What is a good compressor pedal to build off of?

[mdeffects]

Hey everyone!

This is my first time posting here, so forgive me if I don't get it right! Anyways, I've been wanting to build a compressor for some time now, and I didn't want to just make a clone of something, I want to make it my own. So I'm wondering what is a good compressor schematic to go off of for creating a custom designed compressor? Ideally one that has room to have a dramatic compressed sound. I really love that really squished punchy compressor sound. Also low part count would be great too! Thanks in advance for all the answers!

- Matthew

[merlinb]

Say no more:
http://valvewizard.co.uk/engineersthumb.html
http://www.diystompboxes.com/smfforum/index.php?topic=97123.0

[Kipper4]

Excellant choice MB

[R.G.]

As an alternative, you might look at the SSM2166. This is a single chip that has been designed from the ground up to be a studio-quality compressor, and includes variable compression, variable thresholds, noise gating, and limiting as well as a programmable 0db to 20db front end gain/buffer.

http://www.mouser.com/ds/2/609/SSM2166-879640.pdf

I've used this several times, and it's quiet, straightforward and well behaved. The chips are about $6-7, in stock at Mouser.

[Transmogrifox]

If wanting to "make it your own" and really learn something while you do it, the Engineer's thumb is going to be a good bet.  Follow the forum thread linked by merlinb and read up on the problems it solves and you will see it is a good basic building block for a nice sounding guitar-oriented compressor.  You could convert it to a feedback compressor if you like the squish that comes from the continually-increasing ratio that comes from the feedback topology.  You might also add a noise gate (downward expansion) function.

Another possibility if you are looking for a feed-forward compressor is RANE DC22S:
http://www.rane.com/pdf/old/dc22ssch09.pdf
Extract one of the compressor channels from that one and adapt it to a 9V power rail (or just keep the +/-15V)-- it uses the THAT corporation VCA and RMS detector IC's
Might browse other RANE discontinued products for other compressor implementations -- they have had quite a lot over the years which can give you some good ideas.

I also have a compressor I built based on the SSM2166 -- all of what RG stated is correct.   It's really convenient having the downward expansion function built-in. The only downside from the perspective of wanting something "to be your own" is that the 2166 is pretty much a canned solution.  I really didn't feel much more satisfied with that build than I would have from assembling a kit.

[mdeffects]

Say no more:
http://valvewizard.co.uk/engineersthumb.html
http://www.diystompboxes.com/smfforum/index.php?topic=97123.0

Thanks! I'll definetly look into this!

As an alternative, you might look at the SSM2166. This is a single chip that has been designed from the ground up to be a studio-quality compressor, and includes variable compression, variable thresholds, noise gating, and limiting as well as a programmable 0db to 20db front end gain/buffer.

http://www.mouser.com/ds/2/609/SSM2166-879640.pdf

I've used this several times, and it's quiet, straightforward and well behaved. The chips are about $6-7, in stock at Mouser.

How exactly would I apply this? It sounds very simple to use, and would keep my design witha very low part count, which is ideal for me! If you have any tips to exactly how this looks, it would be much appreciated!

If wanting to "make it your own" and really learn something while you do it, the Engineer's thumb is going to be a good bet.  Follow the forum thread linked by merlinb and read up on the problems it solves and you will see it is a good basic building block for a nice sounding guitar-oriented compressor.  You could convert it to a feedback compressor if you like the squish that comes from the continually-increasing ratio that comes from the feedback topology.  You might also add a noise gate (downward expansion) function.

Another possibility if you are looking for a feed-forward compressor is RANE DC22S:
http://www.rane.com/pdf/old/dc22ssch09.pdf
Extract one of the compressor channels from that one and adapt it to a 9V power rail (or just keep the +/-15V)-- it uses the THAT corporation VCA and RMS detector IC's
Might browse other RANE discontinued products for other compressor implementations -- they have had quite a lot over the years which can give you some good ideas.

I also have a compressor I built based on the SSM2166 -- all of what RG stated is correct.   It's really convenient having the downward expansion function built-in. The only downside from the perspective of wanting something "to be your own" is that the 2166 is pretty much a canned solution.  I really didn't feel much more satisfied with that build than I would have from assembling a kit.

So if I understand the SSM2166 diagram that RG linked, it's just showing where/how each pin connects? Are those resistor and capacitor values able to be tweaked at all? If you have any pictures/diagrams of what you did for your project I would love to see!

[blackieNYC]

http://www.muzique.com/tech/2166.htm
Jack Orman has a schematic that I believe is little more then the data sheet. Which is probably for consumer or maybe pro audio.
I've been putting off a showdown between these two (ET vs Q&D) for a year.  Must build first.

[mdeffects]

http://www.muzique.com/tech/2166.htm
Jack Orman has a schematic that I believe is little more then the data sheet. Which is probably for consumer or maybe pro audio.
I've been putting off a showdown between these two (ET vs Q&D) for a year.  Must build first.

Thanks so much blackieNYC I really appreciate it. I will look into this and see how I can mod it or maybe change it a little bit.

[LightSoundGeometry]

Hey everyone!

This is my first time posting here, so forgive me if I don't get it right! Anyways, I've been wanting to build a compressor for some time now, and I didn't want to just make a clone of something, I want to make it my own. So I'm wondering what is a good compressor schematic to go off of for creating a custom designed compressor? Ideally one that has room to have a dramatic compressed sound. I really love that really squished punchy compressor sound. Also low part count would be great too! Thanks in advance for all the answers!

- Matthew

hey MD! I thought I recognized the name. you are definitely in the right place

[R.G.]

So if I understand the SSM2166 diagram that RG linked, it's just showing where/how each pin connects? Are those resistor and capacitor values able to be tweaked at all?

Actually that datasheet has a fairly long rundown on the nominal application circuit and if you search for SSM2166, you come up with Analog Devices' application note that spells out how to apply it in fairly large detail, including what to tweak for various compression ratios, turnover points, gating, all that.

[mdeffects]

Hey everyone!

This is my first time posting here, so forgive me if I don't get it right! Anyways, I've been wanting to build a compressor for some time now, and I didn't want to just make a clone of something, I want to make it my own. So I'm wondering what is a good compressor schematic to go off of for creating a custom designed compressor? Ideally one that has room to have a dramatic compressed sound. I really love that really squished punchy compressor sound. Also low part count would be great too! Thanks in advance for all the answers!

- Matthew

hey MD! I thought I recognized the name. you are definitely in the right place

Hey Jon! Good to see you here too!

So if I understand the SSM2166 diagram that RG linked, it's just showing where/how each pin connects? Are those resistor and capacitor values able to be tweaked at all?

Actually that datasheet has a fairly long rundown on the nominal application circuit and if you search for SSM2166, you come up with Analog Devices' application note that spells out how to apply it in fairly large detail, including what to tweak for various compression ratios, turnover points, gating, all that.

Yeah, I see that now. I guess I know what I will be reading the next few days! Thanks so much!

[Transmogrifox]

So if I understand the SSM2166 diagram that RG linked, it's just showing where/how each pin connects? Are those resistor and capacitor values able to be tweaked at all? If you have any pictures/diagrams of what you did for your project I would love to see!

The short answer is yes, you can mess with resistor values and even connect pots instead of resistors.

If designing from the datasheet is a bit much for you to bite off at this point then the link provided to amz Q&D compressor is a good design based on the SSM2166, and it exposes all of the useful functions to the user with pots.

Here are some pictures of my SSM2166 compressor.  I don't think I have schematics any more, or if I do it's hiding in stacks of old notebooks from various things I have tried over the years.   Would take me less time to re-design it than to find that stuff

With the AMZ comp at your disposal I don't think whatever is in my design gives you any benefit whatsoever, but the pics may be interesting to you.  This was designed and built 12 or 13 years ago as part of a EE senior design project.  This was the time in my life when making things more complicated than they had to be was cool.  I think the AMZ comp will serve you much better than to copy mine.

Jack Orman is well-seasoned and probably long past having any notions that over-complicating things is cool, so his designs are good learning and copying material.

[mdeffects]

So if I understand the SSM2166 diagram that RG linked, it's just showing where/how each pin connects? Are those resistor and capacitor values able to be tweaked at all? If you have any pictures/diagrams of what you did for your project I would love to see!

The short answer is yes, you can mess with resistor values and even connect pots instead of resistors.

If designing from the datasheet is a bit much for you to bite off at this point then the link provided to amz Q&D compressor is a good design based on the SSM2166, and it exposes all of the useful functions to the user with pots.

Here are some pictures of my SSM2166 compressor.  I don't think I have schematics any more, or if I do it's hiding in stacks of old notebooks from various things I have tried over the years.   Would take me less time to re-design it than to find that stuff

With the AMZ comp at your disposal I don't think whatever is in my design gives you any benefit whatsoever, but the pics may be interesting to you.  This was designed and built 12 or 13 years ago as part of a EE senior design project.  This was the time in my life when making things more complicated than they had to be was cool.  I think the AMZ comp will serve you much better than to copy mine.

Jack Orman is well-seasoned and probably long past having any notions that over-complicating things is cool, so his designs are good learning and copying material.

Thanks so much for the pictures and info! It looks great! I think I will look into both the datasheet and the amz article. Also, one more question, does anyone know of a way I can solder the SSM2166 without any special tools? I just have a typical soldering iron.

[balkanizeyou]

in my country it's still possible to buy the ssm2166 chip in DIP package (I believe it was discontinued), but if you can't find it, then soldering SOIC chips with a cheapo chinese soldering iron ain't that hard either.
Just google any SMD soldering tutorial and use a desoldering braid if you get any solder bridges.

[bluebunny]

Another vote here for Merlin's "Thumb".  But also take a look at Jon's Bear Hug design.

[Cozybuilder]

Check out Sam Hays' "Light Speed Compressor"

http://www.diystompboxes.com/smfforum/index.php?topic=113668.msg1054692#msg1054692

[mdeffects]

All of the articles/videos I have seen show them using flux, is that a need? I would just love not to have to buy another product.

[balkanizeyou]

you can easily solder SOIC packages without flux, although I'd advise you to buy it, because you will need it at some point either way.

[Transmogrifox]

+1.  I built the prototype in my photos without the use of flux.  There's a close-up of the SOIC solder job to see what you get from it.

Also I rarely waste my time with flux on an SOIC or larger at work  (it is a bit of a mess).  Often don't use it on 0402 SMT resistors.  I will usually find the flux if working on something like a TSSOP package.

I recommend a small (<1mm wide) chisel tip for this job.  Pencil tip will work, but it doesn't spread the heat evenly along the trace and up the lead.  Usually I place 1/2 the tip on the lead and 1/2 on the trace and then lightly tap the trace with solder.

Also +1 on buying some flux eventually.  It's particularly useful when soldering to pad-per-hole perfboard or onto un-tinned PCB (like if you do a DIY PCB).  Also if you're ever doing a pedal professionally (for sale) using flux will help you do a much neater job and avoid wasting your time with soldering-related troubleshooting.

[mdeffects]

Alright thanks for all the help guys! Look like I've got some shopping to do!