Browne Amplification Protein Green channel

[dutcheffects]

Dear all,

just new to this forum but have been building effects since 2012. I'm running into some trouble building the browne amplification protein on tagboard. Blue channel works great, http://dirtboxlayouts.blogspot.com/2023/02/browne-amplification-protein-blue.html.

But the green channel sounds really dark and wooly, http://dirtboxlayouts.blogspot.com/2023/02/browne-amplification-protein-green.html.
Used a j201 and 2n5088, IC's are NJM4558. Diodes 1n4148 and 1n5817. Been through al the traces and components and they are all correct. Also measured all resistences and caps and are all within range.

Learned about the two frequency cuts 1.5K with 2.2uf and 820ohm with 82nf. Played around with 50k bass mod which just cuts the bass, but doesnt open up the sound.

Could it be the transistors? What are your ideas? 

[duck_arse]

welcome to the forum.

please post a circuit diagram. then take voltage measures of IC's and transistors, supply and bias voltages. then take some photos of what you have built, component side, solder side, and all the offboard stuff. these are the rules.

[stonerbox]

Happily try to help you but we/I need schematics of both circuits first. Just to get a grasp of what you like about the Blue and not so much with the Green and what could be suggested to improve on the latter one. My guess would be smaller coupling capacitors here and there or some radical adjustments to the tone stack in the Green.

One more thing, what guitar are you testing it with?


Edit: Yeah, checked some videos and the green channel is muddy as puddle of barf. Sounds like it low passes around 3-4kHz.

[stonerbox]

Dug up the schematic.

[click for full size]

[dutcheffects]

You guys are great. Sorry for not sending the schematics. Will Post some photos of my build in a couple of hours. Foirst one is the green channel, second the blue.

[dutcheffects]

I have tried the pedal with a Les Paul Standard 60s, Gibson sg special with mini humbuckers, fender telecaster and stratocaster. My amp is a morgan pr12, princeton reverb like with a bigger power supply.

Will Post some photos and voltages later on.

[dutcheffects]

Here are two pictures of the tagboard and backside. It's a a bit of a mess but haven't taken the time to desolder everything. Left on top is the green right the blue. At the back it's the other way around. The pot with two orange leads on the back is a 50k bass pot between 1.5k resistor and 2.2uf cap. Black wire is connected ground between the two boards.

[Rob Strand]

Could it be the transistors? What are your ideas? 

Try increasing the 5.1k resistor (R23 on the schematics) to say 10k and see if that pushes the sound closer to what you want.  Nothing stopping you trying larger values.

That's of course assuming you don't have a build problem like a short, wrong connections or even a wrong resistor/cap value (anywhere in the ckt).

[dutcheffects]

Voltages of Ic's Transistors and supply

IC 1
1: 2.954v
2: 2.954v
3: 2.950v
4: 0v

5: 2.940v
6: 2.958v
7: 2.962v
8: 8.94v

IC 2
1: 2.956v
2: 2.956v
3: 2.916v
4: 0v

5: 2.962v
6: 2.965v
7: 2.964v
8: 8.94v

Q1: J201
D: 8.94v
S: 0.565v
G: 0v

Q2:2n5088
C: 8.94v
B: 2.716v
E: 2.140v

Supply volttage = 9.20v

[ElectricDruid]

2.9V looks a bit low for the Vref voltage, unless your meter is really loading it. We're expecting 4.5V. From the photos, the resistors look right - 2 x 15K are *visible*, at least!

[duck_arse]

observe your diodes. out by one. also, please pull your IC's out of their sockets. check the wipes of the sockets, and the legs of the IC's. please.

what does the Vref measure AT Vref?

[dutcheffects]

Duck_arse, you are the man!. How could I be so blind. after switching the diodes to their correct position voltage at VRef was 4.49v. Also at pin 1,2,3,5,6, and 7 of IC 1 and 2. The sound is actually kinda very cool right now. Gonna play around with some other transistors. But this was the fault. Thank you all so much for your mega fast replies and advice. I'm very happy. I will post some pics when its finished

[dutcheffects]

Very happy with this one!