BHK Pre--one channel louder

It does not matter the source. Using Mono recordings thru DAC and TT. Even with headphones, it seems one channel is louder (balance set at zero). I switch ears with headphones…it carries over to other ear. Same with speakers. To even the sound, I have to move balance 2 points to the rig
ht. I switched tubes around…no difference…any thoughts? All cables checked, connections, etc.

Is one jumper set at a higher voltage for the tubes? Not the 12v / 6 volt jumper. The other jumper. I’d check it to make sure

Current jumper 4ma or 5ma the same?

All jumpers the same. I switched to my spare set of tubes, puffed some air in tube sockets and waiting for the BHK to finish counting down

Ok…same thing. In the morning, I’ll hook up my Yamaha stereo receiver I use for my back patio speakers and see if the same occurs. If it did not follow when I switched ears, I would say it’s my hearing. BTW all mono recordings.

Is this a new unit?

yes…less than a year old. I just now noticed listening to many mono recordings. Of course…I can’t Stop hearing the imbalance

Gotcha, so you have had the unit for a while. I have a Sprout 100 and one channel is a bit louder than the other. Good luck.

Kindest Regards,

The little driver board behind each tube might be starting to falter. They are pull out pin boards in my early model.

If yours are removable, try swapping them keeping the tubes as they are.

Might be worth trying another set or one other driver board to see if that’s where the problem lies.

Less than a year old. Should be under warranty. I would contact PSAudio customer service.

3 years on them and I’d bet my last dollar they’ll figure something out for years beyond too.

Balance is set to center, correct?

I have the same perceived channel imbalance on my DSSr. but I just move my fat Arse to a position on the Sofa when the center image is locked between the two 901’s. My Koss Electrostatics headset requires me to offset the balance on a lot of material played thorugh the STAX or Koss Enegizers.

Ok. Update. One of the little boards behind the tubes was loose. I switched them anyway. I then put the original tubes in ( only 200 hours). I also took my photo lens blower bulb ad puffed out the connections of tubes and those boards.

Balance set at zero. I took my radio shack audio meter and checked the level out of each speaker with a true mono recording. Both levels equal. I then double checked headphones. Still off. I plugged headphones in my studio system. Same. The freaking headphones are off.

I grabbed and old pair and everything centered.

1.There was a preamp imbalance at first. I’m not certain all the tube switching, etc fixed anything or not.

  1. Some Beatles mono CDs favor one channel. Verified on my studio system

  2. System sounds centered now ( I did not move speakers)

  3. I’ve come to conclusion, I had many variables that may not have been zero centered. My issue is once I hear something, it does not go away.

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