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Topics - mjg

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Build Reports / DS-1 clone
« on: January 03, 2018, 02:04:14 AM »
I've finished off the DS-1 clone that I did a PCB for recently.  The PCB worked, so I'm happy with that. :)

The 9 clipping options include a mix of 914 and Bat41 diodes, as well as some power mosfets, LEDs, 4001 diodes and some 1n270s, which make the whole thing very fuzzy.  Most of the options have different sounds, but I can't hear any difference between the few 4001 combinations that I put in. 

The only major issue with this build was my ancient 15 watt soldering iron died part way through.  I ended up ordering a Hakko FX888D station as a replacement and xmas gift to myself.   It was meant to ship overnight... but three days later hadnít left the warehouse.  Turned out that they were waiting on a free gift to include with the order, which was on back order.  Argh.  First world problems.

I wasnít feeling particularly creative when doing the artwork, so it got a generic bad 80s makeover, with tiger print and stencil font decal.

I'm really enjoying the soft touch relay bypass.  There's a little bit of a click sometimes, but overall so much nicer than the 3PDT clunk. 

I've still got a few of these PCBs available for free in the PIF thread:

Open Discussion / What bass guitar pedal used on this song?
« on: October 12, 2017, 03:51:32 PM »
Anyone know what sort of pedal has been used for the bass guitar on this song by Forq?

Almost sounds like a clarinet, it's pretty cool.   (My partner is learning the song, and now she wants the pedal to go with it...)

Build Reports / Sonic Reducer
« on: September 26, 2017, 02:58:57 AM »
This is a Sonic Reducer (version 1.0) from Parasit Studio on perfboard.  I didn't plan it as much as I could have, so ended up with a few jumpers here and there.

It's a fun sounding circuit.  Really gets that 8 bit computer game sound if you dial it in right. 

Graphics done by my kid.  He thought that it sounded like Mario jumping, so hence the theme. 

I've done the top with some laser etched perspex over the decal.  Last build I did with this stuff, it was OK, but that was a cheap enclosure.  This time, the enclosure wasn't so cheap, and the metal was thicker, so the pots didn't have enough thread to tighten the nuts.  I started by counter-sinking the back of the enclosure, then also had to cut away some of the front of the perspex, and also trim the bottom off the knobs.  What a nightmare.  I think I'll have to find some thinner perspex if I do this again, or use longer threaded pots.  3mm perspex is too thick. 

I wanted an arcade style momentary button to go with the theme, so I've put a relay bypass on board as well.  As I've done a lot of Arduino in the past, I went with a ATTiny85 for the controller and programmed the switching in Arduino IDE.  I didn't worry about muting the volume as the relay switches, it seems to be really quiet already.  But I do have 1 extra IO pin on the ATTiny if I want to do the muting code later. 

And totally unplanned - the etched writing on the perspex glows in the dark when the button is lit. 

Guts shots:

And the inside of the enclosure, to try to get a bit more depth for the pot threads  ??? 

Build Reports / The Alpaca Lips
« on: September 02, 2017, 09:44:13 PM »
This one is a 1776 Effects 'Buzz Saw'.  The "Baa" mode made me think of sheep, and it was a slippery slope into alpacas after that.  Photo is one of my mum's alpacas.

I've done an optical switching mechanism on vero for this one, and glowing red eyes for the alpaca - super glued the LEDs on the inside of the enclosure, and did 1mm holes underneath the eyes.   

The top is waterslide decal for the photo and black text, and then a laser engraved perspex over the top.  I got that done at, they give you a $20 discount on your first order, which was more than enough to do 2 x 1590B and 1 x 1590BB plates, and an assortment of washers and things.  The shipping cost to Australia was enough to make it not worth doing very often though.  It's 3mm thick perspex, which made fitting the pots pretty hard.  I had to countersink the inside of the enclosure so there was enough thread poking through to put a nut on. 

Cool sounding fuzz... the two modes give it a nice range of sounds. 

Build Reports / The Mothership
« on: July 31, 2017, 03:46:54 AM »
This one is a Theremin Fuzz from Parasit Studio (thanks Freppo!), with a custom PT2399 echo circuit that I put together (achievement unlocked?)

I found this old Apple Airport base station behind my parentsí filing cabinet a while ago.  It had been faithfully serving up a defunct wifi network for about 5 years since the telephone company technician installed a new wifi router for my parents, and didnít bother turning off the old one.  I decided to give it a better life. 

Rotary switches for the octave selector on the theremin, and another rotary for selecting the theremin, echo, or both chained.  I've put in a small circuit with a few transistors so I can switch both the LEDs on when both effects are running. 

The echo has speed warping and max feedback momentary switches.

The drilling was a bit of a hassle Ė there are no straight surfaces on this thing, so lining up holes was a challenge.  The boards sit off the knobs and switches with some orange juice container plastic that I cut up for the purpose.  And of course after I got everything together, I found that the very middle lug on the stomp switch wasnít quite soldered properly, so had to pull everything out again.

This one took quite a while to get finished Ė itís probably been sitting on the shelf in various states of undress for a few months.  But itís finally finished, and working.  I had to go with shielded wires leading into the Theremin Fuzz, as it really misbehaved if it didnít get a nice clean signal.  The shielded wires seemed to help the tracking. 

Originally I had an optical bypass in there as well, but that seemed to be screwing with the theremin as well, so I pulled it out and went with a plain 3PDT.  I'd probably just wired something wrong. 

Gut shot:

Night shot:

Video demo (about 2 minutes long):

Build Reports / Pine-o-clean tremolo
« on: July 30, 2017, 03:25:49 AM »
I posted a build report the other week about part of my kid's school science project - a tremolo build.  (

Here's the rest of the project - he has built a tremolo using a motor, spring, container, and liquid sloshing around.  There was much science done testing different liquids, and in the end 'Pine-o-clean' was chosen as the tremolo liquid of choice. 

It has two configurations with the container upright wobbling, or horizontal being bounced back and forwards in a pipe.  Amazingly (well, to me anyway) this works out as an almost sine wave tremolo and a square wave, respectively. 

The tremolo has a bit of randomness to it... sometimes the waves come in groups of two or three close together, then with a bit of a gap.  It's a pretty cool sound. 

Example of the waveform coming out of this thing:

He also played around with a solenoid instead of the motor, but that bit isn't finished yet. 

The 'guts':

A 30 second video of it working:

And a 5 minute video if you want more 'science':

Build Reports / That's no moon!
« on: July 13, 2017, 02:39:49 AM »
A Shoot the Moon tremolo build - this one was done by my kid.  This is part of his school science project this year, so he's doing all the work on this one. 

Normally when he helps out with the soldering, I'll select the parts and hand them to him, letting him know "This is R7", etc. 

For this build I left him to it with the board, soldering iron, component list and box of many parts.  He managed pretty well - only one mistake on the build.  He put a 100k resistor in place of a 100R... which took me about half an hour to track down.  Then another half an hour to realise that desoldering the resistor had broken the trace between the top and bottom of the board.   ::)

I also made him do all of the off board wiring (including off board pots) on this build.  Because I'm evil. 

Graphics were also his design.  I had a nice artistic photo of the moon, but once he heard the name of the pedal he went with a Death Star theme.  Waterslide inkjet decal, with some clear spray over. 

Cheap eBay enclosure, which was pretty crap quality (the aluminium had cracks in it!), and finally found a use for some of the giant knobs I accidentally ordered months ago. 

The sound is pretty cool.  The square wave / sine wave setting is especially interesting for his science project, so that's a bonus!

The gut shot shows that the board has had the name scratched off.  It was like that when I bought it, not sure what the story is with that!

Build Reports / No name Fuzz
« on: June 20, 2017, 10:26:31 PM »
This is a Fuzz face variant with a MOSFET in the 2nd transistor spot.  It's a bit insane when you turn the fuzz pot all the way up.  I originally got the schematic for this on 

This is the first pedal that I've built for someone other than a family member.  Achievement unlocked!

My wife's boss wanted a pedal, so he borrowed all of my fuzz pedals, and picked out this one as his favourite, and commissioned me to build one.  I charged for parts plus added a small fee that didn't really cover my time at all.

He also wanted an internal battery - I've not done that for a while, I'd forgotten how much extra wiring is needed to add all the battery switching.   

Nothing fancy with the graphics, he wanted it plain. 

And a photo of my soldering 'helper'

Open Discussion / Tremolo LFO speed ranges?
« on: June 12, 2017, 12:04:41 AM »
Can anyone point me in the direction of a website that has info about typical LFO speed ranges for tremolo pedals?  I could have a guess, but something written down would be good, as this is for a school science project my kid is doing.

Failing that, I'll welcome expert opinions of forum members.  ;)

(I'm trying very hard to not take over the project, it's meant to be his work  ;D )

Build Reports / Vanilla Fudge
« on: May 06, 2017, 09:24:16 PM »
Someone gave me some vanilla fudge in a tin a while back.  My first thought was "Ooh, fudge!" but my second thought was "Ooh, pedal enclosure!".   ???

Figured that the flowery finish would be appreciated by my partner, and she plays bass.  So I've turned it into a 'Bazz Fuss' variant from Runofgroove/Home Wrecker. 

Switchable diodes - a 914 for insane gain and fuzz levels, and a 270 for a more refined sound. 

Drilling the thin metal was exciting as always, and had a few tears that I've managed to cover up with the washers.  The metal is curved, thin, bendy and has embossed flowers.  Not great for drilling precision holes!

Customised the text on the bottom for some fun (and then spent about half an hour trying to convince the printer to print landscape onto small photo paper - argh!)

Not convinced on the knob style at the moment, I might swap it out later.  Maybe white would look better?

Build Reports / Slow Gear clone
« on: May 02, 2017, 05:29:27 PM »
This is from a PCB that I got in the holiday PIF - thanks to Tremster!   

It's a fun pedal to play with.  Works well with the guitar and bass. 

I've used a 25kB pot and 1u capacitor for the attack control.  There seems to be a few different BOMs for this pedal floating around, so I trialled a 100k pot, and a 0.47u cap, didn't make much difference on my setup, so went with the first values. 

Enclosure is the trapezoid Hammond.  Decorations are bike cogs, which I've stuck together and onto the top with PU glue.  That stuff is awesome.  I was skeptical that it would work on metal, but no issues.  Those cogs aren't coming off. 

I had to cut down the pot shafts, and also cut the nuts, so that the knobs would fit on flush with the bike bits. 

Five LEDs in a ring around the switch, under the cogs, so the whole centre bit glows.  Initially had 5 yellow LEDs in there, but made the mistake of assuming I wouldn't need a CLR for that.  Pop go the LEDs.  Only had white ones to replace them with. 

Writing has been done with a rotary tool with a diamond bit.   It's a bit messy ... filled it in with gold nail polish, then sanded off. 

The top of the enclosure has been sanded with 2000 grit wet paper, then polish.  It came up super shiny, which lasted about 3 minutes before it had finger prints all over it.  :)

Oh, and this is what happens when you try to find a nice sunny spot to take photos of the finish.  The cat comes and claims the sun.   ::)

Open Discussion / NSD
« on: April 24, 2017, 08:01:29 PM »
It's New, but really old, Soldering iron Day.

I was visiting my grandmother on the weekend - she's 86.  At the moment she is trying to clean up her garage, as she "doesn't want to be a burden when she's not around any more".  Her words. (For reference, she gave up chopping her own wood with an ax last year).

She ended up giving me a soldering iron that belonged to my granddad.  He died about 25 years back, so the iron is at least that old. Also a tin of flux, which had the price in shillings and pence, which would be pre Australia going to metric.  Probably purchased in the 1960s? Earlier?

Anyway, this iron is a monster. 100 watts. The tip is about the size of my finger. Not sure what I'll be able to use it for, for fear of setting things on fire!  The solder was a bar of metal the thickness of my finger.  Enough to drown ICs in a single pass.

There was also a cupboard full of plans for building your own submarine, so maybe that's what a massive soldering iron is good for.  ;)

I'll post some pics once I get them off the camera.

Build Reports / Glam
« on: April 11, 2017, 03:34:17 AM »
Finished off a Madbean 'Glam' chorus today. 

This one is the first pedal that my kid has done all the soldering on.  He's helped out with resistors and caps in the past, but this one he did everything on the board, and the jacks.  It fired up first time, which was a relief! 

He turned 10 years old last week... where the hell did that time go? 

The 3PDT board is connected using PCB header sockets.  Worked really well, as long as you don't mind the stomp switch being right up against the bottom of the main board.  Makes for an easy assembly as you can just push the switch daughter board in to place.   

Enclosure was done with a vintage typewriter, onto sticky back plastic, with some clear gloss sprayed over the top.  Any typos are the genuine article... no delete key on that thing.  No copy/paste either.   :P

Only regret is that I didn't quite get the typing lined up properly, I think if the word "Glam" was just below the LED rather than half underneath it, that would be nicer.  Oh well. 

The quote is actually a Roxette album name.  Shameful I know.  But it popped into my head and I thought it worked well... only realised later where I must have got it from. 

The effect sounds good - it does give quite a volume boost, as the build doc says it might.  I've not experimented with R9 to see if I can fix that, but I don't mind the boost.  The PT2399 that I used was a cheap eBay purchase... it is a bit noisy and has all sorts of funky junk going on quietly in the background.  I will probably swap in a few others to see if I can get one that's a bit nicer. 

Also works quite well with the bass guitar.   Some nice ringing sort of tones with the knobs up full. 

Build Reports / Sharkfin
« on: April 01, 2017, 03:31:53 AM »
Finally closed up a Sharkfin build today.  This one has been kicking my butt a bit, trying to figure out why it was making an ugly ticking noise in bypass mode.  Changing to shielded wires for the jacks, and running them direct to the 3PDT seems to have helped, and I also had to run the ground wire down from the rate LED to reduce the ticking noise.  All very strange, and the guts now don't look as neat, but it sounds OK. 

This is one of those weird sounding pedals that I like to build, then think "but when would I ever actually use this?".  The 'sample hold' sounds awesome... but I can't think of a song that it works with. 

The filter section also sounds really good.  You can get all sorts of sounds out of it depending on the settings.  Also sounds good with bass.  Very funky.  But I was rolling on the floor when we discovered the magical setting where bass guitar started to sound like really bad bathroom issues.  Hilarious. 

Enclosure is a Hammond red, which I've sprayed white on the top.  Then an inkjet sticky label.  The photo is one I took... they are beautiful looking creatures (when there is 5cm of plastic between you and them). 

I couldn't handle that some of the pots I used were different shaft lengths - so took to them with an angle grinder to even them up.  Tayda knobs on top. 

I've used a bi-colour LED - blue for effect on, and red flashes for the rate. 

Tech Help - Projects Page / Sharkfin - this one weird issue...
« on: March 31, 2017, 04:34:58 PM »
I've recently finished a Sharkfin (2015) build, and it works great, except for a niggling little issue or two.  I can work around them, but I'm curious as to the 'why' of what is going wrong. 

I wired it up with the top mounted connections, and a 3PDT board at the bottom. 

Problem 1) Works fine with the effect engaged, but when in bypass, there is a high pitch squeal noise over the signal. 

I fixed this by replacing the 7660SCPAZ with a LT1054CP with pin 1 lifted.  The squeal went away in bypass mode. 

Problem 2) Works fine with effect engaged, but when in bypass, there was a 'tick tick tick' in time with the speed of the effect. 

I tried a few things to fix this. 

 - I disconnected one of the grounding pins on the 3PDT board, just to check that wasn't an issue - didn't help. 
 - I removed the top mounted jack connections, and instead used some shielded wires to connect the jacks to the 3PDT at the bottom.  Disconnected the 'I' and 'O' wires from the board to the 3PDT board.  This has fixed the problem. 

So it seems that using the top mount connections on the board can somehow cause interference with the bypass signal.  This had me scratching my head for a while.  Is the signal on the PCB passing too close to something and getting interference?

Problem 3)  Effect works fine with the 'Rate' LED connected on the board in situ.  I decided I wanted to have the rate LED at the bottom of the enclosure, so ran a single wire from the +ve connection for the LED, down to an LED at the bottom of the enclosure, and used the ground connection from the 3PDT. 

The 'tick tick tick' noise is now back, when the effect is engaged, but it's more of a mellow 'wump wump wump' noise now.  It changes with the speed of the effect. 

Playing around with shielded wires didn't have much luck, until I finally tried using the ground connection from the LED near the top of the board, rather than the ground connection near the bottom.  The noise went away. 

So I know how to fix the problem now - run a ground wire for the LED.  But what I want to know is why this is happening.  Is it some strange ground loop?  And now that I've narrowed it down to a grounding issue, I'm guessing that the problem (2) above was the same thing - changing from the ground at the top of the board to the ground at the 3PDT seems to fix the problem. 

I've checked the ground for the LED and the ground on the 3PDT - they have 0.03 ohms resistance between them, which seems pretty normal. 

I'll post IC voltages and pictures of the board in a minute...

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