Coda Effects Black Hole

[selfdestroyer]

Damn your on a roll this month!

Great job

[Hexjibber]

Damn your on a roll this month!

Great job

Cheers Cody! 

[benny_profane]

I keep coming back to this build. Such a fantastic job with the finish!

I was looking at the schematic and had a question:
Q4 before the tonestack is a common drain amplifier. I'm not terribly familiar with the biasing here. There's no gain resistor and there's a static source resistor. If the circuit were to be adapted to run at 18v, how would that biasing need to be changed?

[SirEgno]

Looking at the original schematic the 4th triode is (I don't know the correct word here... biased?) at the same way. 100k resistor on the cathode. maybe it's a coincidence...
My question is about the "anode" trimmers. is 20k enough? I've alway seen 100k trimmers on fet drain.

Now the real important thing. This build is awesome! The graphic gives a 3d look at the pedal.

[diablochris6]

Love that enclosure design/paint job! It's insane that you got such ripping tones without the transistors soldered in...

[Hexjibber]

Love that enclosure design/paint job! It's insane that you got such ripping tones without the transistors soldered in...

Haha! I managed to get these super rare invisible ones, to say they have the mojo factor would be an understatement! Very hard to come by owing to the fact you can't see them, getting the orientation right was tricky to say the least!


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[Hexjibber]

Now the real important thing. This build is awesome! The graphic gives a 3d look at the pedal.

Thanks!


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[Hexjibber]

If the circuit were to be adapted to run at 18v, how would that biasing need to be changed?

I have to confess I have not even the slightest idea! Maybe a question for Benoit over at Coda Effects?


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[benny_profane]

If the circuit were to be adapted to run at 18v, how would that biasing need to be changed?

I have to confess I have not even the slightest idea! Maybe a question for Benoit over at Coda Effects?


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I remember asking awhile back and he said to just be sure the caps were rated accordingly. The other JFETs have bias trimmers, so no problem there—just a little outta depth with the common drain biasing.

[jazzster]

Hello. I am currently working on a Black Hole build and I am having an issue.

The main part of the pedal works perfectly but the issue I'm having is that the boost section is not working. I have it wired to a 3PDT footswitch as well as an LED. I also turned the 100k boost trimpot into an external pot with a knob. When I hit the footswitch for boost, the LED turns on but all sound cuts out. The other weird thing is that as I turn up the 100k pot the LED will dim.

If you have any ideas on what may be wrong I would really appreciate it. Cheers.

[m-Kresol]

Hello. I am currently working on a Black Hole build and I am having an issue.

The main part of the pedal works perfectly but the issue I'm having is that the boost section is not working. I have it wired to a 3PDT footswitch as well as an LED. I also turned the 100k boost trimpot into an external pot with a knob. When I hit the footswitch for boost, the LED turns on but all sound cuts out. The other weird thing is that as I turn up the 100k pot the LED will dim.

If you have any ideas on what may be wrong I would really appreciate it. Cheers.

Hi Jazzter,

sounds like a wiring issue with your 3pdt. from your description it sounds like you may have grounded your out- or input. the fact that the led is interactive with the pot suggests that you're loosing supply voltage somehow

I'd suggest you open a tech-help thread with clear pictures of your build and a few details. If you follow the guidelines in the tech-help section you'll likely find the culprit already. If not, we'll try to help for sure.

[jazzster]

Ok sounds good. I put everything into the Tech Help page. Very new to the forum thing.

[jazzster]

SOLVED. Matmosphere helped me out. I just had my boost switch wired incorrectly.