Before the Holidays I grabbed a used EQD Bellows off eBay. Great sounding dirt box on both guitar and bass, plus soft touch relay switching. Of course before I even plugged it in I cracked it open and took a peak in side. Not too long after I was able to trace it (ignoring the PIC-based relay bypass circuitry). Here's the schematic:
(http://guitar-fx-layouts.42897.x6.nabble.com/file/n35425/EQD_Bellow_schem.png;cid=1473944509994-734)
The JFET threw me, so I breadboarded it real quick (with a J201 for the JFET) and it fired right up. I made a layout for my blog and went ahead and built it up on perf to verify it. With the original being in a 125B enclosure, I went ahead and boxed it up in a 1590B with top mounted jacks (or TMJs as Cody and I call them). Smaller footprint FTW. Wasn't feeling all that inspired for graphics, so I just spray painted it orange and painted some flames on there.
(https://s27.postimg.org/905ih7fmr/IMG_5407.jpg)
(https://s29.postimg.org/62s7bhupj/IMG_5408.jpg)
(https://s29.postimg.org/btifiy46f/IMG_5409.jpg)
For bypass I used good ol' Millenium 2 bypassing with a DPDT (I have a bunch of those lying around).
Tidy build. Even though you were not inspired, the flames came out looking good!
That's a really clean spray paint job! I have never been able to get top mounted jacks to work in a 1590b. Thanks your work on the blog, I use it a lot. Do you know what the jfet is doing to the circuit?
cool build. I like how it looks like a chemical safety sign :)
Do you have a template for TMJs in a 1590B? I ask because for some reason my work firewall is blocking pictures today so I can't see how it's laid out. :(
Looks excellent.
That's an insane sounding pedal.
Sent from my iPhone using Tapatalk
That circuit is very clever.
That came out great David. I really like the simplicity of the artwork and the knobs.. and I am always a sucker for TMJs lol.
Cody
I was thinking the same thing as Jon. It's a unique way to do dirty boost, and I believe I haven't seen it done that way yet. That's cool, because I'm pretty sure I've seen a dozen other ways, and it's easy to get a little jaded.
Jacob
TMJs FTW!
I like the simple graphics. They look clean and hard to miss on a dark stage.
Quote from: jkokura on January 17, 2017, 08:02:21 PM
I was thinking the same thing as Jon. It's a unique way to do dirty boost, and I believe I haven't seen it done that way yet. That's cool, because I'm pretty sure I've seen a dozen other ways, and it's easy to get a little jaded.
Jacob
I was just looking at the build before I hit your comment. You're right; that is very clever indeed. Very, very cool.
Great build, too! I always enjoy your simple, clean PCB etches; circuit art at its most elemental.
Cool build dude, and as the others have said, that design is new to me and is really interesting...
Time to get the breadboard out!
Quote from: jkokura on January 17, 2017, 08:02:21 PM
I was thinking the same thing as Jon. It's a unique way to do dirty boost, and I believe I haven't seen it done that way yet. That's cool, because I'm pretty sure I've seen a dozen other ways, and it's easy to get a little jaded.
Jacob
I'm going to encourage people to breadboard it and measure the voltage at the drain while playing, then measure the resistance across the drain->source while playing. Or you can ponder JFET switching or the Orange Squeeze to guess what might happen.
It actually has roots in the Bazz Fuss, though you have to squint to see it. The gate and any N junction (FETs are symmetrical) form a diode.
Very nice. Thanks a bunch for doing your layouts. I've made several boards with the info
from your site. This one will go on the list.
Thanks guys! And thanks Jon for the homework/explanation of how the JFET works. I thought I saw some Bazz Fuss in there.
Quote from: sonnyboy27 on January 17, 2017, 06:47:57 PM
Do you have a template for TMJs in a 1590B?
I don't have a template per say. Just some notes written down on my bench. The dimensions I use kinda vary based on the enclosure manufacturer. I'll copy notes and post it here when I get home.
Yeah thanks Jon for that. I gotta try this on a breadboard.
Sorry for getting back to this so late. Got the flu. :-\ Anyway, here's my 1590B TMJ guide.
(http://i756.photobucket.com/albums/xx206/storyboards27/Mobile%20Uploads/41FECF1E-50A2-4CF7-AE71-1D5E812CD67E_zpstbjbtdnt.jpg)
I was feeling like it, so I made a 2 layer pcb for this suitable for 1590a. it's available via oshpark here:
https://oshpark.com/projects/zKa4A1JP
if anyone verifies the layout please let me know.
thanks for tracing storyboardist
Quote from: m-Kresol on January 22, 2017, 02:13:47 PM
I was feeling like it, so I made a 2 layer pcb for this suitable for 1590a. it's available via oshpark here:
https://oshpark.com/projects/zKa4A1JP
if anyone verifies the layout please let me know.
I ordered your board, verified!
(https://i653.photobucket.com/albums/uu259/Erdnuessemitchili/IMG_20190712_192608_zpsfezpnvvj.jpg)
(https://i653.photobucket.com/albums/uu259/Erdnuessemitchili/IMG_20190712_190210_zpsucmm8cxj.jpg)
nice! thanks for verifying and sharing your build. great work!