Bearhug Compressor - schematic, demo, layouts, & forthcoming 1776 PCB!

[pba]

Jon, сompare the polarity of C6 (10mf) on the schematic and layout )))

[midwayfair]

Jon, сompare the polarity of C6 (10mf) on the schematic and layout )))

Yeah, it's backwards on the layout. I'm just being lazy and haven't fixed it. Thanks for the reminder.

[pba]

Jon, do you like )))

[midwayfair]

Looks like it will be going in a

Bear enclosure.

[pba]

corrected...

[pba]

Jon, today launched your project. Everything works fine, but there is one thing))) ... It would not hurt, rotated Q1 and Q3 to 180 degrees on the layout. 
I compared with Ross/Dyna and Demeter Compulator... The sound very similar Compulator (without losing of high freq.)
Thanks Jon!

P.S. Sorry for the google translator.

[midwayfair]

Jon, today launched your project. Everything works fine, but there is one thing))) ... It would not hurt, rotated Q1 and Q3 to 180 degrees on the layout. 
I compared with Ross/Dyna and Demeter Compulator... The sound very similar Compulator (without losing of high freq.)
Thanks Jon!

P.S. Sorry for the google translator.

Thanks for catching the mistakes in the layout -- I've updated the layout.

[pba]

Another little thing ... Contacts 1 and 3 of pots (on the layout) must also be rotated 180 degrees

[midwayfair]

Another little thing ... Contacts 1 and 3 of pots (on the layout) must also be rotated 180 degrees

They're numbered correctly in the layout (there are numbers on the pads to be connected). I standardize my layouts to have the pots on the right side numbered 1-2-3 from the top.

[pba]

Well then, no more problems. I just got used to such designations:

[Cozybuilder]

Mine sounds real good! I tried the B1K comp pot but as you noted it bunches, the C1K is the way to go. Had to use a 16mm for that, which led to 16mm for the volume as well, and presented a whole set of difficulties to overcome. Well worth the effort- this build uses ¼ watt metal film resistors, Neutrik ¼" jacks, low-profile DPDT stomp switch, Millennium bypass, bicolor LED- green for on, red for compression, and SPDT on-off-on with two 220K resistors for slow, normal, and fast decay options as suggested by Jon. All in all, a difficult but very satisfying build.

Test run- success!


Circuit card back side


In-process, almost there


Side view- in process


In-process component layout

[midwayfair]

THAT'S.

INSANE.

[bluebunny]

 

@Russ: someone put your compressor through a compressor!  I feel claustrophobic looking at those gut shots.   

[duck_arse]

I couldn't even collect the loose parts into a space that small. I like the custom shaped board.

is it yellow for compressors?

[Cozybuilder]

DA- Yes, compressors get Fluorescent Yellow (maybe I should have made them red though)
Here are a couple of clearer shots:

Completed face (I need a smaller washer for the toggle)


Gut shot and layout. The second ground from the 9V jack goes to the pots and out jack. For the sharp eyed, Q5 spot is using a 2N3904 in the build.


Circuit card back side


Component layout


Side view in-process


I arranged photobucket images into folders- didn't expect them to come up as "removed"- sorry

[duck_arse]

I haven't even seen them, and they alread show as:

[midwayfair]

I forgot to update this thread when the new version of the PCB was released. It has some changes to the caps for better frequency control and the bias voltage for the gate is trimable. Link in my sig -- josh redrew the schematic for me and I can't update the op.

[chuckd666]

Hey Jon!

Thanks for your ongoing support with this ol' thing.

I have an issue with my build. I am using the PCB layout found here - http://effectslayouts.blogspot.com.au/2015/07/bearhug-fet-compressor.html

My transfer was fairly successful and all traces are intact.

I am getting little compression but lots of boost. I am also getting distortion. It's almost more like a warm low gain drive pedal at the moment (with that BS170 chubby feel).

My voltages from 9.38V supply are as follows:

Q1
D 4.72 (seems to be dropping slowly, but continually every time i check it)
G0.36
S 1.97

Q2
C 7.54
B 0.56
E 0.026

Q3
D 0
S 0
G 0

I have checked for resistance between legs of the 2n5457 and getting 844ohms.

I just realised that my 2n5457 is the wrong way around... but when it's the RIGHT way around it's giving below unity when full volume (and negligible compression). When it's the wrong way around it's boosty as hell, but again with little compression.

Any thoughts? I'm bloody stumped. Cheers!

Charles

[midwayfair]

Measure the resistance across the FET when playing a chord and see if you get a resistance increase. But 844 is extremely high for a 2N5457; I rarely see anything outside 300-500 ohms. So something else might be wrong.

Your Q1 gate is also crazy low. It should be above 4V at least.

[chuckd666]

Crikey. Thanks for the tips. Will report back once I have time to sit at my workbench.

Thanks Jon!