DIY Guitar compression and sustain pedal

[Nordic]

Great, my wife said this morning, maybe it will be third time lucky as I was getting a bit dispondent over failure after failure at trying to get a working guitar compression pedal build.

Well, she was right.... This time te build was easy due to a more sensible layout, and it was actualy smaller than the previos version which was too tightly packed to solder properly....

I will likely play around with capacitor values a bit to get the exact sound I want, but I am helluva impressed with the unit... it sustains like a bat out of hell and is pretty smooth... realy brings out the quieter strings on my ESP. And what surprised med more than anything is that is is quieter than the original MXR DynaComp units, and that is before it ios boxed... I had to turn all the knobs to max to get any real noise out if it, and even then it was realy low...less than the average hiss from an LP player...

At that max setting it adds a nice crunchy bit of distortion too...
And the sustain feels like it lasts forever...
Total parts cost exluding case was about $7

[Nordic]

Hi guys, I was out today so, I have not been able to post agian...
Something has been nagging me...

I did not include instructions for those new to eagle...

When you open the board file, please hit the ratsnest button to fill the ground plane... You could also type the command ratsnest and enter...

To print for normal photodevelopment or iron on transfer;
Click
View>Display/Hide layers
Untick Top, tplace and bplace (the last to will also automaticaly hide t and bname and t and bvalue... click ok do the change.
The top layer can be done with simple wire links
You should only be looking at the frame and the blue traces and green pads and vias.


Now you are ready to click print, a little dialog window pops up, make sure only black and solid is ticked, and scale factor is 1, then you are ready to print.


To get high quality prints from eagle, google and download DoPDF... it is a free, virtual, printer driver... it creates PDF documents as an output and can be set for several hundred if not thousand DPI.... then just print the PDFs produced.

I appologise for the silkscreens not being done pretty but it was late when I finished and I just wanted to get it out there... to save people time wasted on some of the other designs posted online for this circuit.

As for parts selection, I didn't have any 10nf caps so, I used the 22nfs I had... no problem, in fact I'm going larger values for the next one.... and the output cap also needs to increase to I would guess about 1uF to keep the bass in the sound, the 1nf cap needs to be reduced possibly to half that (470p) to trim back the high frequencies a little... this is one very addictive little box...

Today I found what I was looking for... an Original Electro Harmonics Big Muff Pi from when I was only a boy (my dad was a drummer almost all his life so there was always band stuff around the house...) It is a little tarnished and scratched from standing in the garage for now almost 20 years.

I visited my mom today in the house I grew up in, we decided I am going to move back there and take over the house as my mom as battling the big C and can no longer stay in such a big house... so I will have all the time in the world to scratch out more such lovelyies... allready spied 3 forgotten tube amps in varying stages of wire decay .... going to have my hands full and my old workbench back from when I was just a boy... It used to be my granddad's...who also built amplifiers and all kinds of wonderfull machinery. some of the drawers even still have some vintage caps and from his old metal working tools... working with those things is very special, it feels like my ancestors live again through me...

[greenmathew]

I will suggest you to go through the audio video directory before proceeding.

[tschrama]

Hi Nordic,

I tried to built a diy compressor/sustainer for my guitar last year, just using discrete compenets , with a JFET as variable resistor.. I never really succed, ... I would really like to have a few on your schematic.. could you post a BMP or JPEG or GIF picture of your schematic?

chrzz,
Thijz

[Nordic]

sure... I also had endless problems getting the first working prototype...

You can also open the files useing te free trial version of eagle from cadsoft.

[cllvt]

Hi Nordic,

I recently discovered this forum, through searches on Compressor Pedals, etc. and ended up at this (interesting) thread.

This is a great site, and I am not sure why I did not locate it sooner, but I am glad I eventually did. Thanks for the effort you put into this pedal, and sharing it with the masses.

I was wondering, since it was quite a while ago now that the thread started, if you still use this pedal as posted, or have made any mods? Anything that you are especially happy with, or unhappy with ?

It is my intention to build this pedal. It may take me a while, as although I have messed around a lot with tube amps, printing circuit boards, layout, etc. is all new to me (and a bit overwhelming at this point). Any suggestions, or additional/new info about this pedal is much appreciated.

Thanks,
Chris

[cllvt]

Hi Nordic (or anyone),

I am a liitle confused over what "R20" is as well. It looks like some sort of large trim pot or something, but in the schematic it looks more like a switch with "A-E-S"??

Sorry for the questions, but as I mentioned this is pretty new to me. Thanks,
Chris

[Nigel Goodwin]

R20 is a preset potentiometer.

[spudd905x]

I hope this thread is still active! Can anyone tell me the value of C10 and the setup proceedure for the trimpot?

[naku]

I need the C10 value too. I will try some values but i would love to have this value. Are u there Nordic? Hope that u are ok and thank u very much. I would love to see some pics about your dad's lab