Really Cheap Compressor

Tomby · Post by **Tomby** » 02 Jun 2010, 13:31

Thanks for these explanations.

I have to say the pedal is really convincing already. I just found it too bassy, and comparing to the sample posted here it sounds different.

Anyway, I'll test some different input capacitors as you're suggesting.

Thanks!

Tomby · Post by **Tomby** » 02 Jun 2010, 17:34

mictester wrote:
Don't waste your time worrying about resistor types - as long as you have the right values, the circuit will work well. However, carbon composition types will add to the hiss from the circuit, so are best avoided, and we don't need their bogus "mojo" factor.

I was more thinking about metal film resistors than carbon comp ones.

mictester · Post by **mictester** » 02 Jun 2010, 22:47

Tomby wrote:
mictester wrote:
Don't waste your time worrying about resistor types - as long as you have the right values, the circuit will work well. However, carbon composition types will add to the hiss from the circuit, so are best avoided, and we don't need their bogus "mojo" factor.
I was more thinking about metal film resistors than carbon comp ones.

Yes - no problem. They'll work fine. I just built another one this evening for a guitarist friend, and was going to take photographs of it, but he wanted it for a gig tonight, and it's on stage somewhere in London right now, in a plain, unpainted diecast box with hand-written labelling done with a "sharpie"!

wasted_bassist · Post by **wasted_bassist** » 06 Jun 2010, 01:27

I really need to build me one of these. Looking like an all around great compressor. (Psshh, who needs subtle?)

the3secondrule · Post by **the3secondrule** » 03 Jul 2010, 07:56

Hi Mictester -

This was the first compressor I've built - in fact the first I have used as well.

I've noticed with my build that when the compression is turned all the way up, it introduces a nasty distortion in the background. At fist i though it might have been the humbuckers on my Sg overdriving the circuit, but I've noticed the same thing with my Tele. really not sure where to start with debugging this - anything you could recommend?

I used the vero layout, with this photocell:
http://www.smallbearelec.com/Detail.bok?no=711
(#8005)
and these LEDs : http://www.smallbearelec.com/Detail.bok?no=338

any suggestions?

Cheers,

Jeremy

YuGi · Post by **YuGi** » 05 Jul 2010, 09:07

I finished it yesterday, but the sustain pot does not change the sound. I opened the box and saw that the LEDs light up just a little bit and only for a moment (when I bit string). I used two standard 3mm green leds.
Mictester, which is the maximum current that powers the LEDs? I can do tests to see how much current my LEDs needs to light completely.

jgmcd · Post by **jgmcd** » 05 Jul 2010, 17:28

So where can I get the following?

1) a PCB for this effect

and

2) a parts list, preferably with stock/order numbers from Mouser, Digi-key, or Small Bear or other parts house

YuGi · Post by **YuGi** » 06 Jul 2010, 08:55

YuGi wrote:I finished it yesterday, but the sustain pot does not change the sound. I opened the box and saw that the LEDs light up just a little bit and only for a moment (when I bit string). I used two standard 3mm green leds.
Mictester, which is the maximum current that powers the LEDs? I can do tests to see how much current my LEDs needs to light completely.

So I tested my LED and they require 14 mA to fully illuminate. I also tested the LDR, but I found strange values

:
should be 1M in the dark, but completely covered with black tape I see about 200M!

Hides-His-Eyes · Post by **Hides-His-Eyes** » 06 Jul 2010, 13:49

jgmcd wrote:So where can I get the following?

1) a PCB for this effect

and

2) a parts list, preferably with stock/order numbers from Mouser, Digi-key, or Small Bear or other parts house

1) To buy? Nowhere.

2) Nowhere, you can make it yourself and post it if you'd like!

livingnote · Post by **livingnote** » 07 Jul 2010, 11:00

I make PCBs from picture data for a living - you can have anything etched
here that peeps are ok with (mine included of course).

Ben N · Post by **Ben N** » 07 Jul 2010, 15:21

Jeremy, just slightly OT: Your sig needs fixing, if I am not mistaken. "Dude" should be capitalized.

the3secondrule · Post by **the3secondrule** » 08 Jul 2010, 05:35

Ben N wrote:Jeremy, just slightly OT: Your sig needs fixing, if I am not mistaken. "Dude" should be capitalized.

The Dude abides

ppluis0 · Post by **ppluis0** » 15 Jul 2010, 21:19

mictester wrote:
Perhaps what would be interesting would be to branch off the output of the LED driver to something high-
impedance like ?maybe? a Mosfet so that you can get a kindofa "looking glass" LED on the front panel to
see what's going on inside the vactrol. You can get kinda deceived by the "transparent" action of the box,
and that would give you more of a feel for the actual circuit behavior.

Funny you should suggest that - it's exactly what I did to one at the weekend! I'll post the amendment to the schematic for the "optional indicator" here later - it's just a scribble on a piece of paper at the moment. I'll draw it up properly so that it's easy to read.

Hello mictester,

Have you a schem of these option ?

I'm new in this forum, and this will be my first project to be assembled.

Cheers,
Jose

curtisl · Post by **curtisl** » 19 Jul 2010, 16:14

Could I use a 1- Silonex NSL-32 instead of the LDR and 2 leds or does this need 2 leds to work?
Thanks
Curtisl

YuGi · Post by **YuGi** » 19 Jul 2010, 17:13

curtisl wrote:Could I use a 1- Silonex NSL-32 instead of the LDR and 2 leds or does this need 2 leds to work?
Thanks
Curtisl

If I'm not wrong the NSL-32 is 500k dark, this project needs 1M LDR.

curtisl · Post by **curtisl** » 19 Jul 2010, 18:58

My bad, I meant NSL-32sr2.
Curtisl

mictester · Post by **mictester** » 19 Jul 2010, 19:02

YuGi wrote:
curtisl wrote:Could I use a 1- Silonex NSL-32 instead of the LDR and 2 leds or does this need 2 leds to work?
Thanks
Curtisl
If I'm not wrong the NSL-32 is 500k dark, this project needs 1M LDR.

You're not wrong, but it will work, though you might have to change one or two other component values. Remember - the values I give are intended to be a known good starting point. You're welcome to experiment with values, and if you come up with a better combination, please let us all know, and put it up here!

meffcio · Post by **meffcio** » 08 Dec 2010, 16:12

Anyone to PDF the newest layout?

Post by **modman** » 13 Dec 2010, 15:12

Did anyone built this yet? Is the layout confirmed by experience?

mictester · Post by **mictester** » 13 Dec 2010, 15:37

Yes. I built a batch of 5 of them about 6 years ago. I know of two of them that are in constant use to this day.

I've also built several on Veroboard (including the one for myself).

Really Cheap Compressor [documentation]