I just got my brother a pair of Acoustat 1+1 in good condition. He has an ARC Sp11 and the large EMT turntable with original cartrage. The main question to this forum is what the power amp should be? Also, any other factors that are specifically important for these speakers? For example, would perhaps a step-up transformer be better than the phono stage of the SP11, what kind of.speaker cables? By brother listens to classical, jazz, and vocal, but not pop. He has a large duplex height wooden living room, does not care for excessive volume, but natural musicality and good imaging.
Thank you!
Thank you!
I found these quite difficulat to drive.
After many amps i modifed the 1+1 for passive bi-amp and used 2 NAIM 160s.
The question is whether the ARC can deliver the ex ces scurrent needed to drive a highly capacitive load.
dave
After many amps i modifed the 1+1 for passive bi-amp and used 2 NAIM 160s.
The question is whether the ARC can deliver the ex ces scurrent needed to drive a highly capacitive load.
dave
The general advice seems to be at least 100 watts per channel for Acoustats.
If you're looking for something newer that's moderately priced, the Parasound Halo amps handle difficult loads pretty well.
If you're looking for something newer that's moderately priced, the Parasound Halo amps handle difficult loads pretty well.
Not so much the power, it is the ability to deliver significant amounts of current. Remeber P = V x A x cos(phase angle). As the load gets more capcitive the cos goes toward zero.
The 50w NAIM played them better than many 200+ w amps of the day. The 70w NAIM 250 seemed to be able to drive any of ELS we had thru.
But passive bi-amping made a huge difference. Much more than the power thing would indicate.
dave
The 50w NAIM played them better than many 200+ w amps of the day. The 70w NAIM 250 seemed to be able to drive any of ELS we had thru.
But passive bi-amping made a huge difference. Much more than the power thing would indicate.
dave
What about good tube monoblocks or specifically a Futterman OTL? http://kayeaudiolabs.com/OTL_home.html
They have lots of really low impedance areas through the freq range and are really hard on amps. You need an amp that can handle 2 ohm loads and not burn up or shut down. Tubes are not the way to go especially an OTL. They don’t like low imped loads at all. Look for amps that have lots of output transistors as they tend to be able to deliver the needed current. Most amps are not rated for two ohm loads but if it can be bridged into mono and run a four ohm load it can run a two ohm load in stereo. It will get hot running that low impedance too!
Good Morning. Afternoon/evening, Klavimaniac:
Am probably bucking the trend, a bit, for high current amps and suggest a class D amp. An example would be the one of classDAudio, SDS-254 if you can find one or their newer ones, Mini GaN 3 Balanced Power Amplifier/Mini GaN 5 Balanced Power Amplifier. Note: Not advertising for them - just that I've used an SDS-254 without issues. There are also other higher power/wattage class D amps that would probably drive them. Unless budget is not a concern, then the older Krells, Mark Levinson, Classe, even the Acoustat TNT 120/200 should work well with the 1+1s. A conventional AB amp such as Bryston would probably work fine also.
As for the AR SP11, it has pretty good gain - 75dB (0.175mV input for 1V output), a step up transformer would only be needed if/for (very) low output moving coil cartridges to be used with the EMT turntable.
Speaker cables with low capacitance should be fine. There are so many varieties/brands that one would need try out for system/personal preferences. you/he can probably start with basic lamp cord and move up for them.
Thanks.
Sincerely,
Kingsley.
Am probably bucking the trend, a bit, for high current amps and suggest a class D amp. An example would be the one of classDAudio, SDS-254 if you can find one or their newer ones, Mini GaN 3 Balanced Power Amplifier/Mini GaN 5 Balanced Power Amplifier. Note: Not advertising for them - just that I've used an SDS-254 without issues. There are also other higher power/wattage class D amps that would probably drive them. Unless budget is not a concern, then the older Krells, Mark Levinson, Classe, even the Acoustat TNT 120/200 should work well with the 1+1s. A conventional AB amp such as Bryston would probably work fine also.
As for the AR SP11, it has pretty good gain - 75dB (0.175mV input for 1V output), a step up transformer would only be needed if/for (very) low output moving coil cartridges to be used with the EMT turntable.
Speaker cables with low capacitance should be fine. There are so many varieties/brands that one would need try out for system/personal preferences. you/he can probably start with basic lamp cord and move up for them.
Thanks.
Sincerely,
Kingsley.
Sorta of…
If you buy an off-the-shelf OTL, you are still driving the matching trafos in the ESL. But a direct drive tube amp is actually ideal to drive the panels with no trafos at all. This is what Accoustat used in their powered version of the 3 panel ESL. I had a set at home for awhile, they needed more work… much of which has been done here. But that s a very serious, very high voltage diy project.
dave
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Might work. When i was going thru ESLs the only Calls D amp was the original Infinity and it was not very good on anything.
They tend to be happy in low impedance situations, it is just a question of can it deliver significant current in excess of its rating into a pure resistance.
Power is not all that important in itself (only that in appliing brute force one does have the current needed, but atoften at a big price), it is the ability to deliver the extra current needed to mantain the power into that capacitive load… sufficient to cover the power loss caused by the large phase angle.
The power specifations do not really tell you enuff to decide whether it can drive an ESL.
dave
Dave, you say: "But a direct drive tube amp is actually ideal to drive the panels with no trafos at all. This is what Accoustat used in their powered version of the 3 panel ESL." So what's the conclusion? Can my brother somehow get something like that? He is an architect, not an electrical engineer.
Thanks!
Thanks!
The Acoustat TNT 200 should work fine with the 1+1s, Klavimaniac. (I know because I have them both.) As for Dave's comment regarding the tube amp for the X series, from what I've read the X series with the a fully working direct driving/servo tube amps driving (the ones that were made for that series) were one of the best sounding in the Acoustat line. There's a chap, I believe, who goes by the moniker/username of 'discopete' who has a set of the X/Monitor 3s with the servo tube amps and if you are interested, maybe search diyAudio for his posts and what he has to say about them... Acoustat servo amps .
The Acoustat TNT200 is a good choice, although you won't find one that's less than about 35 years old. Many are still running great, and service is available.
The Hafler Transnova series is also a good choice. Also designed by Jim Strickland, they are very much the "next generation" of the original Acoustat line.
There are many amplifiers that would be suitable. Much depends on your budget, tastes, and size of listening space/playing volume desired. But the general advice given that the amplifier needs to be comfortable driving low impedances is absolutely correct. Otherwise, instability and/or overheating of the amplifier may result, or at the very least, frequency response anomalies may be introduced by amps with relatively high output impedance (aka low damping factor), especially if the output impedance varies considerably with frequency.
The Hafler Transnova series is also a good choice. Also designed by Jim Strickland, they are very much the "next generation" of the original Acoustat line.
There are many amplifiers that would be suitable. Much depends on your budget, tastes, and size of listening space/playing volume desired. But the general advice given that the amplifier needs to be comfortable driving low impedances is absolutely correct. Otherwise, instability and/or overheating of the amplifier may result, or at the very least, frequency response anomalies may be introduced by amps with relatively high output impedance (aka low damping factor), especially if the output impedance varies considerably with frequency.
Hack into an Adcom GFA-5400! Once the 5400 is on your radar, you'll be tripping over them, as they're everywhere.
https://www.diyaudio.com/community/threads/ps-hack-for-adcom-gfa-5400.361693/
https://www.diyaudio.com/community/threads/ps-hack-for-adcom-gfa-5400.361693/
And I would suggest remembering that PR=V^2. When driving a low voltage sensitivity speaker, the amp's voltage swing matters if you want something beyond a very polite playback level.
The capacitive load most electrostatics present is a given. That's why I mentioned difficult loads, which typically encompass phase angle and impedance extremes.
If someone is trying to figure out the basic voltage swing of an amp from the power and impedance rating, I think my equation is just dandy.
Without something like PowerCube testing of the amplifier, most people are going by other users' experiences, which is what I provided. If mine don't matter, I'll go on my merry way.
Without something like PowerCube testing of the amplifier, most people are going by other users' experiences, which is what I provided. If mine don't matter, I'll go on my merry way.