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Soundlab Speakers - Budget Amp Suggestions

I have tried to read as much as possible about different types of amplifiers capable of driving electrostatic speakers. Thanks to everyone for the great articles and discussions. In particular, I am looking for a ss amplifier that can drive Soundlab speakers. The Soundlabs have a low impedance at high frequencies and a high impedance at low frequencies. A high power ss amp that can drive difficult loads appears to be the ticket (I'm not interested in tube amps). High current is needed for the high frequency/low impedance (but not necessarily high power) while the high voltage (albeit at lower power) can drive the high impedance at low frequencies.

While looking for speakers I came across the Soundlab speakers and really liked the sound. I basically blew my budget on them, which for me is not a bad compromise because I don't want the speakers to be the weak link in the chain.

So this is what I have:
1. Two Soundlab A-1 speakers (1992 vintage)
2. One Soundlab B-1S subwoofer (pre 1990) - This is a stereo subwoofer having two separate inputs to drive each interior panel.
3. The A-1s have the toroidal and impedance upgrade.
4. I had all the speakers reskinned with the px mylar.

There will be some type of crossover between the A-1s and the B-1S (the frequency and type of crossover is undetermined at the moment)

I believe that having the B-1S reduces some of the constraint of having the highest power amplifier to drive the A-1s (e.g. 500-600W) since a lot of the bass will be coming from the B-1S. I was told to limit the power to the B-1S to a 400W or less ss amplifier. I am thinking that perhaps I could get away with a lower power amplifier for the A-1s because of this scheme. Please let me know if I am wrong.

As I said my budget is limited. I have about 1.2K and perhaps up to 2K to spend on an amp. The amp I have targeted is a Sunfire Cinema Grand Series II 5-Channel amplifier that outputs 425W a channel. The channels driving the B-1S won't be delivering a lot of power as the impedance is 16 to over 30 ohms. The amp should be able to drive the A-1s adequately. As a side note I have a couple of amps (Crown K1 or Citation 7.1 which output between 300-400W) that I could use to drive the B-1S if needed.

Are there some vintage or other budget amps that I should be considering. Is my analysis wrong? Any suggestions on crossover frequency? I appreciate any and all input. I want to thank every one in advance for their thoughts.

Regards,
GWHO

gwho
gwho OP
47 posts
 
Thanks Atmasphere. I will keep this in mind. It does point out the difference in tube vs ss for driving a varying impedance speaker.
grannyring's avatar
grannyring
6,464 posts
 
Gwho, you will simply need to try one of these amps and decide for yourself. I liked the CJ and Sunfire and know you will find them quite acceptable. My experience is that tube amps have a harder time with the highs where the impedance drops, even with the mod that I did perform.

My room is 18x24 and with 100-125 tube watts it would clip in the highs on difficult music like piano and orchestra. Clipping would occur at levels 87db and higher in my room.

If you are lucky enough to get a Sig600 and decide to sell, they typically sell in a couple of days.
tthomas
36 posts
 
One thing I forgot to mention, every SS amp I have ever used with my SoundLabs has heated up a lot when I have done a lot of listening until I got the Odyssey amps. They barely get warm to the touch with my normal listening.

I will tell you that the best I ever heard my speakers sound was when they were hooked up to a pair of atma-sphere amps. Unfortunately, they were also out of my price range. Maybe when my boys are finished with college....
gwho OP
47 posts
 
Thanks for all of your responses. I learned a lot. Grannyring I will definitely take your advice. I am going to try the suggested amps until I find one I really like. I was looking at a 600x2 on ebay but it was pulled from the auction. I am also looking at the Odyssey. No Innersound or CJ in sight or price range. Ideally, I am going to sell some of my stuff to allow me to purchase two amps simultaneously to compare/sell. I will be patient as it appears that the amps only show up sporadically. Of course these funds will likely get siphoned towards college tuition. I can always use the other amp on the B-1S until I settle on a choice. Here's hoping the economy starts improving!

Perhaps my next topic will be preamps/room correction but I am not prepared for that now.
atmasphere's avatar
atmasphere
11,760 posts
 
Grannyring, what mod did you perform? Did you remove the big resistor?
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