Hi,
I built the Ross compressor clone from I'd swear I had found a youtube video explaining how to adjust the bias resistor, but I can't put my hands on it. Does anybody know how should the bias be adjusted? I think remember it involved making sure that voltage on two legs of the IC were equal, but I don't remember which ones.

Hey, thanks for looking at my post. Some help would be appreciated, if possible.
I've had this FX90 for a few years, just lying around and recently realized/discovered
that it is good for slap back, rockabilly-esque reverb or delay. Slap back... as I said.
It works great and sounds really good with rich tone and a nice slap back, like I was hoping,
but after about 10 or so minutes of use (time may be somewhat inaccurate) it begins
to lose it's effect. It still passes signal whether on or off...

Hey guys,

I don’t really understand how to wire the two switches especially the order switch and how it needs to be wired. Would anyone be so kind and help me out with basic a schematic? The ones I found in the internet where always with three switches and today I’m just too stupid to understand anything and I want to get this build done.

(I think me going from output of the switch to the output jack is also just wrong)

Build documents for the Wolfgang 61:

My status quo (also don’t hate me...

Hello all, I just tried my first pedal mod so some issues were to be expected. I did the R28 Script Mod and Univibe mod using Stinkfoot's guide ( The ony thing I did differently from the stinkfoot script mod was adding an SPDT switch for the R28 mod instead of just clipping the resistor. The Vibe mod seems to work as I did the R28 first and that's when I noticed the issues. Even disconnecting the switch and putting the R28 resistor back to how it came stock didn't fix it. With the switch back...

Namaste

Hi all, I've bought a moen shaky (univibe) new pedal from 2012 and after a month of use the vibration (and rate control) stopped.

any idea?

the light at the 4 leds shines but don't oscilate.

kindly regards

x.

Hi guys.
A friend of mine gave me this MXR MC-402 boost distortion pedal. When I press the BOOST switch the pedal goes death silent. Blue LED comes on but no sound. When I press it again the LED goes out and sound comes back. I checked the footswitch and it works all right. There is a transistor (Q8 on the PCB, J177 I believe) which checked continuity between drain and source when in the circuit but was OK once I took it out. Also there is this IC TLC2262 which tests suspicious while in the...

I have a rangemaster circuit on my breadboard and I am trying to get it to sound right. I tried several PNP germanium transistors which I measured for gain (selected those with 70-160) and leakage (selected those with <150ma). I am not sure I am biasing the transistor right though, so any help will be appreciated. Here is what I tried so far:

I start with a R1/R2 voltage divider where R1 is fixed at 470K and R2 is a 100K trimpot. I adjust R2 to get -1V at the base and then measure the voltages...

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...