but boy do those tubes sound great! 

You might consider finding yourself a nice tube amp of say 100wpc and see how that would work for you. 

Happy listening  

Your amplifiers are not destroying the spatial information you seek. I sold your 2+2 and many other stats. You don’t mention which wall you have them on and where the absorbers are… Typically audiophiles overtreat the room… w absorbers…typically also messing up frequently response by not using a broad band panel aka DEEP… diffusion on sides might help…

I agree 2+2 value plus $1K isn’t going to help much… and you will give up the magic midrange…

Just my $1.50

My first set of high end speakers were Acoustat 2 + 2… 1979? They were awesome but I instantly realized that a much better amp was required if I was going to keep them. So I bought a high current amp ($5K 19K today)… but after that purchase I couldn’t afford the speakers. I never got back to buying them.

With trade in and only $1K, that just sounds like a great way to trade and end up unhappy. Now if you can add $5K to $10K to your trade in, I’d start looking. But I am risk adverse.

Having owned Acoustat model 3M's, I can tell you that they are limited to the imaging that you describe, it is only once you change speakers that imaging specificity and IME, a host of other benefits, can be had. YMMV.