Hello,
This is my first pedal project, so please forgive me if it looks like crap.

I though I'd start with something easy, the Lovepedal Champ, using this layout:
which is based on this thread:

The effect works as it should (I think), but I also get a loud hum whenever the effect is switched on. Could it be a grounding/shielding issue?
I have built an audio probe to test it, but I'm not exactly sure where to test, and what I should be looking for.

Here's a picture of what it currently...

I would appreciate any help troubleshooting this uni-vibe issue.

This is the uni-vibe with the vintage button. PCB UV-1 Main Board Rev. A July 10, 1997

Power supply is Dunlop ECB004US 18v
1 Amp.

Effects led briefly flashes as power supply is plugged in. Chorus/Vibrato led works as expected when activated but no effect because sw2 never activates.

Voltage regulator is ok. 18v in 15v out.
Effect switch has continuity when activated.
Ribbon cable from switch board to main board has...

Hi, Guys!

Some years ago my T-Rex Replica damaged due an issue with spike voltage. I tried to send my pedal to T-Rex, I didn't know what was the issue if it was Brazilian postoffice or IRS in Denmark, but the pedal returned to my home. I found a technician in my town that fixed SMD pedals, but this pedal according him it is complex, and he needs the schematic to try to fixed. I wrote to T-Rex, first its answer to change all the audio capacitors, but it quite difficult to him that wants to test...

Hi,
I received this pedal for repair. Totally not working.
Someone could help me with schematic?
Thank you!

This post is mostly for documentation purposes and for future reference.
Maybe it can help someone fix their broken Holy Grail.

I recently got a used, older big box Holy Grail (pointer knob, Rev A, non true bypass)
Though advertised as 'in good working order', there was very little reverb.
Only with the reverb knob at around 4 o' clock (close to 100% wet) I could hear a faint reverb signal. At that point the dry signal had lost more than 90% of its volume.

Being familiar with the circuit I...

Hi,
I Have an MXR Analog Chorus that doesn't apply the effect:

- The original/dry sound passes trought the pedal, in both footswitch positions;
- Its a second hand Pedal;
- I don't have the diagram to troubleshoot;
- I disassembled the pedal and verified that the TP2 is missing, and instead, there is one resistor, with one leg in C16 and another led direct to one of the U3 pins;

I need some help trying to troubleshooting this. Sorry some english mistakes.

Hi all,

This is my first post here so let me know whether I am posting in the wrong section, or anything!

I was wondering whether anyone had success building Tim Escobedo's Q&D VCF, or a variant of it (I understand that the topology is an active bridge-T filter, so variants might be published elsewhere).

simplevcf_252_119.gif

I put the second version on a breadboard with my guitar at the input and a digital cab simulation pedal at the output and all I am getting is a nasty metallic...

I just built up a BB-1 using the V1 layout found here:

Everything works, voltages to the chip pins are all correct, diodes are 4148's showing .63v forward voltage when tested in circuit. The only change I made to the schem was to sub a 330K for the 220K for a little more gain. While everything technically works, I'm getting what I can only describe as too much clean signal on top of the distorted signal. The clipped signal is definitely there, but it just has a bit of this clean signal type...

My trusty 80s Rocktek BBD Delay died. I have soldering skills luckily, and a little experience troubleshooting electronics, but only the easy stuff like blown caps/diodes/burns/shorts. I have a great multimeter that does everything, oscilloscope, soldering iron, and adjustable power supply that will display watts being used.

I tried multiple 9V center negative power supplies that work with others, then I tried a battery, no luck. When I plug it all up and I kick it on/off (I can't tell when it...

Greetings all. I hv a FX90 Delay that is misbehaving. I only get dry signal. LED switching off and on.
I hv a scope, sig generator and audio trace at my disposal. I'm trying to understand how the pedal switches off and on. From the 4007ic it goes to a diode then to the mosfet which actualy switches the pedal off and on. I can hear a signal from the 4007 into the diode but nothing out. I replaced the diode but still nothing. I should hear my generated tone on front and back of diode right?

Hi Guys,

I hope I am able to post these diagrams.

I have built this Lovepedal OD11 clone according to both diagrams. I’m getting a muted volume; I.e., all pots seem to be working, yet there is little volume. You can hear it faintly.

I’m hoping you all can help me out.

I’m using tantalum’s on the uF values.

url=

Hello all,
Here's an odd one. I recently built the AIONFX L5 preamp pedal, which I'm using as a preamp into my pedalboard, then into a Seymour Duncan Powerstage 170 and finally a 16-ohm speaker/cab.
Sounds great...quite loud, especially channel 2.
But here's the thing.
It plays well with all my other pedals save one category.
When I kick on a chorus pedal...any chorus pedal, I can hear the Rate LFO.

Current Signal Chain --Guitar-EQD Swiss Things In--(Loop 1) Fuzz--OD--L5 Preamp--Return...

:applause:
I am new building guitar pedals, I finished this fuzz face circuit on a prototyping board and tested it, everything works! But, once I wired the jacks and 3pdt button, the gain is very very low. The led is pretty bright, you still barely hear the guitar through it when powered on. I will attach my 3pdt schematic and pictures of it below. I got it into a 1550A so it is snug. What could be my issue? Do I need to wire the 3pdt differently? The box is aluminum. The circuit worked in...

Hi all recently got an rc-3 looper missing a volume pot and the little circuit board.

I have a new dual volume pot with 6 poles and four wires one red and three white.

through trial and error i have worked out red wire to pole one, white wire1 to pole 2, and white wire3 to pole 3 is the loop volume circuit.

But can't work out the rest.

i have tried jumping the red and white 3 across to the corresponding poles with white 2 in the middle to no success.

any help or ideas would be greatly...

Howdy All,

Been messing around with the MXR Blue Box circuit and i'm running into an issue. Basically i'm getting a decrease in volume the higher the note is that i'm playing. Notes played on the low E string are loud and clear and as I move up in frequency the volume drops to the point where an open high E is almost inaudible. This happens on multiple guitars and is slightly improved by using the neck pickup and/or rolling back the tone control, but its still present regardless.

Its been...

Hi, just reporting a repair on my 2006 MXR Dynacomp (rev E. with CA3080).

Problem was a frying bacon sound. I removed the socketed IC and audioprobed it. The noise was at both pin 2 and 3, so it was before the IC. Noise was also at the base of the first transistor, and up to the positive end of C2 (tantalum capacitor).

I replaced C2 with a good electrolytic, and noise is gone. Easy one, just make sure you add some leaded solder to the RoHS one before desoldering, makes it easier to desolder...

Hi every one,

A friend of mine gave me a faulty Radial switchbone jx2 (the v1, which looks like this ).
Does anyone have some experience with those ?

Here's what I did so far :
I don't have a schem (and couldn't ffind anything online) so I just traced a bit and tried replacing some components since I had some in stock. I know, it's not very professional... but I'm not a professional :)
The voltage regulator (LM340T12) wasn't working, I replaced it and the pedal lit up (there was kind of a...

Hi guys, I'm trying to fix my EHX POG2. The Dry Output control is not working anymore and I'm not getting any dry signal at the output (when the effect is engaged). First I thought that the slide potentiometer was broken, but I measured its resistance and it looks okay to me. I found this POG2 schematic but it seems to be for the HOG2, although I'm sure it's almost the same unit (or very similar) with more features.

I was wondering if anyone had this problem before or can help me debug the...

What up gangstas! Simple question for :troll: a simple man: can I test the circuit I currently have breadboarded without amplifying the signal? With the components for the circuit, the input, and the 9V battery, will the run-of-the-mill DIY pedal (say, a simple Bazz Fuss or a Distortion + for an example) have enough sweet hot muscle to drive my dollar store in-ear headphones?

I am curious about OD/Fuzz/Distortion/Boost primarily, but am also curious about other effect types. Or maybe not all...

Tremulus Lune - identifying which PCB-maker ('E3'? 'MM'?)

Got a broken tremolo pedal in, it's most likely a version of the Tremulus Lune.

Pots: Smooth/Sym/Speed/Depth/Space

(1) TL072, (1) 4558 and (1) Xvive vactrol, one green dot, so probably a 5C2.

The PCB is marked with 'Tremolo v.1' and has a kind of 'E 3' logo. Or 'M M'?

Anyone happens to recognize this PCB?
Just curious, the generic schematic out there will do the trick, but knowing which circuit version/which maker could come in...

Hi All,

I am a dreaded newbie learning how to build circuits for pedals. My process is I breadboard the circuit, test, then have a circuit board made in order to build pedals for my friends. I just started this process. Well, my problem is, the boards don’t work. I’m getting power but there is no sound when I plug in the cords. I have checked the circuits repeatedly and they are correct per my designs compared to the schematic. I have used my multimeter to check the continuity of the circuit....

Im attempting my first guitar pedal build, im a novice and I was looking for help on my prototype. The circuit is more or less correct and creates the fuzz effect, but when the pedal is off there is no clean bypass. I am attempting to build it without the 9v battery. My led wont turn on, and my volume and fuzz knobs only work when the 3pdt is inactive. Any input helps, I'm sure some of you ran into this problem starting out. I will link pictures below. IMG_5580.jpg IMG_5579.jpg IMG_5582.jpg...

Hey all,

I've got an older Baja Sagittarian made by Mojo Pedals that has a pretty bad switch pop. Would soldering a pull down resistor between the switch and PCB input wire work?

Thanks :)

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