Amp Recommendations for Acoustat 1+1s

Hi all,

I juat scored a beautiful pair of Acoustat 1+1s in an auction last week (thanks AudiogoN!) and am looking for a suitable amp.

First, I have to tell you about the Acoustats. They were one of the last 3 pairs of 1+1/2+2s that Acoustat made. The owner was a friend of the folks at Windham Hill Records who were friends of Jim Strickland. They asked him to make three more pair for their personal use. Mine are in MINT condition with beautiful rosewood bases and brand new black socks ordered from Italy. They also have the latest "red" medallion transformers. I'm just smitten...Can you tell?

Anyway, I'm currently driving them with an Adcom GFA-555II and it sounds great, but I know that I could do better. I also know that the Acoustats are famously difficult to drive. That being said, I hear of people recommending everything from moderately powered tube amps to high current monoblocks. Do they need current (solid state) or voltage (tubes)?

I should also mention that my room is quite large. It's 25'X35'. The Adcom doesn't seem to have any problem driving them to concert levels and the "clipping" indicators on the front of the amp never so much as flicker. The amp also doesn't get particularly hot - although it does get warm.

I was thinking about finding an Acoustat TNT-200 since I know that it was designed specifically for the Acoustats.

So, what would you recommend (less than $1,000...the cheaper the better!) to extract the best from these speakers?

I appreciate your collective assistance.
I was thinking of buying some of these a while back, has some STRONG reccommendations for KRELL-KSA 50, as well as Forte 40a ( i think that was the model)

Mostly, the reccommendations were for solidly build CLASS A amps, they seem to work better with electrostatic because they can handle 2 ohm loads which these can drop to
Enjoy, as I have a pair of Acoustat X speakers, each with it's own servo charged built-in amp.

Great sound, could use some help with base, though.

I use them in two channel HT.
I would think the 1+1's would need quite a bit of power to play loud in a large room. Your Adcom seems up to the task, and frankly, under $1000, you may not do a lot better... Maybe adding a good subwoofer system would be something to consider... or using a decent tube preamp with the Adcom amp. Enjoy, the Acoustats are very nice speakers!
I'd vote for the Acoustat TNT 200. I owned Acoustats and drove them with this amp and they sounded great. If you can't find one, the new Hafler designs are based on the TNT 200 Trans Nova circuitry and I believe they would be great too.
Consider the Adcom GFA-5802 at about $875 used on Audiogon. I never tried it on the 1+1, but experimented with it for a long time on my friend's pair of Magnepan MG 1.6QRs. The 1.6QRs are very hard to drive, but the 5802 drove them very well and delivered a non-fatiguing, rather musical sound with relatively low coloration.

The low power Krell KSA-50 will not work. I tried the KSA-100 on the MG1.6QRs and they did not work. They are stable down to 2 ohms, but stability without the current does not solve your problem. As for a TNT, I see more potential issues buying an amp without a manufacturer to service it. Electronics are more likely to require service than speakers.
The Hafler 9505 is the updated TNT-200 and was designed by Jim Strickland. You should be able find one for less than $1000 with no trouble. I've owned both of them and the 9505 is considerably better. Drove my 2+2s easily for the past 7 years. I also own 1+1s and they take more power to drive than the 2+2s.
I use a Music Reference RM-9 tube amp (KT-88) on mine. 100wc/ch in a small/medium room. Sounds great! Use the 4 ohm tap.
I'll second Elgordo's comment on the Hafler 9505. I've used one for 7 years or so with Maggie 1.5's, 1.6's and now 3.6's. Outstanding sound IMHO and excellent durability. 250wpc @8 ohms, 375wpc @4 ohms. Rave review in S'hile in '92, including Sam Tellig, and many other publications. Now sold mainly for professional use and used in many a recording studio, since Hafler has exited the consumer market. This amp deserves more recognition.
I'm using a YBA DT on Acoustat 3s and it works extremely well. I used to use PS Model 2 Blocks in mono and they literally caught fire when I drove them hard. The Acoustats draw a lot of current and the YBA is up to the task without any hint of imaging loss and the bass is incredible.
Thanks everybody. Sorry for the delayed reply. I was in an auto accident last week and have been trying to deal with the insurance company, etc.

I still didn't get a clear answer of whether a slightly lower rated (wattage) tube amp delivers the necessary voltage to drive the Acoustats or if it's strictly wattage and current that make the 1+1s go. Audiokinesis?? (Duke)

Anyway, I've contacted someone who appears to be parting with his TNT-200. I might try that first and take it from there.

Elgordo - those 9505s are hard to find. They come up very seldom and seem to go pretty quickly. Is it that much better than the TNT-200?

Plato - I like the idea of going with a tube pre and sticking with ss for amplification. I'm hearing some thickness in the midrange, particularly on female vocals, and I'm also hearing some graininess in the upper registers. I was thinking that it was probably the amp, but now I'm not so sure that it isn't the preamp. I'm using the GFP-555II preamp. I know, it sucks, but I picked it up on the cheap. In fact, my net cost (after trade) for the Adcom 555II amp and 555II preamp was $200 for both!

Add the $650 I paid for the Acoustats and $55 I paid for my Sony ES cdp, and it comes out to be a pretty nice little system for only $905!

Thanks again everyone.
I think you need lots of current for the 1 + 1s. I had a pair in the mid to late 1980s and loved them. I also used an Adcom 555 amp but also used a Janis W1 subwoofer - made a huge difference as this freed main amp from a lot of work. With a properly set up sub (I now use RELs and run main speakers full range)and cut off point at around 70-80 HZ, you should be able to use a number of amps. I would stick with SS (yet Im a tube-a-holic) with these particular speakers but would seriously consider a good tube pre-amp and even no pre-amp - go passive - Placette Audio is an excellent choice and I use one with my 300B amp.

The 1 + 1s do not have much bass and what's there does suck up a lot of current. You will have a much broader range of amp choices if you get a good subwoofer and cut off the speakers at 70-80 HZ. I think lots of current is needed more than high voltage. Good luck, these are great speakers for a large room.
Hey G. Unless the guy is giving you the acoustat amp,forget about it. It will certainly drive the 1+1's and make some noise, but making music?....its just plain bad!He would have a tough time giving it away. Try a used Bryston 4b.....they are musical, reliable and sound great with acoustats.
I owned a pair of 1+1s for about 10 years.
They were in a fairly large quite live room. Depending on what you are looking to achieve, I can tell you that they are quite revealing of the amp they are being used with.

In no particular order:
Adcom 555 - Enough power but not very good sound.
Conrad Johnson MV-55 - By far my favorite providing rich, beautiful sound. Weak in bass where it didn't take much control over the speaker.
Conrad Johnson Premier 11A - Better bass than MV-55 and a bit more power but in all other ways I preferred the MV-55.
Acoustat 120 - Enough power and pretty good sound with tubed preamp.
Sonographe 120 - About the same as Acoustat 120 again with tubed preamp.
Motif 1001 - About the same as Acoustat 120 again with tubed preamp.
Krell KSA50 Mk.II - Brought out the bass like no other amp I used, in other ways about the same as Acoustat and Sonographe (with tubed preamp.)
B&K monoblocs - Plenty of power but just ok.
I found the Meitner 55 and a Creek integrated too low powered (though the Creek was quite good sounding).
I do think the 1+1s like tubes somewhere in the line.
And as you can tell I found quite a few amps worth using.

I would be somewhat cautious about using Magnepan experience as a guide to how Acoustats will sound with certain amps. My experience is that they don't necessarily pair well with the same amps.

Enjoy the Acoustats - they are great speakers and great fun.