Hello! I’ve just finished the Jext telex white pedal using the layout over at tagboard effects.. I’ve quadruple checked everything and it all looks good.. however there’s no signal. .. main change was replacing the 220r under Q4 with a jumper (this was recommended to prevent oscillation late in the gain sweep). Other difference is I added an extra cut and jumper simply to accomodate the inductor. I tried turning the bc548 transistors the other way round .. no change. Double checked pinouts...

Hello.
I have analyzed the schematic of a TBCFX mep3 pedal I have on hand.
The FET was unknown.

I will share it with you since I have it.

I am using translation software for this text.
Please forgive me if the text is strange.

PDF: Hobby-Electronics-1979-06-S-OCR Tremolo Unit.pdf

Hobby-Electronics-1979-06-S-OCR Tremolo Unit.jpg

I’ve been dinking around on a fuzz face on a breadboard for a few days now. I’ve got it pretty dialed as to how I want it at this point. One problem though no matter what I’ve done doesn’t seem to change. When I use my strat (stock 2020 players) if I turn the volume knob below about 8 I have no sound unless I have the fuzz turned all the way up (I initially was following the directions from small bear that says use a 1k anti log so this makes the turn it all the way up even worse I think, I...

PDF Poptronics-1980-06 wah wah.pdf

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PDF: Poptronics-1974-03 tremolo adapter.pdf

Poptronics-1974-03 tremolo adapter.jpg

PDF: Elektor-1979-12 Talk funny.pdf

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Howdy!
I like the look of the Urei Mod One discrete opamp. It uses 5 BJT transistors.
My question is how do I adapt this circuit to germanium BJT transistors? Got a bunch of Soviet ones and would like to use them! I am trying to learn the math behind it, so I'd like to learn why/how it works or doesn't work.
Can I reverse engineer from silicon BJTs? (Essentially the opposite of this:
Thanks for your help in advance!

I've been reading this forum looking for a schematic for the wah pedal I have, which has a 6 position rotary switch on the side, and green/red LEDs on the top. I can't find an accurate schematic for it (most schematics I can find don't has as many ICs as mine).

I think it is a 535, not 535Q.

Happened to have a schematic for it?

Picture of the electronics (I don't have a bottom plate where name would be):

Thanks!

Anybody have the schematic for the Yamaha DSC-20M chorus pedal? Pedal works under battery, but plugging adapter in kills all life; D2 diode also does not look original.

PDF: Hobby-Electronics-1981-12-S-OCR Graphic EQ.pdf

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PDF: Practical-Electronics-1975-08 Fuzz effect.pdf

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Hobby-Electronics-1981-07-S-OCR Treble Booster.pdf

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PDF: Pop-1972-07 Optimum Fuzz.pdf

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I apparently have a thing for delay/reverb circuits. I decided to do a true stereo reverb using PT2399. It's based on my Spare Room design, but it takes advantage of of the ability to cross feed the left and right signals and to do some cool cross channel-dependent modulation. It's not a small circuit by any measure. In fact, it may be the most complicated single knob pedal in the DIY world, but it's a fun one. The schematic is too big to post at reasonable quality here, but I put the short...

PDF: ETI-1980-04-80 UK Preamp and Power amps.pdf
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hey guys
i just built one, i tried a lot of transistors and finally got some nice sound out of it. bias voltages are ok, no ugly noises on the decay
its gated in a nice way, with a hint of octave up when i back the guitar vol pot a little....
what bothers me is on a certain combination on the guitar volume pot and the fuzz''/ bias pot in produces a kind of octave down sound which is actually very pleasant
my question is whether this is normal. i havent heard of a zonk pedal doing this

i...

So I have a DL-4 that powers on maybe 1 out of 10 times. When it does power on, it works totally fine and indefinitely. Sometimes if I unplug it after working then plug it back in, it works. Most of the time it doesn't. After that, it seems like 2 consecutive times powering up is the limit. I've reseated the Eprom several times and thoroughly cleaned the pins. I reflowed all of the pins of the socket. I reflowed a few ICs around the Eprom to see if something was just making a bad contact. I've...

I have built an old favorite from this board, the Highway 89 from Doug Hammond. This pedal kills. The tone is rocking and ballsy and the clean up is great!!

I was trying to let the other guitar player in my band use it and I discovered a really strange issue that we have tracked down to a power issue generally but do not know specifically what the problem is.

When it is powered from my old dinosaur SKB pedalboard the pedal works fine, as it does when I use a single Boss PSA 120 style...

I have extra boards from some pcbway orders that I've decided to offer up stateside.
●●●this is for USA shipping only●●●

They are all verified.

There's multiples of each pictured.

$5 shipping included will get you whatever boards you want, up to one of each design.

To be clear for $5 you can get all 5 boards shipping included.

●●●this is for USA shipping only●●●

I'm open to trades for boards that you have extras of.

Pm me if interested.

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MXR Blue Box

Mesa...

I got this unit in and it sounds great on the bass

I was expecting more of an Overdrive unit but I got a distortion pedal. Sounds also great on guitar!!

Trex - Bass Juice.JPG

Hi all, my line6 m13 has blank lcd screens. The colours still change and the effects all still work. But unfortunately the lcds are either blank or sometimes all black. Looking online it seems like a few people has this issue but I haven’t found a way to repair it yet.
Does anyone have any advice? Thanks

This is side A of the Duellist dual pedal released as a standalone effect. It's got a couple of changes from what's inside the Duellist, but overall pretty close.

king_tone_soloist_trace_schematic.png

Basically a stripped-down Tube Screamer (Son of Screamer) with several tone options.

Full tracing journal: (includes Duellist and Heavyhand)

PCB:

This is side B of the Duellist dual pedal released as a standalone effect. It's got several tweaks & added features from what's inside the Duellist, so not a direct clone, though pretty close.

king_tone_heavyhand_trace_schematic.png

Basically a Bluesbreaker/Prince of Tone with a clipping diode switch and a few different pre-clipping tonal options.

Full tracing journal: (includes Duellist and Soloist)

PCB: