2. amps-preamps
  3. 1251337559

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

Showing 3 responses by amfibius

amfibius OP
282 posts
 
Thanks for your reply Almarg, I am finding it a bit difficult to follow your argument but what you say makes sense. To answer your question - every time I get sound from the woofers it sounds OK.

To clarify matters I am going to ask an engineer friend of mine to help measure the impedance curve of the woofers. I do not understand why the SS power amp is happy to power the speakers full range, but not happy to power the woofers alone.
amfibius OP
282 posts
 
Thanks for your contributions so far, Al and others. Just one question - what would the symptoms of protective shutdown be? Would you expect the amp to make some sound, or would it refuse to power up altogether?

There are a couple of things which I did not mention in my initial post. The first is that I had to use 10m speaker cable, because I don't have a spare pair of anything shorter. When that failed to work, I hacked up some rather thin gauge lamp wire with the same results. I would imagine that both cables would present the amp with a large resistive load (and large capacitative load in the case of the 10m cable). Would this exacerbate the problem?

Also, I know something about the internal configuration of my speakers. It is rather weird - one woofer runs off the crossover, and the other woofer runs straight off the binding post and is effectively full range. What would this do to an SS amplifier?

Also, why does the SS amp refuse to drive the woofer, whilst the valve amp is perfectly happy to do so? It seems counter-intuitive.
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.
More to discover