Just installed a PSU5 in my TZ yesterday. I had also obtained one of these ebay.com link: itm to defeat the expected staccato audio noise, but have not installed it. To my surprise, when testing after the PSU5 installation I find that I don't get that noise when powering off the machine! Strange, but I'm ok with that. I did install the 9.4CH ROM at the same time I did the other work, not sure if that makes a difference...

Wondering why I don't get that enhanced crack / staccato noise at power down when others do. Any thoughts?

Just to clarify,I do get the same single "crack" noise when turning off the machine as I did before installing the PSU5, but I don't get the staccato type crack noise some have reported after installing the PSU5.

I bought the same version of the board you got, which supports up to 3 speakers. I see now that the listing says it allows an AC input voltage of 12 - 15v.
ebay.com link: UPC1237 2 1CH 3 Channel Speaker Protection Board with Boot Delay 10A High Power

My question for you is - where were you able to find 12 - 15v AC on the sound board? I ask because looking at the manual the A-12738 sound board says it gets 20v AC from the transformer, and I don't see any 12 - 15v AC on that board. Is it ok to run this speaker delay board on 20v AC?

By contrast, the description of the version of the board that supports 2 speakers says is allows an AC input voltage of 10 - 18v or a DC input voltage of 12 - 24v.
ebay.com link: UPC1237 Dual Channel Speaker Protection Circuit Board DC 12 24V Boot Mute Delay

Ah, I see you mentioned Judge Dredd, so a DCS game with the A-16917 sound board. Even so, the manual for STTNG indicates this board has 18v AC on the board., still higher than 12 - 15v AC.

Can the version of the board that supports 3 speakers be run safely with 18v or 20v AC input? If so, perhaps this board would be more versatile in the number of different titles it could be installed in since it can handle more speakers?? Checking to make sure I don't burn it up installing it in games like TZ where 20v AC is on the sound board.