Weak Joe compressor

[nosamiam]

I'm needing a compressor that is very tweakable.  I plan on using it mostly for live bass (if I like it in that application) and definitely for tracking bass and vocals.  I was looking at the Weak Joe.  It seems to be one of the only DIY projects out there with adjustable attack/release that is available online with PCB, component layout, etc.

My question is, has anyone built it?  Successes? Failures?  Anything I should look out for?

I don't really want to breadboard it since it's a relatively complex circuit, especially if I'm pretty sure it's gonna work with minimal fuss as-is.  But I obviously don't want to go to the expense if I won't be able to get it to work.  My troubleshooting skills are coming along pretty well, but that said, I have had a couple of unsuccessful builds and I don't want to add this one to my list.

Any input?

Thanks!

[nosamiam]

Oh yeah... here's the link:

http://www.geocities.com/m_natsume/what_compressor.html

[nosamiam]

No replies?.....

Alright then, I'll just forge ahead.  Maybe I'll do my first build report when it's done.  If it works.  If not, I'm sure I'll be asking for help.

Thanks!!

[jlullo]

hey!  if you wanted to do a version of the ross/dyna comp, you could do the mods listed here:
http://fuzzcentral.ssguitar.com/ross.php

specifically the variable attack/recovery mod.

not sure how helpful this would be for vocals, etc, but this is a nice sounding circuit and i think there's a bunch of cool mods you could do.

[petemoore]

  Looks like Weak Joe is good coffee to me. LA 2 compressor type that uses a photocell, should work, haven't remembered reading...and didn't really read that much on it, if it looks like it does what you want..
  I guess you want a tweekable compression, 'specifically the variable attack/recovery mod'^.
  
  I took a better look at Joe, seems they've got him pretty well sorted out, I can't verify, but, would bet it works as shown. He has alot of knobs, making say three of them fixed tweeks, then just have compression amount and volume control..could be all you need or want for the actual job it's intended for. Kind of nice in a way to have one with all the bells and whistles to sort out which ones you need to have instantaneously adjustable, otoh, that can be alot of knob turning and intense listening to sort out too, it might theoretically be easier to start with more of the parameters fixed, test try it for a time or two, then decide what you'd like it to do more or less of, then do value adjustments or component swaps for that tweek.
  Comps are nice to have around, maybe just try two different ones!
  Dyna can be made to hard compress, mods available.
  Photo comps are easier for me to look at a schematic and sort out what's going on.

[Bassmanfox]

I just finished a 4 channel weak joe.  As of now its the only "studio" compressor I have.  I went for the weak joe found here http://www.geocities.com/m_natsume/what_compressor.html because of its tweakability so I could use it with all different types of instruments. 

I used all polyfilm caps, metal film resistors, ne5532's and I used the exact layout on the site.  I used a  +-15 toriodial transformer from parts express http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=122-605 along with a pretty standard power supply setup.  Its quiet and adds no real noise even with high gain settings.  Its great for vocals, just like the original what compressor.  I think its nice for the bass as well.  It serves well as an all around workhorse compressor.  Its only fall back is that at high compression it seems to be hard to get it not pumping and breathing.  I've had troubles with it distorting, but with screaming mic'd guitars and drums at higher compression settings.  I can also work as a limiter, but I haven't used it as such much.

  I've also built the orange squeezer pedal and the La-2 aka fat n pretty found here http://moosapotamus.net/THINGS/fatNpretty.htm .  The orange squeezer is nice, but only for guitar and the La-2 is a bit of a wild thing and wasn't too fun to set up and get a usuable sound out of.  I think you could get the weak joe  going easily. 3 out of my 4 worked right away with minimal tweaking of the trim potr.  The other one just was a weird trace error that took a little bit to find.  One tip, I suggest using the sites layout is well worth it because its completely noiseless and I think thats due too the ground plane.  I was able to make 2 seperate boards, one top layer, one bottom and then just drill out the op amps very carefully on both then I soldered the op amps in and it lined both up.  I then drilled some mounting holes and placed screws in for more support and then drilled out all the holes so they'd match up perfect, well close to perfect.  Its a little basement engineering, but it works.  If you have any other questions feel free to ask.

[nosamiam]

A ha! I just didn't wait long enough for the replies to show up!  I should have known someone would come through!!

Thanks for all the tips!

Bassmanfox:  How did you mount that transformer?  It looks like just what I need.  And thanks for the 2-board hint.

Petemoore:  Thanks for the ideas about fixed resistors.  I hadn't really thought about it.  I may do it.  I'll try to see if I can find any setting I like for all uses.

Alright, I'm off!

[Bassmanfox]

The transformer itself comes with nuts, bolts and a washer so you can mount it anyway you wish.  I mounted the whole thing, all 4 compressors, trans, and psu, in one 3u 19" wide X 14" deep, rack with no room issues.  I think you maybe able to find a bigger hammond box or something similar and mount 1 or 2 in there.  I'd like to know where the author got his case for his 2 channel version, seems really portable. 
You may want to look into a pre amp too.  I built a 4 channel green pre too that goes along great with the weak joe.  Depending on your wants and needs that maybe a great all in one unit for the studio and live.

[nosamiam]

Thanks Bassmanfox.  That wasn't apparent from the pics on the site.  The last project was an 8-output power supply.  I used the Weber 9 output transformer and it didn't come with any mounting provisions.  I ended up having to be pretty creative but it worked out fine.  I really don't want to have to try that hard again, so I'm glad it comes with its own stuff.

I'm glad you think it'll fit in a Hammond or similar box.  I'm wanting to put it on my pedalboard and I'm only doing a mono unit, so looks like it'll be possible.  Thanks for the help.

[Bassmanfox]

I've been meaning to post a build report on this for a while....

I built this compressor for studio use.  I built 4 of them into a rack mount enclosure.  I built them to the exact specs/schematic/layout found here: http://www.geocities.com/m_natsume/what_compressor.html.  Please note, to get the layout the correct size, use the print preview button on mozilla and size to a custom 58%.  I used the stereo option to link channels 1 and 2 together.  I mainly use this feature for drum overheads.

I think this is a quite a versatile compressor for live and studio applications.  To me it works better than the standard dbx compressors.  If you read into it, the weak joe was a response to the alesis 3630, which I'm pretty sure is just a re-branded dbx thing. I think the weak joe has got a nice slight color thats only makes sound warmer and "closer/tighter".  Before the weak joe I used the S-com 4 by samson, which all and all is beginner cool unit, but its slightly noisy and its "auto" compression is nice, but I'm just not that lazy, I like to know what actually is being dialed in.

The only draw back to the weak joe is the LED display is only one LED.   There is a link somewhere  on how to add a multi-LED display, I'm just fine with my ears and the one LED.  I think you'll find that link, plus countless other projects and good info on http://www.prodigy-pro.com/  I do suggest the weak joe over most any compressor build as it seems the most versatile for the money and simplicity.

I used all wima polyfilm caps, metal film resistors, ne5532's.  I used a  +-15 toriodial transformer from parts express http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=122-605 along with a pretty standard power supply setup.  Its quiet and adds no real noise even with high gain settings.  Its terrific for vocals, just like the original what compressor.  I think its nice for the bass as well.  It serves well as an all around workhorse compressor.  Its only fall back is that at high compression it seems to be hard to get it not pumping and breathing.  I've had troubles with it distorting, but with screaming mic'd guitars and drums at higher compression settings.  I can also work as a limiter, but I haven't used it as such much.

As for a PSU, I made my own, but there are many on the web and they are all really the same, mine was similar this one found here http://1176neve.tripod.com/id26.html, but without the 48v section, meaning with out d2, d3, d4, c11, c12, c13, u3 and the components after it.  Just make sure you buy heat sinks for the lm317 and lm337 as they get hot when you run even one channel.  There is one here http://sound.westhost.com/project05.htm its a little beefier, but works too.   

If you plan on building more than one I suggest buying nearly twice as my VTL5C9's and matching them all, probably 1 out of 4, has a pretty significant spec difference from the others.  I planned on doing a 4 channel, so I bought 8, 6 out of my 8 were the same, so yeah I was left with a few, but if you are DIYer you'll find a use.  How I match them was simple, I took 2 resistors one 20K and one 220K.  Then connected exactly 9v to the one end of a resistor and then the other end to the + on the vactrol, I then placed ground of the power supply on the -(neg) of the vactrol.  Give it about 30 seconds to settle and measure the resistance of the other 2 leads.  Do this once for the 20k and once for the 220k.  Then just match the ones with similar values.  I highly suggest doing this, especially if you plan on pairing 2 up and using the stereo option.

Now the question is, is this worth it to make this in a stomp box format?  I think yes, but you can make it a lot simpler.  It could be used for guitar, bass or vocals. I think you could rid yourself of the attack and release controls.  If you planned on using it for guitar, a 1k resistor in place of the attack and around 330k for the release would be good starting points.  If available your best bet would be trim-pots and then dial it in till you get what you are looking for.   As for voltage, I think it would have to stay at +-15, I dunno if it could work as well at +-9.  You could implement the same idea moosapotamus used for the LA-2(found here: http://moosapotamus.net/THINGS/fatNpretty.htm)  Using a NMH0515S(found here: http://www.mouser.com/search/ProductDetail.aspx?R=NMH0515SCvirtualkey58010000virtualkey580-NMH0515SC) and get your +-15.  Its a little expensive of a route, but all and all its worth it for the space this would save. I check the dimensions and with any luck you could squeeze it all into a LMB heeger case, mouser pn# 537-MDC642-01.  These are get sturdy little boxes.  I use these cases for all my more complex circuits as they have a lot of room and make nice neat routing very easy.

  Yeah so all in all I think its well worth it.  Time spent to do all 4 was around 2 -3 full 8 hour days, this includes everything, enclosure drilling and manufacturing of the boards.  The boards themselves are low parts counts and don't take much time at all.  I think the final price came out to around $150 with everything for4, which is what you'd pay for most lower grade 2 channel units.  I'd say if I were to sell this guy I'd have to charge around $125-$150 a channel.

[chillhuman]

After looking @ the pcb layouts from the weak joe site, I have one small question - did you have to mirror the ground plane before burning your pcb's ? It looks like without doing this, you will have to manage an iron in between the 2 boards to get the holes to match up. Is this correct or am I crazy ?

[Bassmanfox]

yeah if you want to do the the layout the way I explained you have to flip one of the layers.  Just open it up in ms paint or what have ya and flip it horizontal.  I dunno if you are confused either, but when ironing out the layout make sure to do each layer separately on separate pieces of copper. 

[nosamiam]

Thanks for the latest posts, Bassmanfox!  I haven't started yet.  Decided to hold off for a little bit in order to work on some other projects I'm just getting around to.  The Weak Foe's coming up though!

[markm]

I've never tried this....EVER!......but, what about using double sided board to etch the pcb?