Time for a new pedal build! This time I’m trying to reproduce the mighty Analogue Man King of Tone.

I’ll be building the dual circuit cascaded version. The first stage with the more moderate 100k gain pot, the second with the angrier 250k gain pot. Each stage will be switched in and out separately with a true bypass switch. With both off it’ll bypass entirely, with only one on it’ll act as a straight overdrive with the second bypassed. With both on it’ll stack the first stage into the second stage.

I’ll be moving the dip switches to the front of the box to allow tweaking of the clipping on the fly but other than that will be leaving the controls pretty standard, with three pots on each side. I'll be using the 1n4001 and 1n914 as clipping diodes because they are lot easier to source than the originals and seem to give very similar results.

The only real mod that I’m making is stealing the power supply circuit from the Klon (well… just the voltage doubler really) so that the pedal can either be driven at 9V or at 18V, with a selector switch on the inside.

Here is the working schematic that I have put together, it may be refined slightly during the build (apologies for the quality, just can't get schematics.com to export an image today). I’m planning on doing this as another veroboard build and am hoping to get it into a standard 1590BB box. The layout and veroboard planning will be my next challenge.

I have also put together a parts list and should be placing my order from Mantech this afternoon. With a bit of luck it’ll arrive late this week or early next and I’ll start putting it together in my copious free time. ?

You mean its isnt finished yet? Booooh

?

guidothepimmp :-P

I've done a rough and ready layout of the pedal so that I can estimate the amount of space I have available for the circuit board.

There are a lot of controls in this box and although I can hopefully stack the jacks and pots above each other, the circuit board is too deep so it has to have it's own footprint. With this layout the circuit board can be 50x63mm, which isn't massive but I'm hoping I can make it work. If not, I have two options.
1) split the power supply off and make a plan with it (possibly move the power jack to one side and mount it next to the jack on the back wall).
2) move to a deeper box where I can have the circuit below the pots.

I noticed too late that I forgot to add the toggles to this model I'm not too worried though because I think I'll be able to get them in next to the LEDs... this is going to be a tight build!

I’ve put together a circuit layout and I believe that I’ll get it all into the box. Frankly it could do with a second revision… but it’s not going to get one. ?

One thing that is abundantly clear is there are a LOT of off-board components… a lot. There are two essentially identical circuits, each of which has a foot switch, an LED, two toggle switches and 3 pots! Putting this together is going to be… fun.

I’m still hopeful that the electronics I ordered from Mantech will arrive this week so I can start soldering over the weekend. I’m planning to go past Communica this afternoon to pick up the enclosure and jacks and may even make a start on the drilling tomorrow.

I’m going to try to 3d print a jig so that I can get the holes nicely lined up this time (the Stormsquatch isn’t fantastic). It’s the first time I’ll use a jig so I’m shooting from the hip but the general idea is to print something that can fit snuggly over the enclosure so that it will stay in place and then to make all holes in the jig 4mm. I will then work them up to their final size using a step drill, which is pretty good at keeping its centre… holding thumbs, metal work really isn’t my forte.

Nice! this looks like it's going to be a fun one.

Yeti I will then work them up to their final size using a step drill

Pro tip right there- they're not cheap but step drills make such clean cuts in pedal enclosures, and don't grip and spin the enclosure around like a twist drill does

peterleroux Pro tip right there- they're not cheap but step drills make such clean cuts in pedal enclosures, and don't grip and spin the enclosure around like a twist drill does

truth!

Yeti If anyone is interested, my issue with the models was getting the normals right on the various surfaces. It’s not something I’ve had to pay attention to in the past so wasn’t really aware of it.

SketchUp is pretty rubbish at keeping track of normals on it's own, but it's quick to fix with the 'display shaded using all same' blue/white display mode and the 'reverse faces' and 'orient faces' commands. But unfortunately it does slow down production for 3d printing

peterleroux so I’m learning. It’s convenient for basic layouts like this but if I need to design something more precise I’ll probably teach myself fusion.

As it happens I made a mess of my model for the 1590BB when I made it a few month ago and my jigs don’t fit... busy printing the update now.

I made some 'close enough is good enough' models of the RS Components equivalents of the 1590B and 1590BB- https://3dwarehouse.sketchup.com/collection/9d97daa6ae31e93336ba97f1da9abaeb/Stompbox-components

Thanks, those will be useful.

Well the metal work is done.

The splitter and AB/Y pedals are ready to be wired up. The only change is that I have a two pole sub mini toggle I’ll be using in the AB/Y so that I can switch the LEDs too.

The 3d printed template/jig worked well but wasn’t an unmitigated success. After the 3rd print didn’t quite fit (clearance wasn’t quite high enough) I decided to just live with the issue and start drilling. Because of this, there was a small gap between the plastic and metal, which caused slight inaccuracies and trapped shavings. Fortunately it didn’t seem to scratch the paint. Secondly, I had to tape them in place and on the back template I made the mistake of taping over one of the holes, which means I ended up drilling it a mm or two off… as it turns out this got swallowed by a bigger mistake when I drilled that hole to 12mm instead of 10mm :/ but I’ll deal with that with washers.

One thing is for sure, despite the small issues, it definitely made the metal work quicker, easier and more accurate. I’ll definitely use the technique next time, although I’ll probably refine the model slightly first.

After I’d finished drilling I did a test fit of the components I’ve got. Unfortunately there were a couple of issue.
1) It turns out I bought mini toggles rather than sub-mini, these should be easy enough to pick up.
2) The two volume pots and the second circuit’s gain pot are too large and I can’t get the jacks in past them. Unfortunately this could be a bigger issue because I haven’t had a lot of luck getting low profile pots in the past, will have to hunt around.

Despite the issues I’m going to go ahead with the build in the meantime. Tonight I aim to wire up the splitter and A/B/Y and replace the gain pot in my Stormsquatch, which is giving trouble. After that I need to cut the veroboard to size and the build the board itself, which will take a good few hours. Then I have a good few loose components to wire before I get to these… so with a bit of luck I’ll be able to source them before I need them.

I've finished with the splitter and A/B and they are working nicely. The were a bit on the fiddly side so took longer than I'd hoped so I didn't get to fixing the klone. I'll try to look at it in the morning.

I just realised that I didn't post my progress after the weekend.

Circuit board is all done. ?
The board itself is relatively tidy but all them off-board wires! O.o This is definitely a build that would benefit from an integrated PCB design.
I'm still waiting for some lower profile pots to arrive (really hoping to get them tomorrow) but I may take a chance and do some assembly before they arrive.

Out of interest, I kept a vague eye on clock while building this board and the time it took was roughly as follows:
Prep work (picking parts, cutting board to size, etc.) - 1 hour
Laying out large components (ICs, trim pots, polarised caps), adding jumpers and bulk of track cutting - 1 hour
Adding resistors and remainder of track cutting - 1.5 hours
Adding ceramic caps - 0.5 hours
* Adding switch and off board wires... 2 hours!

So about 6 hours in total, almost 1/3 of which was handling the off board nonsense... and that's just one side of it. I still need cut those wires to length and attach the them to the controls and plugs.

Right,I spent around two hours this evening and achieved the following:
Stuck down pads to isolate the board from the box
Removed the pots that are too large and need to be replaced
Installed the input and output jacks
Wired the input/output jacks to the foot switches
Wired the LEDs to the foot switches
Connected the clipping diodes and wired them to the toggle switches

Not exactly vast amounts of progress but that is the nature of offboard wiring.

I have now gone as far as I can go without adding the board, so that's what I will do tomorrow. Broad ideal is to wire the switches first, then the pots that are in place, then the jacks... and then wait for the outstanding pot. I'll probably leave the power for last as that is going right over the top (although I may still unsolder those wires and add longer ones so I can run them neatly round the side). The plan is to clip those wires as short as I dare before soldering them to the components so the end result won't be quite such a mess... I hope.

Another hour and a half down and I've taken the pedal as far as I can for the moment. My lower profile volume and gain pots should arrive tomorrow but since I haven't received a shipping notification I'm not holding my breath. It was probably a little fool hardy to go this far without them but I'm getting impatient.

Overall it's quite a mess of wires but that is fairly inevitable given the nature of the build. If I do another build with lots of off board components I'll pay more attention to their location when doing the board layout to minimise the amount of crossing (take a look at the blue and yellow wires flying all the way from the bottom to the top... those are the gain pot, which is early in the signal chain... and hence at the bottom of the board).

I'm really really hoping that this thing just works first time. Debugging this beast will be an absolute nightmare and any corrections under the board will require pulling every component out of the box because the board is more or less suspended by those wires. I did pick up that one of the wires to the clipping diodes in the right hand circuit (left hand once the pedal is right way up) is a touch loose and probably doesn't have a decent electrical connection. It was late enough in the evening that I would have needed to strip the entire pedal anyway, so I've left it for the moment. The pedal will work 90% without it so I can complete the build and come back to it if necessary. One of the nice things about this build is that there are two identical circuits, so unless I've made the same mistake on both (or on something common like the power supply) I'll have a working version for reference.

Assuming that everything works I've probably got about 20 minutes of work left on this... so if those components do arrive tomorrow I should have it done in time for the garage days on Saturday.

Last components just arrived. ?

Had an hour and decided to get the last components in... Turned it on and... Nothing. Not particularly surprising really. The problem is almost certainly with the power supply since the voltage over the input is in the order of 60mV... So I suspect that I've got the polarity on one of the diodes wrong.
Unfortunately this means that it won't be ready for garage days tomorrow... But that was always ambitious.

The real problem is that I'm going to have to strip the entire enclosure to get to the circuit... And the really annoying part is that I could totally have built the power supply first and tested that properly... But I was in a hurry. :-P

So I've finally had an hour to do some debugging... looks like I've got a short inside one of the foot switches of all things. With a bit of luck I'll be picking up a replacement tomorrow.