Author Topic: Graciously requesting help troubleshooting a pedal I built  (Read 3527 times)

Silasmoon

Graciously requesting help troubleshooting a pedal I built
« on: August 03, 2014, 04:11:13 PM »
Howdy!

Schematic:


Here is the schematic - veroboard for green citrus MKII. http://guitar-fx-layouts.42897.x6.nabble.com/file/n10083/001-GreenCitrusMKII.png;cid=1405276443201-225


The question marks are for biasing the transistors correctly. I am using sockets for the transistors and the resistors while biasing.

Photoalbum of Build:
Here is a photo-album of my build: http://imgur.com/a/gmXJ3#0

Deviations from Build:
Did not install the LED on the board, nor the LED+ wire. Instead I used the following offboard wiring: http://1.bp.blogspot.com/-k5Sh68yVU18/TzGRFKbiALI/AAAAAAAAAlk/CbfaaduUjYQ/s1600/%21Offboard+wiring.png


I also swapped the J201 for 2N5457 for Q3 and Q4 - would this make a huge difference?

The pedal is fine in bypass mode, but makes no sound when engaged. The light turns on correctly with the foot switch. I re-checked solder joints, measured my resistors as best I could without desoldering the whole thing, and checked the voltages on the leads on the power rail is 9v. What's curious to me is that with this design of the 3PDT offboard the LED power is connected to ground when the pedal is engaged. I've used this wiring schematic before with success, but just now noticed that my ground and LED complete a circuit when it's on, and wasn't sure if that was correct.

Measuring with 20V dmm

Q1:
G - 0.0
S - .9
D - 5.2

Q2:
G - 0.0
S - .95
D - 5.0

Q3:
G - 0.0
S - 1.5
D - 2.4

Q4:
G - 0.0
S - .7
D - 6.8

Thank you so much - let me know if you need anything else. :)
« Last Edit: August 03, 2014, 06:21:44 PM by Silasmoon »

LucifersTrip

Re: Graciously requesting help troubleshooting a pedal I built
« Reply #1 on: August 03, 2014, 05:42:57 PM »
I really don't work much with jfets much, but should all gate voltages be 0?  You didn't post a schematic, which is why you'll get less replies, but according to a thread on the Green Citrus V1, all the drain voltages were 4 - 5V

http://www.diystompboxes.com/smfforum/index.php?topic=71597.msg582157#msg582157
always think outside the box

Silasmoon

Re: Graciously requesting help troubleshooting a pedal I built
« Reply #2 on: August 03, 2014, 06:22:32 PM »
Ah! Forgot that - added the proper schematic as well. I am very new to pedals, so I just go off of vero layouts. Yes - there is a lot of biasing that needs to be done as well. I tried to get each one as close to 4.5 - 5v but realized that I might need a larger array of resistors.

Silasmoon

Re: Graciously requesting help troubleshooting a pedal I built
« Reply #3 on: August 03, 2014, 06:29:39 PM »
Here is a video demonstrating my confusion in regards to the LED and grounding. Not sure if this is the proper way for this to be laid out. https://www.youtube.com/watch?v=hQws9umqNN4&feature=youtu.be

Govmnt_Lacky

Re: Graciously requesting help troubleshooting a pedal I built
« Reply #4 on: August 03, 2014, 06:31:28 PM »
Looking at your vero layout, the transistor in the upper right corner of the board does not appear to have the Gate attached/going to anything  ???

IT looks like it goes directly from the gate to a jumper which leads to nothing....

Am I seeing that wrong?

EDIT: I think your vero layout needs more work. IT does not match the schematic bro!  :-\

EDIT2: Looks like you have an un-needed trace cut that is preventing the Q3 Gate from getting to the Treble Lug 2. Try fixing that and seeing what you get  ;)
« Last Edit: August 03, 2014, 06:39:23 PM by Govmnt_Lacky »
A Veteran is someone who, at one point in his or her life, wrote a blank check made payable to The United States of America
for an amount of ‘up to and including my life.’

Silasmoon

Re: Graciously requesting help troubleshooting a pedal I built
« Reply #5 on: August 03, 2014, 07:37:09 PM »
Oh - adding that jumper did it! Will mess around with it some more, but I think we've solved this one.  ;D Thanks everybody!

Govmnt_Lacky

Re: Graciously requesting help troubleshooting a pedal I built
« Reply #6 on: August 03, 2014, 07:51:54 PM »
Gald you got it working. How does it sound?  ;)
A Veteran is someone who, at one point in his or her life, wrote a blank check made payable to The United States of America
for an amount of ‘up to and including my life.’

Silasmoon

Re: Graciously requesting help troubleshooting a pedal I built
« Reply #7 on: August 03, 2014, 08:04:35 PM »
Well - not anywhere close to what I was expecting to be honest. I was going off this vero that someone else had made. I am a total hack and really only build from these vero layouts.  :icon_cry:

I am wondering if my lack of J201's is mellowing it out. Was hoping for that chuggy MATAMP sound.

Govmnt_Lacky

Re: Graciously requesting help troubleshooting a pedal I built
« Reply #8 on: August 03, 2014, 08:09:19 PM »
I am wondering if my lack of J201's is mellowing it out. 

You never know until you try 'em  :icon_cool:
A Veteran is someone who, at one point in his or her life, wrote a blank check made payable to The United States of America
for an amount of ‘up to and including my life.’