80’s AD-9 Trim pot adjustment


Silver Supporting Member
I’m wondering if anyone can tell me a method to approximate stock trim pot adjustment. I got one used that was adjusted. I messed with it now it’s a mess.

How should I set the knobs on the delay before I adjust the trimpots?

What do the two trimpots do?


Pedal Dan

The Island of Misfit Pedals
I always use the "Redneck R.F.D. Recalibratin Method" to adjust older pedals that have been messed with. Its not scientific but it always has worked for me:

1.Set ALL pots inside and outside to 12:00
2.Find an assistant to make single short notes on the guitar while your adjusting each INSIDE pot individually. Once you start you can tell which pot does what.(writing a diagram on a piece of paper helps)
3. Once you find a sweet spot then move to the next pot and repeat until all inside pots sound right.
4. Flip pedal over and twist the knobs. Listen to whats good and bad.... i.e. noisy repeats,osilates too easily, not enough repeats etc.
5. Flip back over and adjust accordingly.
6. Buy your assistant a beer for making this task easier than if you were doing it by yourself.
Even more redneck...

Get an 1/8" to1/4" adaptor and plug an old transistor radio or a Walkman in.

It's not rocket science.

JCM 800

Those are not trim pots for user adjustment. They are for calibrating the bucket brigade chips. Know anyone with an oscilloscope?

delay dude

One trim pot is for the maximum repeats (it is in series with the repeats knob). I set it for self oscillation when the repeats knob is maxed. A second trim pot is for the maximum delay time. Set it to 300ms (I put a digital delay in chain with the AD9 to see the exact ms). The third trim pot cancels the clock noise. You can use a software oscilloscope (something like the Visual Analizer VA64). Send a sinus tone into the pedal. When you turn the clock cancel trim pot you will see a curve at 3.5 kHz. Turn the trim pot (almost to the middle) until the curve disappears. Done.

(Sorry for my bad english - I hope you can understand what I mean)

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