BHK 250 Hum

Yes, correct. The RCA to XLR converters don’t “convert” anything. They just eliminate one of the conductors and you do not get the benefits of balanced.

Hi Paul,
Thanks for the reply on the XLR coverters. My main question though still remains. Why do I hear a hum in both speakers when connecting any source, be it the DirectStream or my Oppo BDP95 or my Mystere CA21 tube preamp via RCA to the BHK 250? When using XLR the hum is gone. I never ran into the hum with any of my other amplifiers when connecting any of the before mentioned components via RCA. I tried many different ways to narrow down on the cause. Everything plugged into the P15, everything plugged into the wall, only plugging in the DirectStream and BHK250, nothing else-both ways, directly into the wall outlet and via the P15, the hum was always audible the same way in the speakers. Only when I plugged nothing into the BHK250, with just the speakers connected would it get rid of the hum. I also tried removing the ground pins, with no noticeable change. Obviously, I am not the first BHK 250 owner that experienced that same hum when using RCA. I just did not see the cause or the remedy mentioned anywhere in this post and of course hope there is a solution to the problem.
Thank you for your help.

Kind regards,

Holen Sie sich Outlook für iOS

Because the the BHK 250 is fully balanced and the sources you’re connecting, particularly the Mystere are not. I have been down this same road with the BHK amps and those are the solutions I gave you earlier.

Hi Jack,

I understand that the amplifier is fully balanced, but why does it feature an RCA input when it doesn’t result in a hum free connection?
I had a couple of high end amplifiers in the past, of which none were burdened with any hum to my recollection when connected via RCA.
Maybe the were not fully balanced, but I believe they were!? I had a Mark Levinson 333, as well as a NewClear NC1000L and also a pair of Emotiva XPR 1in the past, and they were quiet without hum using RCA as far as I remember.
Well, if the BHK doesn’t like RCA connections, I guess my only two choices are to dump the BHK amplifier or the Mystere preamp.
Thanks for your help.

The only way to know if the amp is fully balanced is to look in depth at the spec sheet unless the manufacturer mentions in the ad copy. Many manufacturers offer XLR inputs as a matter of convenience so the customer doesn’t have to change cables. Same is true of many preamp manufacturers too. The Levinson is a dual Mono amp, as is the New Clear and the Emotiva’s are mono’s so different configuration. Have you looked at the Jensen transformers as they may solve your problem and let you keep the gear you have.

Look at the PB-2RX