organ donor volume drop

[Funnel]

Hi, I built the organ donor and the sound is perfect except for a slight volume drop.

 

[smithcircuits]

Same thing happened with mine. womp womp

 

[Cybercow]

Instead of using my two previous (failed) attempts, I finally went with a modified GuitarPCB "Stage-3" PCB. It tucked nicely into the enclosure with the need to shift anything around. Apparently, trying to futz with the gain of the Arachnid platform either introduces unwanted distortion or no gain results at all. But this works very nice. I used a multi-turn trimpot on the volume control of the Stage-3 PCB for fine tweaking. A single turn trimpot will certainly suffice. (the other trimmer is just for biasing the JFET)



In the schematic below, the J113 is best suited for the TR1 & R4 values. The other JFETS suggested may require increasing the values of TR1 and or R4.

 

[music6000]

It will be handy when this becomes available!:

3PDT Breakout Board with Output Boost - PedalPCB.com

Breakout Board

www.pedalpcb.com

 

[djmiyta]

So I made a board from the schematic above and after fixing a sstuuppidd mistake (diode in backwards) I now have 8.77 v on the jfet and can only bias it down to around 8.45v I\ve wired it in where the organ donor output goes to booster input and booster output to organ donor output..
Oddly the boost boosts the volume when organ donor is on or off. Any ideas?

 

[chris.knudson]

So I made a board from the schematic above and after fixing a sstuuppidd mistake (diode in backwards) I now have 8.77 v on the jfet and can only bias it down to around 8.45v I\ve wired it in where the organ donor output goes to booster input and booster output to organ donor output..
Oddly the boost boosts the volume when organ donor is on or off. Any ideas?

Check your resistor values. It's been my experience that boost levels come down to resistor values.

 

[Cybercow]

So I made a board from the schematic above and after fixing a sstuuppidd mistake (diode in backwards) I now have 8.77 v on the jfet and can only bias it down to around 8.45v I\ve wired it in where the organ donor output goes to booster input and booster output to organ donor output..
Oddly the boost boosts the volume when organ donor is on or off. Any ideas?

The Organ Donor Out needs to go to the boost circuit's input. Then the boost circuit's output is what goes to the stomp switch.

And which JFET is being used? The J113 is best suited for the schematic shown.

Show us some good clear photos please.

 

[djmiyta]

The Organ Donor Out needs to go to the boost circuit's input. Then the boost circuit's output is what goes to the stomp switch.

And which JFET is being used? The J113 is best suited for the schematic shown.

Show us some good clear photos please.

Yes thats how I wired it and I used a J113. Whats got confused is 1 - both trimmers (the bias and volume) raise and lower the volume and 2- whether it’s in bypass or turned on the 2 trimmers still adjust the volume of the rest of my pedal chain. That just seems really odd behaviour to me basically it raises the volume of my whole signal chain instead of just the Organ Donor’s. I assumed its that way from wiring it up wrong and /or not being able to bias it to 1/2 the voltage. So I will triple check everything ,can’t be that difficult with as few components as the board has but I’ll take the advice and check resistor values.
Side note looking at the build docs the booster is built from it says “ you may have to remove the 1k resistor with a jumper to bias it. Which I have’nt tried yet (to me removing the resistor would’nt have that much of an effect in biasing ,as it is ,the trimmer only adjusts the up and down around half a volt. But I know a little more than nothing about electronics so most likely I’m wrong
Maybe I’ll try a different boost in there instead if I can’t get this right.
Thanks for the input

 

[Cybercow]

Yes thats how I wired it and I used a J113. Whats got confused is 1 - both trimmers (the bias and volume) raise and lower the volume and 2- whether it’s in bypass or turned on the 2 trimmers still adjust the volume of the rest of my pedal chain. That just seems really odd behaviour to me basically it raises the volume of my whole signal chain instead of just the Organ Donor’s. I assumed its that way from wiring it up wrong and /or not being able to bias it to 1/2 the voltage. So I will triple check everything ,can’t be that difficult with as few components as the board has but I’ll take the advice and check resistor values.
Side note looking at the build docs the booster is built from it says “ you may have to remove the 1k resistor with a jumper to bias it. Which I have’nt tried yet (to me removing the resistor would’nt have that much of an effect in biasing ,as it is ,the trimmer only adjusts the up and down around half a volt. But I know a little more than nothing about electronics so most likely I’m wrong
Maybe I’ll try a different boost in there instead if I can’t get this right.
Thanks for the input

Please post some good clear photos of the build, showing all wiring - front and back. Thanks.

 

[djmiyta]

Please post some good clear photos of the build, showing all wiring - front and back. Thanks.

I will be able to do that in an hour or two .Etched it myself so it’s a bit ugly.

 

[djmiyta]

so I decided to try another simple boost the JHS The Bomb which after wiring in (I put the boost on the out of the 3pdt switch instead of where it now is between the out of the organ donor to the in of the boost out of boost to effect out lug on 3pdt dumb mistake) sSo now everything works perfectly except one thing turning the wet pot turns the volume off meaning Im now getting no Organ Donor Wet Signal playing with the boost out only makes the organ donor louder as it should but now no organizer effect I don't know how but maybe I fried the FV-1 chip? I don't know how sensitive they are and the pots dont line up very good in the box some were further off the board maybe I overtightened one and popped it out

sounds like audio probe time damn shoulda left it alone and dealt with the low volume

 

[Cybercow]

so I decided to try another simple boost the JHS The Bomb which after wiring in (I put the boost on the out of the 3pdt switch instead of where it now is between the out of the organ donor to the in of the boost out of boost to effect out lug on 3pdt dumb mistake) sSo now everything works perfectly except one thing turning the wet pot turns the volume off meaning Im now getting no Organ Donor Wet Signal playing with the boost out only makes the organ donor louder as it should but now no organizer effect I don't know how but maybe I fried the FV-1 chip? I don't know how sensitive they are and the pots dont line up very good in the box some were further off the board maybe I overtightened one and popped it out

sounds like audio probe time damn shoulda left it alone and dealt with the low volume

I'm confused . . . . there is no "WET" pot.

And at the risk of being redundant: Show us some good clear photos of your build please. Both sides of the PCB(s) and all the wiring.

 

[djmiyta]

I'm confused . . . . there is no "WET" pot.

And at the risk of being redundant: Show us some good clear photos of your build please. Both sides of the PCB(s) and all the wiring.

Not a “wet pot” but the mix pot mixing in or removing the wet signal. My bad .Basically there is no Organ Donor effect at all now. Gonna try and get it back original (but not before I get some pictures first) unless it is one of my pots that have gone bad and that I can fix .

I did’nt get a chance (cause I do know better) to get pictures up but I will today.
Thanks for taking a minute to read about my issue .

 

[djmiyta]

It took a while but I got it out of the box and some pics with the boost wired in
When the mix is turned for more wet signal I lose all volume
Before the boost it worked like it should
I saw someone post having a similar if not exact same problem and reflowed the FV-1 chip solving his problem but I don’t think he wired a boost in ,so I MAY give that a shot

 

[Cybercow]

If it worked before the boost add-on then the boost has been miss-wired or the boost is not working properly.
TBH, I am unable to discern how your boost is wired into the circuit from this photos. Can you show a wiring diagram of how it's wired please?
Did you test the boost before you applied it?

 

[djmiyta]

Yes I tested the boost before I put it in. Worked fine and does what it's supposed to do except for the mix pot turning the wet signal off when trying to mix in the wet signal in I wired the boost in taking the organ donor out to the boost in and the boost out to the output jack

 

[Cybercow]

Did you include R6 on the boost board build? It prevents the volume from going to zero when the boost A100K Volume pot is turned all the way down.