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Has anyone bi-amped with a Cary SLP-05?

I have this rather weird problem I am hoping the collective wisdom of Audiogon will be able to help me sort out.

The SLP-05 preamp has a pair of RCA outputs, and a pair of XLR outputs. I recently tried bi-amping using both outputs, and the result is the SS power amp always fails to work, no matter what output it is connected to. Here are the configurations which I tried:

SLP05-> (RCA)-> Cary CAD2000-> speaker
(Full range). Result: success

SLP05-> (XLR)-> Cary CAD200-> speaker
(Full range). Result: success

SLP05-> (XLR)-> Cary CAD211AE-> mid/tweet
SLP05-> (RCA)-> Cary CAD200-> woofer
(Bi-amped). Result: CAD211AE works, CAD200 produces no sound from the woofer.

SLP05-> (RCA)-> Cary CAD211AE-> mid/tweet
SLP05-> (XLR)-> Cary CAD200-> woofer
(Bi-amped). Result: CAD211AE works, CAD200 produces no sound from woofer.

SLP05-> (XLR)-> Cary CAD200-> mid/tweet
SLP05-> (RCA)-> Cary CAD211AE-> woofer
(Bi-amped with valve amp on bottom). Result: Now here is the interesting thing. Put the SS amp on the mid/tweet and the valve amp on the woofer, and it works! I am succesfully bi-amping!

Now obviously this is not what I want, because I would rather have the SS amp on the woofer. I checked and rechecked the connections and there was no problem. I swapped RCA and XLR cables to my spares and there was no problem. I swapped speaker cables and there was no problem.

I even borrowed another two SS power amps and the result was the same - each time, the SS power amp refused to power the woofer in bi-amp configuration.

I am wondering whether there is something about the higher input impedance of the valve amp that makes the SLP-05 preferentially drive it.

This problem has me beat. I can't figure it out. Can anyone help?
amfibius
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almarg
9,670 posts
 
Addendum to my previous post: I see on this spec sheet that the 211FE's balanced mode input impedance is listed as 300K, not 300 ohms, so the indication in the manual of 300 ohms is most likely a mistake, and using the balanced input is most likely fine.

Regards,
-- Al
silverlight99
3 posts
 
Almarg - thx very much for the response, most helpful. slow delay as I didn't get a notifier for a response (don't know if that's a possibility on this forum). so I'm now getting closer to giving this a run. The speakers I'm using are the new eFicion F300's. they're an excellent speaker, with two separate units - bass and then mid/high. I'll check with the manufacturer if they're both rated at 8 ohms and how consistent. I will let you know what success I have! I'm guessing as a check if I set up the system without the attenuator on the bass from the Spectron's I can measure the actual voltage arriving at the speakers as a confirmation, but not sure.
amfibius OP
282 posts
 
Silverlight (and Almarg) I thought I should post a follow-up to this thread, given that it was me who asked the original question.

I have since bought a pair of JL Audio F110 subwoofers, and a Behringer CX2310 crossover to remove low bass from the main speakers. The result has been a substantial improvement in bass clarity up to the midbass, and improvement in dynamic headroom of the system. The cost is from loss of midrange and upper treble resolution, as well as an annoying hum. No doubt this is due to the poor quality of the Behringer. A Marchand is on the way.

I think a much better solution is to forget about bi-amping from the SLP-05, and buy an external crossover. It would be even better if it were possible to bypass the internal crossovers of your speaker and go active. The extra cost of doing so is negligible, since you already own two pairs of power amps.
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