Guyatone ADX

Here’s another pedal bought as dead.

The pedal is powered with a 12V 200 or 500mA AC adaptor. It had a tube inside (that I removed later) and  12V is pretty ridicoulus for a tube that usually sees way more that 100V at its anode. I’m pretty sure the tube was only a marketing tool to sell the pedal. Witch such low voltage the current is in the µA region , a transistor would do way better in such application.

Indeed , puttin tube is great to increase the price of the product (Korg puts tubes in their electribes samplers …) even if the tube does nothing. Comsumers don’t ask questions and buy if marketing is good unfortunately .


however , the pedal is based on a BBD chip , the MN3011 and its clock. This chips is (was) usually used for reverb effect and even if the pedal states “delay” it’s a reverb. Longer delays are possible but become noisy as hell !

As shown in the schematic , the input control was to saturate the tube , but it only give poor effect and not that warm tube saturation that you’d expect from it. I removed the tube (such a waste of tube) and keep it for other projects.

this little thing had its NE571 fried, I changed it and it was back to life .  Working on the pcb wasn’t that easy , the traces were thin and compact. The wire weren’t strong enough and some broke.

this circuit offers a kind of “vintage” slapack delay and reverb , dirty  and a bit saturated.

Actually no much to say about it . I also had the newer version of it, the blue digital version. I wasn’t really convinced by it either.

here’s the schematic : GUYATONE AD-X SCHEMATIC



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2 responses to “Guyatone ADX

  1. Sean

    Interested in knowing where to get schematics for Guyatone pedals. I have a dead TD-X Tube Echo pedal but struggling to find a schematic.

    • actually Guyatone gives schematics. But I think the brand doesn’t exist anymore (but I might be wrong). I got the schematic from the distributor if I recall corectly.
      Nice to see that some manufacters still care about their products being repaired.

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