I have a Dunlop UV-1 that's giving a really soft effect. The controls all work and you can barely hear the changes. I've replaced q16-q18 and tested caps with no success. The bulb is working, but seems to either be not getting bright enough or dark enough. I'm getting the 15V on it. What should the voltage range be on the other side?

Can anybody tell from the schematic what it should be?

Dunlop - Univibe UV-1 - Schematic (2-2).pdf

Trying to use up all my 10k pots.

I just realized the schematic is vague about power/bias. The 1M bias is actually going to Vref (1/2 of the positive supply). I'm using a +12v wall wart but it should work fine with +9v.

gesoft-2024-12-31.png

Boxed up with a clean/treble boost in front:

gesoft-2025-01-01-front.jpg

Attention Peavey Vypyr Generation 1 Amplifier owners.

I posted this over at the Peavey forum, but it might not see the light of day.

As mentioned by other members of that forum, the original Vypyr Librarian had problems and was abandoned before being fixed.
The biggest problem is writing all presets to the amp - it doesn't work correctly.

Now, for purely educational purposes, I would like to share with you something very interesting.

If a few bytes in the Librarian v1.00 software were...

TLDR: Here is the schematic for the Landtone Delay pedal. It is a Tonepad Rebote 2.5 . I’m not sure you call it a clone if the original pedal is a DIY pedal.

This is my second trace here. I’m waiting for the paint to be finished on the first one I traced and built. It would be really nice if Landtone included the drawings with their pedals – but hey, cheap stuff from China, right?

I’ve physically traced the entire circuit.

I made sure to label the PT2399 U2. All delay chips should always be...

When modding, I often reach for my basic scientific calculator to enter the RC filter equation f = 1/(2 * PI * R * C).
The other common use is for parallel resistors or what value do I need to use in parallel with x to give me y?
But entering the values with their negative exponents and 2nd-key functions can be a little tedious.

Obviously, what I needed was a programmable calculator to store these programs and make it a bit easier.
My old TI-56 is very limited programmatically and is not up...

He sorts his germaniums into low, medium, and high gain. Just wondering if anyone knows what the gain ranges for each of those are? Is his low gain 20-30uA, 30-70uA? Seems like one person's low gain could be another person's medium.

I got one quite cheap and like it! It really has that 60's Fuzz Tone sound and more, with the added tone control and octave switch.

Enjoy!

Fender - Hammertone Fuzz.JPG

Pics and more info can be found on my blog. Link in the sig

The pedal works perfectly in 8 second mode. However, when I switch to 2 or 1/2, the effect doesn't work. When it kicks in, it basically doubles the signal overtop of the input, i.e. Just makes the sound a little warmer. There are no trails, echos, or repeats. The delay controls don't seem to change anything. The controls all work perfectly in 8 second mode however. I've recapped and swapped ICs. I get the voltages on the 4066 when sliding the selector switch. Interestingly, if I jump pins 3&4...

I have been interested in pedals, and I knew nothing, but I wanted to learn. So I just sort of started buying the cheapest versions of effects I could find to see what's in them and see how they sound. I still now almost nothing, but in the process of exploring things, I accidentally found the very cheapest way to get pedals shipped to the US.

If you are interested, below are some price examples so you can see what I mean, and my method for using AliExpress....

Another curious question of mine, are claims of a BBD chip inside true? This is the cheapest 4-knob flanger I could find so I grabbed it for $10 shipped.

Inside I found an MN3207 BBD, an MN3102 Clock Generator, 2 x RC4558, and an 062C. Three trimpots all with the index mark at exactly 6:00 and 12:00, which makes me wonder if they'd been adjusted after assembly at all. I'm still playing with it before I dare adjust those.

IMG_20241124_150956.jpg

IMG_20241124_151009.jpg...

Hello.
I traced a DemonFX Omicron Darkglass that appears to be a copy of the Omicron Darkglass Alfa. I ordered a few PCBs with the schematic I traced, and it works just like the original (Demonfx). The only thing I have changed is the switching bypass, which I have made truebypass (the original used a CD4003 and JFETS). The rest, as is. Here is the schematic, in case you are interested.

I recently bought a Surfybear Compact and after I put it on my board I had an interesting issue. The Surfybear Compact has a decay dial but it didn't work when on the board. It would always be maxed out.
After some testing the culprit was found. It was the J. Rockett Archer Ikon. After contacting Surfybear someone there explained how the decay circuit works and that loud signals could mess it up. A short search on the net showed me that other people had issues with the Archer messing up...

Usually suprised at the quality of their pedals. I have their v3 ep or bp comp, black one, and it’s pretty good. I’ve attached a pic of the version before mine as the last pic. I’d have to take mine apart and haven’t felt like it. Actually the comp is first. Have no clue what the goop is covering. It’s optical. Supposed to have an EP style boost.

Hi everyone,

I've been checking this forum for years, but this is my first post here.

So, I tried to add a mono jack to my EHX Freeze to use with an external switch, as instructed in this video (starting at 4:00):

So far so good.

However, my external switch (a mono keyboard sustain pedal) is working erratically.

I mean, sometimes it works when I press it, sometimes it doesn't. It's not practicable.

I check it with my keyboard, and it's working fine.

Does it have anything to do with...

Got my Mosky Silver Horse yesterday. Tried using it and after a day this is what mine does.

Can’t return it coz I sourced it from AliExpress via another country. My mom in law carried it for me. I’ve raised a dispute with AE and written to Mosky as well. No luck so far. Trying some DIY repair if possible.

Any tips on how I should go about this ?

Any checks I can do to figure out what component is causing this ?

Tests I’ve done so far :

D2, D3 and D4 have around 0.6V reading when...

Hello guys,

im having troubles to find what is going wrong with a Truetone Liquid Chorus and Echo Version 1. It was not turning on in the first place but i found a shorted cap close to the DC input, then i could turn on the pedal but it was acting like a bypass even though the leds indicate that either echo or chorus are ON. I found wrong voltages on the 2x 4558 op amp, i replaced them by 2 tl072 and recovered the right voltage on only one of them 4,5V on pin 123 and 567. The other one show...

So basically I just soldered a TRS jack between the output lug of the feedback pot and the pad where the lug is supposed to go. Pedals can go as inserts in the loop, but I noticed the PS-2 will start to oscillate when the pot is set to noon instead of 3 o'clock like it normally does when using pedals in the loop. Otherwise feedback behaves normal. Any ideas on how to solve this?

Small convenient practice tool that clips onto a belt. Plug an instrument or pedal board into one end and headphones into the other end. Powered by a 9v battery fit into a 1590A size enclosure.

GBisson_EHX_HeadphoneAmp_Schem_2024.10.25.png

EHX_HeadphoneAmp_top.jpg

EHX_HeadphoneAmp_bot.jpg

I got one in as it was cutting out while gigging. The IC socket was really loose and I could almost let the IC fall out of the socket. I added a new socket and now the unit functions again like it should.

Menatone - Red Snapper Mini.JPG

More pics and text on my blog; check the link in my sig

Hi all!

I got a reissue OD-850 in from Ibanez.
Traced the pedal and put it next to my vintage unit. They are quite similar.

OD850 RI.JPG

I added a lot of pics between my vintage one and the reissue on my blog; check the link in the sig

Hi all,

My first try at tracing a circuit and third layout.
The circuit has an input + buffered output and an xlr ofc.
Versatile as it can be powered 9-16VDC or by phantom power.

The layout is verified , as I built it a few hours ago and works perfectly !

Peavey-EDB1-schematic.png

Row H can be ommited as it is not connected to any component.

Peavey-EDB1-layout.jpg

Cheers !

I didn't see another thread about this one, so posting it here.
I picked up a new 2024 MXR YJM308 Overdrive yesterday and in the process of reverse-engineering it.
Many people speculated would just be based on the Fender unit or DOD YJM308, but this appears to be unique with through hole parts on top and SMD on the bottom!!

Still working on the BOM and need to confirm the SMD components, but here is a DRAFT BOM.
How does it sound....good. The original DOD308 I liked, but has a lot of bottom....

Germanium or silicon guns?

I was eyeing one for some time. The sound is like a muff but with more mids and a great selector switch.

EnjoY!

Biyang - FZ-7.JPG

More pics can be found on my blog; check the link in the sig

Hello everyone, this is my first post here and I am looking for some help. Please keep in mind that I am a novice with electronic repair and reading schematics but I am learning. So I’m starting my journey into pedals with a phase 100 script circa 1975. It came in the mail a few days ago and while it mostly works it does have a couple problems.

It is a little bit of a noisy pedal but that might go away after it warms up a bit or if I change its location in my chain, I’m not sure about that....