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DIY Effects


JackLondon

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[quote name='JackLondon' post='801161' date='Apr 9 2010, 07:24 PM']Right I had enough if this bugger. Anyone can fix it for me? Willing to pay![/quote]


breath in, breath out.... and chill. I took a month of my flipping chorus!
Make an audioprobe so you can follow the signal round the board. Get out the schematic, work out (more or less) what each bit is doing. and then try find where the problem is. I ended up taking mine out the boxes so i could test on both sides.

You'll get htere in the end!

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[quote name='JackLondon' post='800814' date='Apr 9 2010, 01:24 PM']Hi All,

Yeah I posted in on diystompboxes.com and so far they've told me to check off board wiring which I did and it seems fine to me,

here's the schematic for wiring I've followed :

[attachment=46805:wiring.jpg]

This is the picture of the box :

[attachment=46806:IMG_0204.JPG]

There can't be any problems with shorts as the circuits sits on 2 standoffs and a bit of foam, there's signal on C4 and R1 but's it's so quiet that it is almost impossible to hear.

I'm now thinking about the IC's as someone said that pin 7 should be 0V and pin 14 should at least a couple of V, having read the build reports on tonepad I think that my IC's are the ones that are reported as non-working in this circuit. :)[/quote]


output from switch is going to the ground tag on the output jack.

Personally i'd recomend redoing the wiring, remember the shorter the better it'll kill most of the noise to.

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Another pedal that doesn't work, this time Rebote 2 Delay, no clue where it all goes wrong with pedals htat have IC's in them :)

Also as suggested by umph (cheers for that) I reduced the amount of wiring inside the box so it all looks more neat and tidy, but still doesn't work



Any ideas where to start ? The signal goes through the circuit but it's not delayed, so reports from other forums suggest that the delay happens at pin 15 of IC1 but it doesn't in mine. there's no delay at all.

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[quote name='Al Heeley' post='803349' date='Apr 12 2010, 07:48 AM']Thats very neat work there! Have you traced the signal path all the way thru with an audio probe? Have u double-checked you have the IC's in the right way round?
any replacement ones you can slot in and try? what is the 8-leg one, a standard op-amp chip?[/quote]

Yeah I've checked the IC 1&2 and they are correct, the 8 pin one is TL072. Where the first problem was is 5V reg that I put wrong way around, I have some new IC on tye way because I think IC1 is fried. We'll see when it comes.

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make an audio probe and follow the sound through. I recomend some kinda cheap amp to do this too as there will be a lot of popping.

Now i stress i dont know what i'm actually looking at but looking at the schematic i would guess you are getting the signal through R12.

I would then test each bit of the circuit, i.e. pin 12 of IC1, then pin 1 of the threshold pot and go through the whole thing methodically. I personally would also bypass the mods you've stuck on like the switch between G and H just to rule that out.

I had a tonepad board for the chorus and there was a wee break that it took me ages to find.

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[quote name='umph' post='801200' date='Apr 9 2010, 08:12 PM']output from switch is going to the ground tag on the output jack.

Personally i'd recomend redoing the wiring, remember the shorter the better it'll kill most of the noise to.[/quote]

I've done that, thanks for the tip :)


[quote name='LukeFRC' post='804388' date='Apr 12 2010, 11:23 PM']make an audio probe and follow the sound through. I recomend some kinda cheap amp to do this too as there will be a lot of popping.

Now i stress i dont know what i'm actually looking at but looking at the schematic i would guess you are getting the signal through R12.

I would then test each bit of the circuit, i.e. pin 12 of IC1, then pin 1 of the threshold pot and go through the whole thing methodically. I personally would also bypass the mods you've stuck on like the switch between G and H just to rule that out.

I had a tonepad board for the chorus and there was a wee break that it took me ages to find.[/quote]

I did follow the signal through with a probe and it goes everywhere, the problem is there's no wah sound. I've taken off all the mods and taken the circuit out and wired it directly to jacks without a switch, my voltages are getting close to where they should be but there's still nothing happening.

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[quote name='JackLondon' post='806219' date='Apr 14 2010, 04:35 PM']I did follow the signal through with a probe and it goes everywhere, the problem is there's no wah sound. I've taken off all the mods and taken the circuit out and wired it directly to jacks without a switch, my voltages are getting close to where they should be but there's still nothing happening.[/quote]

I've never worked with these chips before, am not familiar with the circuit, and don't have it in front of me to work on. Having said that, and based off of what you said above, this is my best guess, and this is what I would try:


Take out IC3, and directly connect where pins 11 and 10 were in the socket with a jumper wire. Do the same to pins 9 and 8. Don't worry about any other pins for now.

Run audio through the pedal. The wah effect should now be hard on. If there is still no wah, start by diagnosing the audio filter, which is the top part of the circuit.
If there is a wah sound now, the problem lies either with IC3, or with the control voltage generator, which is the large, bottom portion of the circuit diagram.
Whichever of these two outcomes it is, let me know, and I'll help you the best I can.

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Update on the big red thingy.....

Used it live a few times.
Last time, stage lights and faulty wiring meant that there was hums everywhere.
Not only did my pups not like the dimmers on the lights but something was inducing a hum somewhere in the SFT and Muff circuit. (the small clone was alright)

In trying to solve it i found:
- my SFT gain pot was bust and not working.
- the earthing wire from the input to the bridge on my JV squier was missing (!)
- the power adaptor i was borrowing wasn't regulated, and the power jack didnt fit too well.

To solve it I:
added the wire to my P bass (why dont they earth through the amp's earth, surely that would make more sense?)
replaced the bust pot
replaced the jack out which may have also been giving me the odd open (it had a fight with a soldering iron during the build)
removed the LEDs, who needs them?
removed the battery
bought a new power thingy

test it tommorow!
simplified it inside. removed the battery,

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[quote name='LukeFRC' post='809863' date='Apr 17 2010, 09:18 PM']added the wire to my P bass (why dont they earth through the amp's earth, surely that would make more sense?)[/quote]

To stop you from being electrocuted in case the signal ground goes live for whatever reason, or in the more likely event you touch something else live while holding the strings. If you put a 47nf or 100nF cap between the bridge and the ground, instead of a straight wire, then you should be alright, as the cap will limit the AC current that can flow through -- give you a sharp jolt but nothing that will do any damage.

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I have become obsessed with modding tubescreamer pedals for bass and guitar, this is the little clipping switch I've developed for my Sonic Kitchen Tubes Creamer.

A bit fiddly to solder but a neat little unit that can solder directly onto any overdrive pcb to replace the 2 parallel clipping diodes in the circuit.
This is an ON/OFF/ON switch so when its in on position 1 it shorts out the 2 Si diodes and routes signal thru the LED diodes. In On position 2 it does the reverse.
On the middle OFF position it routes signal thru both sets which knocks the output way down.
The LED distortion is much higher volume raw gain, biting aggressive distortion, you can go from raw crunch to a splatty fuzz.
the Si diodes gives you the conventional Tubescreamer overdrive, much softer sweeter harmonics and lower output that you can compensate for with the volume knob.

Using the same switch and 2 different capacitors instead of the diode pairs, soldered direct to teh switch lugs, you get the great AMZ Phat mod which for me is essential for using the pedal effectively with the bass guitar. The jumper wires then replace the 0.047uF input cap.
On ecap choice remains at 0.047uF for the characteristic tubescreamer mid tone boost, the other can go up to 0.47 or 0.68uF to let a huge load of bass through which, to be honest, sounds fabulous!

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[quote name='escholl' post='809012' date='Apr 16 2010, 10:50 PM']I've never worked with these chips before, am not familiar with the circuit, and don't have it in front of me to work on. Having said that, and based off of what you said above, this is my best guess, and this is what I would try:


Take out IC3, and directly connect where pins 11 and 10 were in the socket with a jumper wire. Do the same to pins 9 and 8. Don't worry about any other pins for now.

Run audio through the pedal. The wah effect should now be hard on. If there is still no wah, start by diagnosing the audio filter, which is the top part of the circuit.
If there is a wah sound now, the problem lies either with IC3, or with the control voltage generator, which is the large, bottom portion of the circuit diagram.
Whichever of these two outcomes it is, let me know, and I'll help you the best I can.[/quote]

Cheers for all the tips, this was however too complicated for me to debug so I had someone sort it out for me, I'm still having problems with my delay and I'm determined to get this working myself, the problem is that most of the stuff found on some effects forums are very much useless because people on there seem to directly jump into the big stuff etc.


On another note does anyone know if I can replace ZL9M3 diode with a 1N4148 ? It's for a wah circuit.

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I think the ZL9M3 is a zener diode - they work with opposite polarity to normal diodes and there will be a threshold voltage with them, so no u can't.

[url="http://www.freeinfosociety.com/electronics/schemview.php?id=351"]http://www.freeinfosociety.com/electronics...view.php?id=351[/url]
Used in the Cry baby wah circuit - any 9.1V Zener diode can be used instead, but not a normal one such as 4001, 4004, 4148, etc.

Edited by Al Heeley
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[quote name='JackLondon' post='818621' date='Apr 25 2010, 10:53 PM']I'm still having problems with my delay and I'm determined to get this working myself[/quote]
If you need/want help, fill me in on the current state of it and I'll try to help as best I can. Not saying you have to, just saying the offer is there. :)

Best of luck getting it working mate!

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[quote name='escholl' post='818791' date='Apr 26 2010, 02:36 AM']If you need/want help, fill me in on the current state of it and I'll try to help as best I can. Not saying you have to, just saying the offer is there. :)

Best of luck getting it working mate![/quote]

Aye, the problem is exactly the same as with other ones, signal goes through the board but no delay, read somewhere that it should have delay on the pin 15 of IC1 but I get nothing. BTW it's Rebote 2 Delay from tonepad.com

Any ideas where to start ? And on top of that any suggestions on books about stuff like that, I bought a book about electronics etc but it's very general and doesn't mention anything about effects and stuff like that.

Cheers
Jack

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[quote name='Al Heeley' post='811875' date='Apr 19 2010, 09:02 PM']I have become obsessed with modding tubescreamer pedals for bass and guitar, this is the little clipping switch I've developed for my Sonic Kitchen Tubes Creamer.

A bit fiddly to solder but a neat little unit that can solder directly onto any overdrive pcb to replace the 2 parallel clipping diodes in the circuit.
This is an ON/OFF/ON switch so when its in on position 1 it shorts out the 2 Si diodes and routes signal thru the LED diodes. In On position 2 it does the reverse.
On the middle OFF position it routes signal thru both sets which knocks the output way down.
The LED distortion is much higher volume raw gain, biting aggressive distortion, you can go from raw crunch to a splatty fuzz.
the Si diodes gives you the conventional Tubescreamer overdrive, much softer sweeter harmonics and lower output that you can compensate for with the volume knob.

Using the same switch and 2 different capacitors instead of the diode pairs, soldered direct to teh switch lugs, you get the great AMZ Phat mod which for me is essential for using the pedal effectively with the bass guitar. The jumper wires then replace the 0.047uF input cap.
On ecap choice remains at 0.047uF for the characteristic tubescreamer mid tone boost, the other can go up to 0.47 or 0.68uF to let a huge load of bass through which, to be honest, sounds fabulous![/quote]

Al, I've noticed that you are etching your own pcb's, interested in doing few for me ?

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[quote name='Al Heeley' post='823331' date='Apr 29 2010, 07:38 PM']i [i]was[/i] jack but since I buggered up the office laserjet printer with blue press-n-peel paper i've had to go back to only really simple ones i can draw by hand with etch resist pen. This sort of limits me to simple fuzz circuits you could build on veroboard.[/quote]

Cool, not to worry, I gues I'll have to have a go myself :) Do you have alink to a good tutorial by any chance ? Preferably one you've tried and works :rolleyes:

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[quote name='JackLondon' post='823340' date='Apr 29 2010, 07:48 PM']Cool, not to worry, I gues I'll have to have a go myself :) Do you have alink to a good tutorial by any chance ? Preferably one you've tried and works :rolleyes:[/quote]

This one's great: [url="http://www.riccibitti.com/pcb/pcb.htm"]http://www.riccibitti.com/pcb/pcb.htm[/url]

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[quote name='JackLondon' post='823464' date='Apr 29 2010, 09:56 PM']I'm afraid that the above isn't for me, I only have a normal ink printer. Any other ideas???[/quote]

You can't really make your own if you don't have a laser printer. As far as I know anyway... there may well be a solution I haven't come across.

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[quote name='gnasher1993' post='823497' date='Apr 29 2010, 10:33 PM']You can't really make your own if you don't have a laser printer. As far as I know anyway... there may well be a solution I haven't come across.[/quote]

As Al mentioned earlier, steady hand and a lot of patience and of course etch resistant pen :)

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and a good magnifier lens - essential! then you need a hot concentrated etch solution as if it takes too long the pen starts to wear off. Good copper board prep beforehand helps give best surface for the pen or the transfers.
There's also decals you can use, rub-on dry decals for pcb's but they are also a huge pain to use.

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