Category: Compressor

Request: TC Sustain + Parametric EQ

This one’s an experiment and there’s a real chance this initial version won’t work correctly, so keep that in mind if you’re trying this right away.

I took the service manual schematic that’s floating around and removed the portions related to the effect switching and the buffered bypass (or so I believe at least).


And from this I put together a fairly large layout.


There are a few uncertainties here. I grounded the now-unused parts of the LM339 (from the switching stuff I left out). The original uses an XR4212, but unless there’s something special about this particular IC I’m sure most quad opamps with a compatible pinout would work (e.g. TL074). The circuit contains two trim pots that presumably will need to be adjusted for proper circuit operation. The schematic also hinted at two resistors possibly having to be adjusted based on some setup routine (R53 and R60; see the schematic notes). I’m also assuming you’ll have a hard time finding a dual C100k pot, but a linear taper one is probably a second best.

I’m going to try building this (I do like those compressors), but I’m missing a few components and will have to source them, probably from over-seas. Let me know what your experiences are if you are brave enough to give this an attempt. (A quick google search seems to suggest the AA/119 is in fact the 1N60 germanium diode which I have a few of, but I’d like suggestions on a replacement for the BC558Bs).

Update (16.03.2013): Built this and it seems to work 🙂 All controls respond as expected, and there’s lots of compression and equalization happening.

SustainParametricEq board

First off, I had a small typo on the initial layout that has now been fixed.

I kept R53 at 1M, but didn’t have a 6M8 so I used a 10M for R60. Both trim pots were initially set at 50% and I didn’t try tweaking them as it seemed to work (I’ll experiment with these when I stuff this thing in an enclosure). I used an LF347 for IC1, though a TL074 would have probably worked just as fine. I found a couple of BC558Bs in my drawer so I haven’t experimented with any replacement for these.

Next step; how to fit this in a 1590BB without using a hammer…

Updated: 16 March, 2013 — 23:47

Engineer’s Thumb

Another compressor, this one by Merlin/ValveWizard. I chose to incorporate all the suggested mods on this layout. Let me know if you beat me to it building this one.

Update (06.08.2012): This might just be my favorite compressor thus far!

I was lucky when boxing this. Had I moved the jacks just a mm more in the wrong direction the board wouldn’t have fit the way it does now. But then again if I hadn’t added two extra columns to the vero for the wires it could have probably gone in vertically just fine. Anyway, really cool effect 🙂

Update (14.08.2012): Some of you have asked how to modify this to opt out of all the extra controls and have just the “ratio” and “level” ones. Here’s how to do t with the current layout:

1. Ignore the “attack” labels and instead add a 100 ohm resistor between them; a good place would be between pads (N2) and (O2).

2. Ignore the “release” labels and instead add a 1M resistor between them; for instance between pads (J7) and (L7).

3. Ignore the “threshold” labels. Add a 1M resistor in place of “threshold 1” and “threshold 2”; a good place would be pads (I9) and (M9), and add a wire link between “threshold 2” and “threshold 3”, probably best achieved by running a wire between pads (C1) and (M1).

4. Ignore the “treble” switch labels and leave these disconnected (you can also omit C3 and R4 as these are only used for the treble switch mod, but these can be left in with no detriment to the sound).

Updated: 21 December, 2012 — 22:33

Pigtronix Philosopher’s Tone

I’m weak for compressors and this one seems really interesting. Let me know if you try this layout before I get around to it.

Update (17.12.2011): mysticwhiskey verified this one already over at FSB.

Update (08.04.2012): Finished mine a few days ago. It really annoys me that I put +9v on the decal (I subsequently scribbled over it with a fat, black marker). Other than that I’m really happy with how the board-mounted pots worked out. And it sounds decent too, but not my favorite compressor.

Updated: 21 December, 2012 — 22:10

Request: Demeter Compulator

Did this a few nights ago, but didn’t get around to posting it until now. Not yet verified, but I’m fairly confident it’s correct (assuming the excellent schematic drawn by Bajaman is correct, of course).

Update (11.10.2011): Verified thanks to Hookey.

Update (28.11.2011): Finished my own build tonight. I’m generally enthusiastic about compressors, but this one sounds even better than expected. Hah!

Updated: 21 December, 2012 — 21:21


I did the “Janglebox mod” for the DynaComp in the past. This time Plesur over at freestompboxes traced an actual unit and produced a schematic, and here’s a vero layout according to said schematic.

Update (20.08.2011): Populated and tested the layout today. I had to reorient the Sustain pot, and the layout has been updated accordingly and is now verified.

Updated: 21 December, 2012 — 21:10

John Hollis’ Flatline Compressor

Here’s a new layout I’ve been working on over the holidays. The John Hollis’ “Flatline Compressor”.

Update (31.01.2011): Finished the Flatline layout today. I can confirm this one is working. Haven’t had time to play with it yet, though.

Update (18.05.2011): Boxed the Flatline compressor tonight. It sounds really nice, which somewhat makes up for the green enclosure turning out too dark for the transparent graphics. I tried a variety of different colored LEDs and found high brightness red and orange ones to work best, but your mileage may vary as this probably depends heavily on what LDR you use.

Update (20.10.2011): Fixed dead layout link.

Updated: 21 December, 2012 — 21:08

Orange Squeezer

I did a layouts for the Orange Squeezer a good while ago and forgot about it.

Update (12.02.2013): So I finally had a look at this old layout tonight. I did change the Sustain pot to a trimmer instead, but that’s the only thing I did. Works nicely and sounds pretty cool even. Verified as working!

Updated: 13 February, 2013 — 00:11
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