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Can I bi-wire Martin Logan CLS speakers?

Hello, Sorry in advance for my lack of knowledge. I read a lot of threads and other sites on the subject, and it appears that I'm up the creek without a paddle, but I just want to make sure.

I have a pair of Martin Locan CLS speakers, and a pair of Graaf iti 50 WPC stereo tube amps. My preamp is an EAD Theatermaster 8000. If I use one Graaf amp to power the two main speakers as in a normal stereo configuration, even at full volume it is barely enough to power the enormous power hungry inefficient electrostatic beasts. Since I have another identical amp, I'm wondering if there is any way at all to make this happen.

The Martin Logan CLS speakers only have two binding posts per speaker. The amps only have two binding posts per channel, four posts on each two channel amp.

Can I put one channel from the preamp into two amplification sections, then power each speaker from two channels to double the power?

I realize this is probably a pipe dream, but I had to ask. I'm not going to try it for fear of damage until I understand it better.

Many Thanks-

Victor D.
victord
6 responses Add your response
kr4's avatar
kr4
3,680 posts
 
You cannot do what you have proposed: wiring both channels in parallel on each amp/speaker since each channel will shunt the other. You can bridge them if you get/build a bridging adapter.

Or sell the amps and get ones with more power.
ed_sawyer
588 posts
 
I find it hard to believe 50wpc is not enough. I run my CLS with less than 20 and it's more than enough power for high volumes... (driven either by 845-based SET amps, 47Lab gaincard, etc. )

The ML's don't do biamping or biwiring, but if you bridge your amps for mono operation, then you could probably have about 150wpc to play with. (bridging nets more than the sum of the 2 stereo channels). Still, there's not much reason to have that much power... unless your room is HUGE. Mine ran fine with 20 watts in a 24 x 16 x 12ish room with no problems. Smaller rooms are even easier. I had them running full range, but also had subs augmenting the low end.

-Ed
johnk's avatar
johnk
1,975 posts
 
One driver 1 pair of wires, electrostatic panels like cls are one driver you can only biamp multi driver speakers with more than one speaker connector
dannylw's avatar
dannylw
172 posts
 
Even 150 is not enough power. Depending on the model of CLS you own you may get away with low power. However, most iterations of this speaker want to see something north of 150 on transients without the amp going into heart failure.
dannylw's avatar
dannylw
172 posts
 
Your question about bridging maycause a problem as well. Many amps when bridged can only deal with half the impedance that they could before. In other words if the speaker was nominally 8 ohms it now appears to the amp combination as 4 ohms. Depending on which version of CLS you own the amp could be seeing as little as less than 1/2 an ohm impedance. The earliest versions could be driven easily by tubes. The middle and later versions are somewhat unfriendly to all but the more robust tube outputs. All the later versions are power hungry if you drive them full range. I biamp some of the time with a separate sub which considerably reduces power requirements on the stat amp.
victord OP
1 posts
 
I guess I'm just going to have to live with it. The Graaf 50 wpc tube amp will do the trick most of the time, but on some recordings, even at full volume, it sounds like Dannylw described, heart failure. I have found that tube amps generally sound louder than solid state of the same wattage. Like double perhaps. So my 50 wpc tube amps sound closer to 100 wpc solid state. Probably just enough to get by. For movies I have 200 wpc solid state and that works just fine.

Thanks for all the responses.

Regards,
Victor D.
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