Forum dedicated to helping people debug and troubleshoot non-functional pedals or builds. Please use an clear and informative title, indicating circuit and basic problem. Don't forget to mark the issue as fixed if this is the case.
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Debugging 101 General rules and hints to succesfuly bring back that old pedal to life
I have wired a 6N17B following the Fender Twin schematic and pinout from Frog preamp build doc. From the top 1 (plate) is at 7 then clockwise 8 (heater), 7 (grid) and 6 (cathode)
For the heaters I am using a IRF830 as voltage regulator to output 6.3V @500ma and as dcdc converter I am using a nixie psu 9V to 200V
The plate voltage is about 197V and I am using 100K on plate, 1M to ground +68k grid stopper and 1k5 on cathode
On the cathode there is no current flowing. What could be? Bias...
I am trying something called the DownBox, after running into a random schematic here:
I haven't been able to get it to work after a couple tries. I have not been able to find much info about the build from my searching. Curious if anyone has built one successfully, or if anyone sees an obvious problem with the schematic?
I am using 5088's instead of 5089's. I also had to use a polarized electrolytic cap for the 470nf in the middle-left of the schematic. Otherwise everything is...
I came across the layout from and thought I would try it out after reading the entire post. I successfully got the fuzz effect going, but I get no octave effect at all.
Here are the measurements I have taken so far:
Q1 - MPSA13
C: 3.36v
B: 1.15v
E: 0
Q2 - 2N5088
C: 8mv
B: 0.44v
E: 7.99v
Q3 - 2N3906
C: 8v
B: 7.43v
E: 0
These are water clear blue LEDs
D1: 3.36v (this is the only one that lights up when I play thru the circuit)
D2: 7.99 (I forget if this is v or mv)
D3: 0.44v
Hi everybody !
I have a Danelectro Cool Cat Vibe with a problem :
it worked great for a few years, but suddently, the speed knob is acting strange : It's like if the speed is now a lot more fast than before. At minimum it's the same speed at, say in the middle when it worked normally, and then goes really fast, so fast that when I reach the middle of the pot travel, the speed is so fast that you can't hear any modulation.
I built a few kits and stripboard, but I consider myself still a newb...
Hello all. I'm new to the forum so I hope I'm doing this right.
I recently acquired an original Dunlop 535 Non Q Crybaby but it looks like someone has tampered with the mini PCB for the Rotary Switch. There are several capacitors and resistors missing and I'm not entirely sure the capacitors that are there are the stock values either. I would like to get it back to stock if possible but I'm having trouble finding a schematic that I trust. The only Non Q schematic I could find was from an...
Hey,
Just completed a 'Hundo' TA-100 clone on a board from Effects Layouts; using 1N34As and MP42B pnps with HFe tested around 80.
It sounds great *IF* I touch the case of Q2, otherwise it sounds quiet, farty and terrible. It isn't an intermittent issue, just works if I touch it. The other issue was the volume did not work unless I grounded pin 1. I reflowed the Q2 and vol pads but the issues persist.
Hi all, I've just finished putting together the Red Ryder that was posted on dirtboxlayouts in January, but the clean signal is really low in volume compared to the distorted side - the schematic is here
:Red Ryder
I've checked my board and connections and was wondering whether it's possible to increase the volume of the clean by wiring the opamp buffer on the top of the diagram into a non-inverting amplifier, or just altering the value of the 15KΩ resistor after the buffer?
So I got in a Dunlop univibe UV-1 revision A that doesn't fully work. The vibe/chorus effect is really weak when engaged. The voltage regulator is fine. Upon removing the shield, I see the bulb is flashing but what seems to be very dull. The speed changes the rate of the bulb, and the intensity changes the flash down to a not blinking at all. But it seems to me like the overall brightness of the bulb isn't strong at all. I'm not sure if the problem is the bulb itself or the driver. What kind of...
The pedal is a Ibanez PT-9 from the 80´s. I have a second one to compare to.
The issues are as follows:
- Only when in bypass-mode, it makes a whining noise when feedback is full cw
- When in effect-mode, the modulation only starts way up high on the speed setting and sounds strange, sort of weak...
What I have noticed is that there a four solder-connections that are somehow oxidized and impossible to reflow/resolder.
The legs of these...
Hi all! I have this dead effect after bad repair... I made schematic of it but I not checked it. So It can has mistakes. And It can has sligth difference in some capacitors values greater than 2u2. So check it please if you will make it and dimentions too.
In PCB I saved original topology (check ZIP file).
My Mooer Preamp is dead. It was working fine until yesterday. It powers on but just flashes all the lights after booting up and no sound. Any ideas?
I already did a factory reset.
Anyone have schematics?
Sorry im new and desperate without my FuzzFace. Its modified with 3 extra dials - 2 tone and 1 bias. And there is no power input other 9V battery.
So a wire came off the input jack and i think a new jack is needed too after i soldered the wire - it no work.
- Do i need to use a stereo jack? As it has more than two tabs, meaning its stereo.
- I was asked by one supplier does it have an internal switch....... i dunno.
It has 2 of the same enclosed jacks which ill get a spare when i order. See...
Hi. I'm a retired electrical engineer. Back in the early 70s I disassembled some early EHS stomp boxes including an original Big Muff Pi and Small Stone Phase Shifter, Electric Mistress Flanger, V2, along with a circa Y2K Octave Multiplexer and a homemade EQ/Boost circuit with a small power supply and some other tonal mods and assembled all the removed boards/pots/switches and hardwired them all together to form what I named The Squaking Owl . I played with it for many years and decided...
I recently designed a tremolo circuit for a build I am doing, and I am struggling with it. The basic design is a uni-vibe style LFO (That I took from the EQD The Depths) with an inverting op-amp in unity gain afterward. This powers an LED, which works in conjunction with KE-10720 photosensors that power the bias voltage of an op-amp in a non-inverting configuration. This is doubled and put after two HP or LP filters. I then put another op-amp in to make up gain, and then a treble booster at the...
I bought a used cry baby JH-1 which has very little head room. Setting the volume above 8 on a strat leads to a dirty distorted (but not in a good way) sound, whereas I remember using a standard Cry Baby many years ago and always getting a very clean sound.
Is it a feature of the JH-1? If so, I probably want to convert it into a regular GCB-95. I remember stumbling upon a set of schematics of the various versions but can't put my hands on it anymore. Anybody knows of a link?
If not,...
I Got this m wave mini universe reverb pedal some time ago. It sounds absolutely killer, but there's a problem with that lts been there since the beginning and lots of people also experience it.
When engaged, it pops! It pops and introduces this into the reverb sound. The weird thing is, the longer the pedal stays active, the lesser this popping effect becomes when switched on and off. It makes me think of a capacitor issue, but seems like lots of people complain about it on YouTube comments....
I have a vintage TC Electronic Sustain + Par. EQ that has low effect output volume. I already replaced the bad 10uf caps. The bypass signal is fine but the effect volume is significantly lower. I know this isn't inherit to this pedal, so I'm looking for a repair, not a mod. What component/area should I look to next?
I've recently got a Donner DT-1 tuner, which is cheap and functional, and also has a great compact size.
However, I've noticed that despite being True Bypass, whether it's powered or not, it somehow clips my guitar signal a bit and it inevitably affects the other pedals that follow in the chain.
Normally I plug my guitar directly into my sound interface (Behringer UMC202HD) for years and set a safe amount of input gain and play/record. This way, I have no distortions, or digital clippings, or...
Yesterday I bought two vintage Japanese boss pedals, a CE2 and a PH1r. Both early 80s. They were dirt cheap, $125 Canadian for both, but not in great shape. The chorus works pretty well, but the phaser isn't working.
Everything is great in bypass. The switch works, led lights up, but not much change in sound. No phaser sound at all, but the resonance knob works. It actually sounds great, a bit of a boost, nice thick sound, just not a phaser. I'm considering building just the...
Hello, I'm about to build a delay with tap tempo, but I've tried a few designs and they all have tempo noise that is heard in the speaker. Have they told me that the noise is caused by the micro controller? In my case I will use an ATMEGA 48/88.
What is the secret to avoid getting these noises? the pcb design?
some kind of filtering on the microphone? Should digital grounds be separated from analog grounds? or do they have to be joined?
If anyone can help me, that would be fantastic!
thank you
I cross-posted this but the other version was in a thread about the EHX Echo Flange, and I understand how that could seem daunting. However my question is fairly generic, I think...
Original post:
I have two questions regarding this schematic. This really relates to the original schematic but Paul's re-draw here is much easier to follow so we'll go with that.
1. Are C6 (50uF) and C7 (50uF) redundant parts? This looks to me like they could be replaced with a 25uF bipolar cap, but there may...
Hello.
I built a vintage univibe clone, and it works flawlessly in regards to the vibe function, yet, there is some separate noise sneaking through. The noise is a swish swish swish with the bulb flash that is separate from the vibe effect sound. All other aspects of the pedal function perfectly, the throb is perfect , the tone is perfect, everything, yet the pedal picks up some type of bulb flashing interference, a secondary swish swish swish sound , and when you turn the pedal off, the...
Hi. Looking at a fuzz for a friend and it's got a strange problem that i've not encountered before. It's a MK1 Tone Bender type (Maestro FZ-1, Zonk, etc) made by someone that's not me and it sounds pretty good but when you really dig into a chord, especially a low one it seems, there's a brief volume sag before returning to nominal volume. The resting bias on all transistors looks appropriate for this type of circuit but apparently something is briefly bringing it out of whack when its given a...
I've just got started with pedal building, specifically doing it from scratch (i.e. not from kits). I already have a basic understanding of some analogue electronics - particularly opamps - so I've worked up from a clean boost to an overdrive and now I'm looking to do a high gain distortion.
My current plan is basically clone the Rat and use it as a base to create my own derivative. I'm going from the schematic and analysis on ElectroSmash (of course).
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