Calling on all Sherlock Holmes

Before sending my BHK Preamp for repair I wanted to tap the community for any information related to the problem Mark from Support and I have not succeeded in identifying.

Symptoms: The volume on my unit freezes after the unit is on for a period of time. It also cannot switch between inputs. It continues to play without the ability to control.

Temporary fix: Shut the unit down completely for at least 4 hours. All controls are then restored. If a startup is attempted without “rest” the countdown in the front panel begins and continues very slowly until it eventually stops before the unit can start.

Attempted resolutions: Changed tubes, changed firmware chip, replaced the preamp in my secondary all Schiit system with the BHK Pre. Connected to different everything the same problem persists.

Thoughts so far: The problem is related to the amount of time the unit is on. It works fine for between 4 and 8 hours, then the controls freeze. The behavior is consistent on two dozen repeated tries.

Has anyone experience similar symptoms on their BHK Preamp? If so, were they resolved and how? It is very odd behavior not seen before by PS Audio Support. Perhaps Bascom or others highly experienced with the BHK Preamp can suggest some leads to follow.

Very odd behavior I have not heard of previously.

I would just send it in. I doubt there is any easy in-the-field fix at this point.

I’ve had my BHK pre for about a year and a half and this has happened to me twice. Different from you though, if I do a quick reboot with the rear switch, it comes right back. I don’t have to let it sit for 4 hours or anything.

I’m not sure if you’ve already tried this, but I’d try powering it with a few different things. If you’re now powering it with a regen or conditioner, try plugging it right into the wall and see if anything changes.

1 Like

Thanks, James. I don’t feel so alone anymore. I have it running now. As soon as it freezes I’ll be trying your tips.

1 Like

It is the necessity to let it sit to reset which makes little sense to me. All computers get scrambled on occasion, but usually a power cycle will fix it.

It will be interesting to learn whether it makes a difference how the unit is powered.

Sometimes pulling a cord and letting units sit unplugged 5 or 10 minutes also helps. Your case seems extra strange almost like some other RF or EMI or another infrared Remote taking over. Perps covering the sensor after a reset and using touch controls or moving unit if your ICs will stretch far enough to see if it differs from a slightly different position.

1 Like

I had this problem just after I purchased my pre in 2018. Didn’t correlate an hr/reset time for it to correct and then happen, again, but reading your description it’s definitely the same symptoms. Service dept sent me a replacement microprocessor, updated firmware, tool, anti-static strap and instructions. Seemed to do the trick, however, I do get the same intermittent problem @jamesh experiences. I’d say I’m 97% fixed but it does happen on occasion and I’ve lived w/it.

At first, I phoned the service dept, followed by the following correspondence when I was troubleshooting. Read as most current email first w/older as you scroll. There are references to other threads, too.

From: Mark Simpson
Sent: Thursday, February 21, 2019 09:42
Subject: RE: BHK Signature Pre Volume Problem

As we discussed, I’ve initiated a zero dollar Sales Order for a new Preamp Firmware Upgrade. You should have that in 3-5 business days.

Sent: Thursday, February 21, 2019 10:16 AM
To: Mark Simpson
Subject: BHK Signature Pre Volume Problem

HI, Mark,

…I received a replacement microprocessor and I swapped it out approx. 1 month ago. Been on the road and finally able to follow-up w/you guys. Microprocessor did not fix the problem and it persists.

Following posts are from the original PSA Forum thread I found when this first started researching this.

Complete thread:

These 2 posts are the exact symptoms I’m experiencing:

Jun '17 I just started having my own problems. The preamp started normally this evening but when I tried to change the volume with the remote it didn’t move. I rebooted the preamp and the 45 second warm-up countdown took four or five times that long. When it eventually came on, it had the same volume problem. If I spin the physical volume knob it sometimes moves a click or so per revolution (or two or three revolutions). I unplugged the unit for 15 minutes and rebooted. Same thing. 45 second countdown took over five minutes. Volume knob mostly unresponsive and remote totally unresponsive, including input changes (inputs can be changed from front panel). It is not in Home Theater mode.**

Jun '17 I’ve had a similar problem(s) with my BHK preamp… Both times it was the small board/microprocessor that the stepper motor is attached to… First fault: a failed display - burnt-out component. ( Dave P sent me the parts and I installed the board and display and all was well for a few months ) Second fault: unresponsive volume ! ( Dealer sent me the new microprocessor and the musical bliss resumed ) …"

…Edited for format.

I was thinking spurious IR could be ‘crashing’ the processor. Good suggestion to try covering the IR eye and see if it occurs again.

1 Like

Some interior lights will about IR. But likely other remotes could be malfunctioning. Taking all away then finding the offender slowly would be a project.

The cut and paste job made things a little confusing. The last paragraph is Dirk. The “I just started having my own problems” described my issue. In my case the microprocessor update fixed the problem. It has not happened again, fortunately. Good luck with yours.

Yah, apologize. I quoted/linked posts when I emailed Mark. The formatting and links don’t paste in well, here. Thanks for pointing this out and clarifying. To the OP…the top part of what I pasted in was the final outcome.

Updated my post above using the editor features. Hopefully, now, it’s easier to follow. LOL.

1 Like

I can’t hold back, that my impression is, the DS DAC (excluding the Bridge) is clearly the most reliable PSA product (but I also didn’t notice nameable reports about the Stellar amps).

Maybe it’s just because things get obvious on a forum of which not many exist. But I personally never had any problems with any Hi-Fi component except the Bridge and the falling off RCA connector on the DS.

The funny part is if my only exposure to our gear was the reference pieces in the IRS-5 room, I wouldn’t see a need for us to have a service department. I’ve never once had a hiccup with any of the pieces in that room. Swapping out old tubes doesn’t count.

Tubes are maintenance items.

Sure, tubes don’t count. Who knows if possibly some issues are connected to shipping circumstances which are hard to follow (SW related topics certainly are another matter)

1 Like

Wild guess without knowing that board or really anything about the circuit layout of the BHK Pre but the way you describe this I’m guessing heat… Something fails when it gets hot (takes at least 4 hours to heat-up) and resets / corrects when it cools (takes 4 hours).

I’m not saying do this but… a test could be stop it from heating up. This can be done with pulling the case off and pointing a decently sized fan at it to move the warm air away. That is not without risk though.

I received advice a long time ago I stick to. If something does not do what it’s meant to do, and it’s under warranty, it’s not your problem and don’t make it your problem. Return it.

We bought a new dryer last Wednesday. It was delivered and installed on Thursday. It was not working properly. I did not start checking the plumbing or taking it apart. I called the company and a new machine was installed on Monday. It works perfectly.


I second @stevensegal 's take. It’s under warranty, it has a problem that can’t be resolved by rebooting, return it and let PSA take care of you, that’s what they’re known for.


Someone pasted on a paragraph from one of my earlier posts re: issues/problems with my BHK preamp. Unfortunately, the issues/problems escalated. PS Audio replaced the preamplifier twice. I no longer use the BHK preamplifier. Performance wise the BHK preamplifier was very special, a BIG improvement – sonically beyond reproach! ‘BUT’’, I wont expound on the subject because it’s a pointless exercise – the post, like previous posts on all my BHKs, will be redacted and/or pulled. So I will keep schtum!


Thanks to everyone who contributed their experience and suggestions. I tried all the recommended tips and, so far, cooling by putting small, quiet PC fans at one end of the DSD DAC/Preamp stack (BHK Pre fully clothed) are preventing the issue from happening.

Just like it’s best to judge SQ by listening to an audio device in our environments, difficult issues need as much diagnosis as possible done in the environment where the device lives. Unlike washing machines, audio devices live in an ecosystem far more complex than a washing machine. An outlier issue is often not easily replicated in the repair shop. It may be something else in that ecosystem that is the problem, not the seemingly problematic device itself.

Even though the BHK Pre is in the open, with only the DSD DAC under it with isolation feet raising it for separation, my unit appears to need more cooling to keep it from exhibiting the volume/input freezing behavior.

The issue is not normal behavior but at least when I send it in the techs will have an additional bit of information to identify the failing part.

Thanks again, everyone.

A good omen from my desert community in Palm Springs