OCD/ADHD Toans

[DeadAirMD]

Just built the ADHD, absolutely love it. I'm wondering though if I did something wrong. I wanted to build the germanium version. But, when I take out the germanium diodes, there is literally no change in the pedal's sound. Also took out the 2n7000's, exact same result. The pedal sounds the exact same with or without the 2N7000's/germanium.

What am I doing wrong?

 

[BuddytheReow]

Would need a see a schematic, but it's not up yet on the main site. Which version do you have?

 

[DeadAirMD]

Yeah that's also the problem, don't have build docs/schematic. I have the current version that is for sale.

 

[Cybercow]

Here's the schematic and build doc for the V2 of the ADHD Drive . . .

 

[Robert]

Here's the schematic for the new/current version:

https://docs.pedalpcb.com/project/Schematic-ADHD.pdf

 

[giovanni]

The diodes and the 2N7000 both work as hard clipping diodes. You should definitely notice a difference with or without, more pronounced at higher gains (depending at which point the clipping starts). If you don’t hear a difference, maybe they are not actually in the circuit?

 

[Robert]

Are you sure your germaniums were oriented correctly?

If they were installed backwards you'd get no clipping from them or the 2N7000's.

Also, since the germanium diodes are in series with the 2N7000's removing one takes the other out of the circuit as well, unless you added a jumper.

 

[DeadAirMD]

Thank you for clarifying that for me Robert, really appreciate that. The diodes were orientated correctly, I didn't have the schematic and didn't know they were in series. If I want to use just the germanium diodes, do I jumper the pads for the 2n7000's?

Also, could I put the 2n7000 on an on/on switch and the germanium diodes on their own on/on switch so I can choose which one I want to use?

 

[giovanni]

Thank you for clarifying that for me Robert, really appreciate that. The diodes were orientated correctly, I didn't have the schematic and didn't know they were in series. If I want to use just the germanium diodes, do I jumper the pads for the 2n7000's?

Also, could I put the 2n7000 on an on/on switch and the germanium diodes on their own on/on switch so I can choose which one I want to use?

Since each diode is in series with the transistor you are gonna need some creative switching to make it work. Like you could have a switch to jumper the transistors and one to remove clipping entirely. Maybe there is a way to do both in series or one type only, I would need a piece of paper to sketch out a diagram.

 

[DeadAirMD]

To bypass the transistors do I jumper the DSG of the transistors together?

 

[PJS]

2 of the transistor pins are already tied together, so shorting either of those with the other pin should remove them from the circuit. Main thing to remember is that the forward voltage of the transistor + germanium diode combination is just over 1 volt. The germanium diodes alone have a forward voltage of around 0.35v or thereabout. The pedal as a whole will get a lot quieter with just the diodes. I would be surprised if you could get it to unity volume with just them in circuit.

 

[DeadAirMD]

I see that on the schematic now, nice. I have a Modus boost right after so I'm not too worried about volume. Just want to be able to audibly tell which version of the circuit I prefer.

 

[DeadAirMD]

Well, thank you everyone for all of your guidance and advice. I'm sure there are easier ways to wire this up, but I did it on my own and that's sometimes better than doing it the right way. Set the ADHD up to switch between 1 diode, 2 diodes, or without diodes. Also removed the 2n7000's and added jumpers.