The D.I.Y. FX Pedal Building Thread

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Originally Posted by wokkaboy

hardcore Doc staying up all night, hope you can get some sleep sometime today. Look forward to pics and eventually sound demo's.
Will the other tubes be easy to interchange for a demo ?
The only awkwardness I see with the tube where it is, is adjusting the 2 dials but sure it won't be a problem. Also if you have a massive pedal board if that pedal was at the front you may end up tripping over it ! Would have to have it at the back of the pedal board

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Yep, the tubes are easy to interchange for the demo, all you need to do is remove the shield, then remove the tube, replace it with another one, then put the shield back on, you can even do it while the pedal's powered up since it operates at a low voltage and nothing will get damaged.

I guess you could use a bigger case to house the circuitry in and then the two controls would be easier to get to, I'm already thinking of some mods to the original design, and I might present it as another DIY project, just need to breadboard the circuit to try out the mods and tweak things if necessary.

no worries Doc, so is that how the original Persuader pedal was had the tube on top of the pedal ?

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Originally Posted by wokkaboy

no worries Doc, so is that how the original Persuader pedal was had the tube on top of the pedal ?

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Yep, that's how the original Persuader pedal had the tube situated on the pedal, I can't see why the pedal couldn't be modded to have the tube mounted inside it, but the circuitry would need to be built on a piece of Veroboard to get it to fit.

Here we go, as promised, here are some build process pics I took as I was building my Persuader Tube Distortion pedal:


First thing I did was to mark out the centre for the large mounting hole for the 9-Pin tube socket, this is because the positions of the other mounting holes in the diecast case are based off the position of the Tube socket so that there's enough clearance:

Attachment 12764

Having established the position of the Tube socket, I marked and drilled two smaller holes for the mounting screws that hold the Tube socket in place, I also marked and drilled all the other holes to size:

Attachment 12768

Next, I did a test-fit of the 3mm Blue Led, In/Out sockets and footswitch:

Attachment 12771

Next, I cut the pot-shafts to length and mounted them in the diecast case, I also cut two of the 8-way tagstrips so that they had 5 tags on them, and mounted them plus the single 8-way Tagstrip in the mounted case, I also mounted the black plastic DC in socket in the case, I positioned it near the output socket to ensure that no hum/noise got into the input of the pedal:

Attachment 12772

Next I fitted the two knobs to the pot shafts and checked that there was enough clearance between the Tube socket and the pot knobs:

Attachment 12773

Next thing to do was to remove everything from the case, wipe all the marking out off it, and then start soldering all the parts onto the single 8-way Tagstrip, this is what it looked like after I had finished doing all the soldering:


Attachment 12774


Next I installed all the Pots, Sockets, Led, and Tagstrips back in the case so I could start doing all the wiring-up:

Attachment 12775

I started doing the wiring up by soldering a .1uF/100V cap between one of the tags on the 8-way Tagboard and one of the solder-lugs on the footswitch:

Attachment 12776

Next thing to do was to solder-in some ground wiring and a 22uF/25V cap, I also soldered a piece of red wire to the + terminal on the DC in socket after soldering a black wire from the circuit-grounds to the - terminal on the DC in socket, the extra 220uF/25V cap was soldered between a ground tag on the 8-way Tagstrip and the + terminal on the DC in socket:

Attachment 12777

Next, I soldered-in a 22k/ 1/2 Watt resistor between one of the tags on one of the 5-way Tagstrips and the + terminal of the 3mm Blue Led, this 22k resistor limits the current to the Led so that it doesn't burn out:

Attachment 12778

I also added some orange wire to connect the tip solder-lug of the input socket to one of the solder lugs of the footswitch, I did the same for the output socket except I used a piece of white wire, it makes things a lot easier if you colour-code your wiring up.

So, after soldering in all the wiring and all the other components, this is what the pedal looked like when finished:

Attachment 12785


This is what's called point-to-point wiring since no printed-circuit board is used, the components are simply soldered between two convenient points, lots of old guitar amps from the 40's, 50's, and 60's were built this way, some musicians reckon an amp built point-to-point style sounds better than one built using a PCB, personally I don't really hear much difference, although the point-to-point style of construction does have some advantages.


For those of you interested in hearing what the Persuader actually sounds like, I'm going to record some demo clips shortly, so stay tuned.


Here are the links to the demo clips I recorded, this is what the raw sound of the pedal sounds like:

https://dl.dropboxusercontent.com/u/...der_12AU7A.mp3

https://dl.dropboxusercontent.com/u/...ader_12AT7.mp3

https://dl.dropboxusercontent.com/u/...ader_12AX7.mp3


I'm going to do a small mod to my Persuader pedal that I've just thought of, the 5K Drive pot seems a bit too big so I'm going to try replacing it with a 1K Pot to give a better range of control so that it's not bunched-up at one end of the knob rotation, also I'm going to add a bypass cap from the pot wiper to ground, might record a demo after the mod has been done.

Great job Doc sounds good too. Personal preference was the 12AX7 bu the others may cut through a mix better.
Well done.

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Originally Posted by kimball492

Great job Doc sounds good too. Personal preference was the 12AX7 bu the others may cut through a mix better.
Well done.

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Cheers mate, I liked the tones I got with both the 12AU7A and the 12AX7, the 12AT7 sounded a bit brighter to my ears, I have just tried the pedal out with the mods I thought up, to my ears it seems to sound a bit less gainier at max Drive settings, but the tone is a bit smoother, it still really likes being overdriven with my Rangemaster pedal though, I'll record a demo of the modded pedal a bit later on for those interested.

Of course, you don't necessarily have to stick with using the Persuader pedal with a guitar, you could probably use it on drum loops, etc in a studio.

Okay, here's the demo clip of my modded Persuader pedal, I recorded it and my Rangemaster pedal straight into my Saffire Pro40, into FL Studio, I only used one plugin, an Impulse Response Speaker Cab simulator called NadIR, set to simulate a quad box with Celestion G12's miced up with an SM57, I used the Rangemaster pedal to overdrive the Persuader pedal, the guitar I used was my LP Studio, the Tube installed in the socket is a Ruby 7025SS/12AX7A, first half of the demo is the modded Persuader by itself, set to max Drive, second half is same like the first half but with the Rangemaster switched in, the knob on the Rangemaster was set to about the 2 o clock position, just check out the sound I got:


https://dl.dropboxusercontent.com/u/...angemaster.mp3

that sounds great Doc