Wednesday, 30 June 2010

DIY Boss PC-2 / Amdek PCK100 Analog Percussion Synth

Back at the end of the 80's I went in a music shop in London and on impulse I bought this wierd BOSS box that made weird bloopy noises... a PC-2 Percussion Synthesizer. It wasn't a difficult decision at the time since it only cost me £10 brand new boxed (I think they were trying to get rid of them) and it came with a free brand new BOSS HC-2 Hand Clapper pedal, although that seemed even less useful (though the guy did a good sales pitch involving a tale about a friend with no arms who had trouble applauding at gigs... :o)

Apart from a bit of novelty value I gotta be honest they didn't get a lot of use... I think the HC-2 got chucked during a house cleanout and the PC-2 was sold on ebay a few years back (and was amazed to get £100 for it). Well now I am kicking myself and wished I'd held on to these two collectables.

So when I saw the schematic of the Amdek PCK100 online (actually a kit form of the PC-2 sold by a Roland affiliate) I decided to try to make one and once again re-live boingy noise heaven.

On the page where I found the schematic I also found a photo of the PCB and decided to try to use it directly. With some manipulation in Paint Shop Pro and the use of Press'n'Peel PCB etching film I was able to make a copy of the board and after working out some workarounds (e.g. using BA6110 instead of ultra-rare BA662A VCA chip) I actually got it to work.. So in case you're interested is how I did it

1) I started off with this photo of the track side of the original PCB

2) Turned to mono, upped the contrast, then very carefully use the "eraser" tool to ensure there are good clean gaps between all the tracks

3) Marked drill holes with circles

4) Drop colour depth to 2 colours

5) Negative image and a few embellishments and its ready to press'n'peel

6) Laser printed etch-resist transferred to copper clad board using a hot iron

7) Etched, drilled and trimmed ready for components

I mounted the board inside a project box from Maplin. By the way I have a thing for Dymo embossed label tape :)

The Amdek user guide gives info on some mods to the board (VCO wave form change, mod waveform change) which I added toggle switches for. Usually the Sweep control is a center tap pot.. I didn't have one so I instead rigged up a DPDT toggle and a resistor to a normal pot so that the same effect could be acheived (although I am not sure it works so well)

The original board calls for a Roland BA662A VCA chip... you won't find one! you can use a similar BA6110 chip but the pinout is different. I found the following worked

  • socket 1 connect to BA6110 pin# 4
  • socket 2 connect to BA6110 pin# 2
  • socket 3 connect to BA6110 pin# 1
  • socket 4 no connection. BA6110 pin#3 connected to GND (pin 5)
  • socket 5 connect to BA6110 pin#5
  • socket 6 connect to BA6110 pin#6
  • socket 7 connect to BA6110 pin#7
  • socket 8 connect to BA6110 pin#8
  • socket 9 connect to BA6110 pin#9
Click below to get the full size PCB template to use directly. See the link at start of article for schematic, photo of top of the board and original PCK100 kit instructions


  1. This comment has been removed by a blog administrator.

  2. Thanks! I corrected the text

  3. Hello
    you can take out my text again
    because of the e-mail
    I have the hc-2 reconstructed
    and these texts do not usually write like we K├Ânen
    greet udo

  4. Thanks for sharing the info.

  5. Thank you very much for sharing, nice job!!!

  6. Hi, thanks for sharing.
    I really have to try this one on my drums!
    Do you have any Q1 and Q2 equivalent? I cannot find informations on them.

  7. @Olivier - yeah... 2SC945P transistors... take a look on eBay.. I can see a few sellers with some, pretty cheap. Cheers/Jason

  8. Oups! I meaned D1 and D2 in fact.... transistor is ok.

  9. I think I subbed 1n4148's for all the diodes

  10. Many thanks Jason

  11. hi,

    rather using the transistors mentioned could i use the bc547c transistor which is a general transistor npn???

  12. hello,

    The connections to the BA6110 is that on the board or have you connected them separably with wire?? Could you help and send me connection picture please at

    and if you can a parts list and a diagram of where everything goes but not in the schematic way but parts on top of the board diagram.

    1. I listed the connections in the description above. The BA6110 pinout is different to BA662A so you'll need to wire it to the board. Best glue the BA6110 upside down next to the socket "dead-bug" fashion before wiring it.

  13. Hello Again,

    I will also need pictures of the switch connections. please send a clear diagram if possible to my email sent earlier.



  14. Hello,

    If anyone has completed this unit could you send me clear pictures of construction and where the parts go please. my email is


  15. Hello ! do you have the parts lists and the designators ? what abou t the wiring scheme ? thank you !

    1. You'll need to check out the Amdek schematic and assembly instructions which you can find on effectsdatabase. See link in the blog above

  16. This comment has been removed by the author.

  17. Hi, i wrote from toronto , i want to buy this fantastic pedal clone ,the most important thing for me is the trigger in because i want to use with my roland tr 606.
    How much does it cost? do you u know the other boss / roland hc2 hand clapper?

    1. Sorry this one is not for sale (took too long to make compared with what anyone sane would pay for it).
      I got my original PC-2 with a HC-2 at gbp10 for the pair, new! unfortunately I gave the HC-2 away to a charity shop when I moved house years ago. TBH it wasn't half as much fun as the PC-2

  18. Have you though about making a small breakoutboard for the replacemnet IC? Maybe even use a surfacemount version so you get it as smal as the original chip?

  19. Hi sorry to bother you... im builbing this amazing clone but...can you elaborate a little on how you replace the center taped pot for a switch? thanks a lot in advance.

  20. This comment has been removed by the author.

    1. Hi Parts list culled from an original board and the circuit diagram


      R1, 2, 4, 5, 23, 28, 29, 33, 34, 38, 41, 42 47k 12 off
      R3, 15 10k 2 off
      R6, 7, 17, 21 1k 4 off
      R8, 19 33k 2 off
      R9, 11, 12, 24, 25, 30, 31, 35, 36, 40 100k 10 off
      R10 1M 1 off
      R13, 26, 27, 39, 43 22k 5 off
      R14, 20, 22 4k7 3 off
      R16 4M7 1 off
      R18 56k 1 off
      R32 220k 1 off
      R37 330R 1 off


      VR1, 3, 5, 6 100kA 4 off
      VR2 1MA 1 off
      VR4 1kB center tap 1 off


      C1, 2, 6 0.047 3 off
      C3, 11, 12 1 50v electrolytic 3 off
      C4, 5, 7, 15 0.001 4 off
      C8 2.2 50v electrolytic 1 off
      C9 10 16v electrolytic 1 off
      C10, 14 100 16v electrolytic 2 off
      C13 0.0022 1 off
      C16 0.0033 1 off


      D1 S5506G 1 off
      D2, 3, 4 DS442 3 off

      Integrated circuits

      IC1 4558 1 off
      IC2 BA662B 1 off
      IC3 NJM2904 1 off


      Q1, Q2 2SC945P 2 off

  21. Thanks - I finally managed to get a kit together

  22. hi,
    missed to buy the kit on tindie.. was already in the shopping basket but now its sold out :( any chance there will be another run or to get at least the pcb only?

    1. Hi - yeah they will definitely be back within the next couple of months. Cheers/Jason

  23. hi, wohoo. thanks for your answer and good news. cant wait :)