SOLVED Thermionic Distortion. No Audio.

[Dean.cfh]

Hello,
The thermionic distortion is my first major pedal build with switch, LED’s, ect., and when I turn the effect on, there is a hum (sounds like lots of gain with no gate) and all of the knobs work. When I turn any of the potentiometers up or down, I can hear they have an effect on the hum. For example, if I mess with the bass knob, the bass can be boosted or cut out of the hum, same for all the other knobs. The LED, bypass, and potentiometers work, but overall, there is no sound from my guitar to the amp. I will have a volt meter with me tomorrow, so I am hoping to get a few suggestions to try out after work. Only thing I have tried so far is testing the effect in and out of its enclosure and nothing changed.

 

[Betty Wont]

Make sure your jacks are wired sleeve to ground, and your tips to your in and out.

 

[Dean.cfh]

Make sure your jacks are wired sleeve to ground, and your tips to your in and out.

They are wired accordingly. I am using stereo jacks instead of mono but I am still using the correct lugs for hot and ground. I even cut off the rings for the extra lugs that stereo jacks come with to make the jacks mono. I could be wrong, but I do not think this is the issue because my pedal does work when I bypass the effect. Audio disappears when I turn the effect on.

 

[Dean.cfh]

Hello,
The thermionic distortion is my first major pedal build with switch, LED’s, ect., and when I turn the effect on, there is a hum (sounds like lots of gain with no gate) and all of the knobs work. When I turn any of the potentiometers up or down, I can hear they have an effect on the hum. For example, if I mess with the bass knob, the bass can be boosted or cut out of the hum, same for all the other knobs. The LED, bypass, and potentiometers work, but overall, there is no sound from my guitar to the amp. I will have a volt meter with me tomorrow, so I am hoping to get a few suggestions to try out after work. Only thing I have tried so far is testing the effect in and out of its enclosure and nothing changed.

 

[BuddytheReow]

Stupid question, but is the guitar and amp plugged into the correct jacks? Don't laugh, I've done it...

 

[Dean.cfh]

Stupid question, but is the guitar and amp plugged into the correct jacks? Don't laugh, I've done it...

Yes they are. I actually did make that mistake when I was testing the effect outside the enclosure because the pcb was flipped and I got scared everything stopped working lol.

 

[BuddytheReow]

Do the LEDs turn on when signal goes through. Not the "power on" LED

 

[Dean.cfh]

Do the LEDs turn on when signal goes through. Not the "power on" LED

When I turn the effect on, they will flicker. I have not tried adjusting the knobs or the trim pot outside the enclosure. When I turn the effect on, I have all knobs set at 12 o clock while the trim pot is set at like 3 o clock.

 

[Dean.cfh]

Do the LEDs turn on when signal goes through. Not the "power on" LED

I just tried setting everything on max including the trim pot and when I plug in my 9v power supply, all 4 LED's will flash. When turning the switch on or off, only the left LED's will flicker. When turning off the power supply, all 4 LED's will flash.

 

[falzhobel]

I've had a lot of trouble with those and also the Thermionic Deluxe. It seems that there are "cut" on the PCB that appear randomly and you need to probe them to solve the issue.

I don't know why this specific design seems to have trouble. I would normally guess that I hurt the PCB with my Iron but on batch of those, I always have 2-3 non-working unit

Have a look at "Audio probe".

 

[Dean.cfh]

I've had a lot of trouble with those and also the Thermionic Deluxe. It seems that there are "cut" on the PCB that appear randomly and you need to probe them to solve the issue.

I don't know why this specific design seems to have trouble. I would normally guess that I hurt the PCB with my Iron but on batch of those, I always have 2-3 non-working unit

Have a look at "Audio probe".

I have never heard of "Audio probe." I will most certainly look at this and see what I can do with it.

 

[BuddytheReow]

For the record, only the 2 LEDs on left will light up when playing. At least, that's how it is on mine.

 

[Dean.cfh]

For the record, only the 2 LEDs on left will light up when playing. At least, that's how it is on mine.

That is what mine does. I am going to try that audio probing technique the guy above suggested and see if that helps.

 

[BuddytheReow]

That is what mine does. I am going to try that audio probing technique the guy above suggested and see if that helps.

Just do a quick google search for diy guitar pedal audio probe. You will have to make one with a guitar cable and a capacitor. I think SmallBear sells one if im not mistaken. Up to you.

Also, check the voltages on your IC pins starting with the upper left hand corner and going counter-clockwise. Those are pins 1-8 in that order. Post them back here jsut to make sure power is flowing correctly.

 

[BuddytheReow]

Also post a pic of the back of the board. There may be some bad solder joints

 

[Dean.cfh]

Also post a pic of the back of the board. There may be some bad solder joints

 

[Dean.cfh]

Just an update for you all, I fixed it! The issue was the input from the switch onto the pcb. I noticed in the pictures above, the connections were very sloppy so I decided to heat the solder and let it drip down into the holes more. Once I did that, things worked!

 

[mjh36]

Good stuff man I'm glad you found it, cuz that pedal rocks.