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Connecting a unbalanced output preamp to Krell FPB350 balanced amp

Hello everyone,

I own a Conrad Johnson 17LS and a pair of Krell FPB350 amps. The CJ has only RCA unbalanced outputs and the Krell has balanced inputs (either in their proprietary CAST configuration or a standard XLR connection). I've been trying to upgrade my interconnects and have been experiencing buzz and hum. I was wondering if anyone has a cable configuration that best minimises these problems. I have seen the "rane.com" suggestions and tried their configuration #17. I've tried other configurations such as 3 cores with a shield that is connected at the XLR end to ground and the RCA end to the return conductor/pin. I've also tried with only one end (XLR balanced end) connected to ground. None of these solved the problem though the second option above seems to have the least amount of hum or buzz.

Regards.
swcng2001
llira
2 posts
 
Hello, 
audio Research made line driver in past for this reason with unity gain. I use one to connect arc sp11 tp arc ref 150. It works and no hum.  Audio Research BL1 line driver is its name. Hope this helps
swcng2001 OP
6 posts
 
@llira,

Thanks. It seems the BL-1 is not available anymore. Yours must have given you many years of service.


gdnrbob
4,452 posts
 
As I said, call Jensen. They have great customer service. When I contacted them, I got a fast response to all my questions and even a discount on the regular price.
B 
sgonzalez33
13 posts
 
@swcng2001 
I know this is some time later but I have an extra ARC BL-1 if you're still interested in going that route. I used one between a phono pre and preamp. Worked well for me.
dave_b's avatar
dave_b
3,159 posts
 
Get a used Krell KCT preamp...dead quiet and extremely musical!  Krell amps are designed to be run fully balanced.  You will not hear what the amps can do unless you run Balanced!
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