I have a BHK signature preamp, about four months old. Recently I have noticed a high pitched whine from the unit that is annoyingly audible from my listening position (about six feet away). I’m pretty sure it was not making this noise when I first received it. Just to be clear this is not a noise through the speakers; it is a noise generated by something in the preamp. It stays at the same level regardless of where the volume is set, but it disappears immediately when I put the unit into standby by pressing the button on the front. If the unit is warm, the noise comes back right away when I turn it back on. It is there while the preamp goes through its 45 second warm-up cycle and gets a bit louder when the warm-up cycle is over and the unit clicks on. If I turn it off using the switch on the back, the noise disappears and does not return until after the 90 second warm-up cycle is over.
Any ideas what could be causing this? Is it normal behavior and I just didn’t notice it until recently? Could it be tube-related?
I experienced your situation with a Quad preamp and I tracked it down to a tube. No noise coming through the speakers just from within the amp… Bad connection on one of the pins. By moving the tube slightly I could alter the frequency of the whine.
I changed the tubes and I also made sure all the socket connections were tighter…
The tube was also causing the transformer to make a noise.
Sorry to hear this!
Please reach out to us at service@psaudio.com with your serial number.
We’d like top take a look at the unit to make sure that it is not malfunctioning.
Thanks,
Thanks for the advice and info, all. I think I’ll try messing about with the tubes a bit before I think about sending the preamp to Boulder. It’s been a busy week but I should have time in the next few days to open it up, try different tubes, etc. (I’ve got the Tungsram tubes that came with the preamp from Upscale Audio still waiting to go in.) The sound coming out of the speakers is still wonderful, so its hard to get motivated to part with it, even temporarily.
Just thought I should close the loop on this. I changed tubes, tried a tube damper, nothing worked, so I finally sent it back to Boulder. The PS Audio techs did not succeed in replicating the problem, but they did replace most of the innards of the preamp. I’ve had it back for a couple of months now and it has been much quieter and trouble free. I did have to break it in all over again.
The level of customer service I have experienced from PS Audio is truly outstanding. They paid for shipping both ways and basically gave me a new pre-amp, even though they could not find a problem. Wow.
I’d like to resurrect this topic as weather has become warmer and I’m experiencing this same issue, except now the high pitch sound now is audible both from the machine and the speakers (gone from speakers once I muted the volume). I had this issue soon after I bought the bhk preamp just over a year ago, it then actually went ok after I took out and reinsert the tubes. Also was quite sure it wasn’t audible through speakers before. Anyone experienced the same? My local 1 year warranty had expired less than 2 months ago.
Thanks. I tried pointing a fan to the bhk preamp. As long as the temperature gets lower, that noise is gone. Have tried it eiyh the stock tubes and a set of Mullard and results were the same. Something inside must be very sensitive to heat.
This is absolutely a wild ass guess suggestion, but I remember someone from my audio club once mentioning this pertaining to one of his components (non PS Audio).
He found the toroidal transformer to be not even finger tight. Gentle snugging of the nut was the fix for him.
Thanks! I tried lifting up the bhk pre and couldn’t find any screws for the transformer. Guess will need to open up the case but that’s not something I’m gonna do. What I do now is to point a fan to it for 10-15 mins before turning it on.
No, never bothered to send it in as I’m a believer that the fix could be worse than the problem that you can live with. Also, the noise would go away once I reset using the rocker switch on the back. Lastly, I notice the noise would come when I plug in or take out cables while in standby mode so I learned to avoid doing that.
Thanks @Excelgam. Good that you know how to avoid it consistently. Does it happen also when it’s hot in standby? For me it’s become a usability issue and I hope PS Audio has a fix for it.
I found this thread while google-ing PS Audio BHK preamplifier whining. I too experienced this problem when I decided to replace the stock vaccum tubes after ~2500 hrs of use. Taking proper precautions, I replaced the Psvanes with pair of platinum grade Genalex 12AU7s from Upscale. I turned on the rear switch and after a minute pushed the front panel switch on and the whining started exactly as in Excelgam video. This whining was NOT audible through the signal path. I checked to make sure the tubes were seated properly and it was. I tried power cycling without success. Since the whine was annoying, I put the Pre on standby then turned it off leaving it powered off (not in standby) overnight. The next morning it turned on the back rocker switch then after a minute pushed on the front switch - no whine!! For 2 days, I left the Pre on play music to break in the tubes, no problems. So I put the Pre on standby mode. The following evening, I pushed on the front panel switch and the whine is back! Once again in put it on standby then turned it off completely. Next day I turned on the preamp and took it out of standby while it was still cold - no whine again! So it seems to occur when the Pre is warm. I used a fan to blow cool air on the Pre but that did not stop the whine either. The only solution was to power it off and allow things to cool down completely (I did not try different cool down times).
Finally, I decided to try a different set of tubes. I got a pair of SLN grade 12AU7C’s from (RAM Labs) tubeaudiostore.com. I replaced the Genalex with the 12AU7C, turned on the Pre and took it out of standby - no whine! Played music for a few hours and then left the Pre on standby when I was done. The next day when I took it out of standby mode there was no whine! It has been working normally for the past week.
I contacted support they kindly opened an RMA for me. Their hypothesis was it may be a bad regulator. Upscale did not think it was an issue with their 12AU7’s but I noted that the Genalex tubes had different construction than the stock Psvanes. They have single top insulating spacer vs the 12AU7C’s from RAM Labs which had two top insulating spacers like the original Psvanes.
I am trying to decide if I should send in the Pre for warranty repairs. What do you all think? I might try putting the Genalex’s back in to see if starts whining again.
