Tuesday, 7 November 2017

Guyatone PS-021 Guitar Exciter / Compressor

A vintage pedal from the 80s.
I've removed the flip flop switching system and buffers (thanks Zach for the help).
Hopefully it will fit in a 125B box.
You can find original thread and schematic here.
Updated schematic is available in our Forum section. 
Thanks Dino for his explanatory video.
12/11 Layout Updated! Readded the input buffer as Aion's suggested.

... and the LM13700 version


  1. Replies
    1. not see Volume 2, only 3 and 1

    2. First - it is a layout. Not a schematic.

      Second - you have three lugs on your volume pot, yes? Lugs 1 and 3 connect to board as pictured. You take a wire to lug 2 and that wire is your output. Thus, the output comes from the pot, not from the board.

    3. very thanks for your explaining¡¡

  2. Nice! Just fixed the bass version for a friend and this is just a perfect effect. Dyna comp to simplified BBE Stinger to BMP tone stack. Sounds just amazing. Aion might be putting a RTS PCB out in a few months and if that'll fit in 1590B, i might get me one of those. If i find the time i may build this layout anyway.

    Had my eye on the schem, but figured i didn't want to take a go at it - as it is huge. Thanks Alex!

  3. Hello!
    Anyone have built it? I've just finished, but it didn't work as I heard in demos: it has a low level and distorted output. All the pot seems to work.
    In the schematic, the 22K trimpot looks strange to me. In all Dynacomp variants, it is only 2K. Maybe this could be a problem?

    Thank you!

    1. I don't think trimpot is needed at all. It was necessary for old 3080 ICs, because they had some sort of unequal inputs, LM13700 doesn't have that problem.

    2. Just verifying Aion's trace to my unit now. Trimmer is 2K2. NOT 22K.

  4. So, it's verified now? looks fine.