Bhk pre volume knob falls off

I just recieved my BHK Pre back from PSAUDIO after some warranty work.
When i pulled the unit out of the box i heard a rattling sound from within. Turns out there was a screw floating around in there. In the process of trying to get it out the volume knob fell off.
I called PSAUDIO and they feel the screw works to keep the volume knob in place.
They directed me an access channel underneath the unit that i could reseat the screw.

Challenges: getting the screw to stay in the screwdriver *my magnatized screw driver doesnt hold the screw

-the screw head is to large to fit through the channel

-screw very short and i cant figure out how it would help secure the volume knob.

Given this im wondering does the screw even have anything to do with the volume knob?

If the screw does secure the knob any hints on how to get it reseated given the screw wont fit through the access channel underneath?

Its too far away from the top of unit and i could open the bottom as it connects to some of the units innards.

Seems a dumb thing to send it back to them for as the Pre works just fine

Thank you

If you are even minimally handy you can fix this yourself. (Hopefully I remember this sequence correctly from when I had to repair a loose volume potentiometer mount in my BHK pre.) Remove the top cover (see illustration below for the screws to remove.) After removing the screws, remove the tube access cover and use that access to get leverage to remove the top cover. Watch out for snagging any wires that might get caught in the cover’s “leg panel” that the fastening screws attach to. Once the cover is off you’ll be able to see the little slot that gives access to the allen head screw that secures the volume knob. Insert the allen head screw just enough to get it started in the threads, insert the knob on the volume pot shaft, line up the screw with the threads in the shaft and tighten everything snuggly. None of this was hard to do, everything was pretty obvious and in plain sight once the top cover was off.

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Thank u
Looks to be what i call the bottom?
I unscrewed all the screws yesterday but couldnt remove the panel
It seemed boards etc were connected to it
Does only a portion of panel come off?

The entire top panel will come off after removing the screws on the bottom of the preamp. Here’s a link to video showing a PS Audio engineer taking the cover off a PS Audio dac that has the same case work. You won’t have to pull that black patch off the bottom and because you can use the tube access panel to get the cover wiggled loose you won’t have to use the threaded stand-offs to pop the cover off like is shown in the video.


Thank you
I never would have figure that out
Will try tomorrow
Really appreciate it!

Let us know if you’re able to access the screw hole for the knob’s setscrew. I’m almost certain the only way to properly access it is through the bottom. The guys downstairs use pretty long drivers in order to tighten it.

Thanks this screw is completely out.
Only way to get it back in…i think…
Is taking the top of unit off as screw wont fit through tunnel

I looked under the preamp and James is right about there being an access port for the allen screw that fastens the knob to the shaft. There is another top side access point from the inside of the chassis that I used in the above description. That top side access point has a slot that looks just about like the slot on the bottom. As I was inside the chassis doing a different repair it was easier for me to use the top side access port. As long as you have the right driver tool it will probably be easier to use the bottom access port. You’ll need a long allen wrench like one of these:

I can’t remember if it required a metric or “standard” size as I have both types of allen wrenches in my audio tool kit. Parts in audio equipment come from all over the world and you need both types available. I’ve often find mixes of metric and SAE sizes in one component.

If the screw won’t fit through the access slot you may have a different screw that’s on the loose other than the allen screw that fastens the knob. The allen screw for the volume knob definitely will fit through that slot - it’s tiny. Can you post a picture of the screw in question?

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Its definitely not tiny
Ill send pictures

Here is pix of screw

Did it make a clicking sound when the knob fell off?

Unless PS Audio has had a major change in the design of the volume knob since mine was manufactured, that is not the allen screw that fastens the volume knob. The screw that fastens my knob looks like this and is tiny, like 1.5mm-2mm:

Allen screw

That is not the screw, hence the fit issues.

The black screw could be one of the 6 screws that secures the micro-processor / stepper motor board to the case. (see photo) All the other screws inside the BHK preamp securing the mother and daughter boards are plated screws, silver in colour. The volume knob is secured by a very small Allen head grub screw to the stepper motor shaft (see photo). (The screws were said colour in my two BHK preamps but they may be different nowadays?!)
If your preamp has just returned from a warranty repair then send it back. You shouldn’t have make good a cack-handed repair.


Agreed, one shouldn’t have to self-repair what should have been done right the first time. Thing is, you end up doing it yourself because you’ve been without an audio system for a month or more and you are frustrated at the thought of another month of audio down time and another round of FedEx beatings.

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That’s not the set screw for the knob. At this point, you’re much better off sending it back to us. We’ll cover the shipping round trip for you and make sure it isn’t here long.


It was gone for 3.5 weeks and fedex lost it for 2 days.
But in the end probably best to send it back in.
At least they make that part very easy

Those screws all there. Thinking now it just fell in there from the repair station…just randomly