Gentlemen, don your deerstalkers - the game is afoot!

[duck_arse]

indeed yes, cut between pins 1 and 8, and single throw that switch. is the steam train the Mallard?

[moid]

Wow! Loud you say? Well that made both my son and I jump when we flipped that switch Who ever would've thought that a 46dB boost might be a bit too loud? Well Duck, in case you didn't hear the soundwave reaching you around the globe; Krakatoa style, I can confirm that removing that cable will certainly give my audiologist something to look at next month!

My wife laughed and said Mallard? Puffing Billy is more like it!

Thanks very much for your help (once again); I told my friend the pedal works and he's really excited... now onto making another one for my son and get the artwork done for my friend's pedal (apparently it needs a painting of Boba Fett on it because he's got a Boba Fett head guitar knob to go on the pot, so I need to paint a Boba Fett body to go along with it)... this is going to stretch my artistic skills I think!

I'll make a revised layout for the thread soon in case anyone else ever wants to make this circuit.

[duck_arse]

moidy, if you want something in between the two extremes, you can add series resistance between the pins. if'n youse gots a centre off toggle, you can have kettle in the middle, mallard to one side and puffing billy to the other. I dunno what value resistor you'd want, try 2k2 to 1k5 for starts.

connect it like this [I think I've named the switch-ends barse ackwards]:

[moid]

Thanks yer duckness, the 'tiny bit of too much' volume issue is easily solved by turning the volume pot down (you just have to remember to not have the volume on maximum when you switch from 26dB to 46dB... which is probably obvious if I was to think about it!). I don't have any centre off switches from what I can see - they say On / On (& On & On & On...)

But wait! I have a new problem (or a question anyway). Because I was so excited at making this pedal work I built my son a copy of it today, but he asked for tone knob on it, so I used the SWTC2 (I'd used it before on a delay pedal and it worked really well there) so because I felt so sure everything would be fine, I built the SWTC2 into the circuit without breadboarding it first... because that's the kind of guy I am! Rugged, individualistic, stupid etc

Well the circuit works (haven't boxed it yet) but the addition of the SWTC2 totally removes the asymmetric clipping the original circuit had - it's now a very clean boost with no clipping and a symmetric waveform. The SWTC works - it changes the tone of the sound really well, but it appears to have removed the character of the original circuit. If it's not too much to ask, could the original circuit have a tone control without ruining the asymmetric clipping? If not I will play the circuit to my son tomorrow morning (it is of course midnight here, always the best time to build an effects pedal) and see whether he likes it or not (I suspect not) and I could just snip the tone pot and probably the two resistors and capacitors from the SWTC and the circuit would be a straight version of what I had before and I'll count this as another lesson learned about not doing silly things to circuits without breadboarding first.

I know you like pretty pictures so I drew some things for you - the vero is what I actually made; I think the schematic is correct from that.

Hmm with a bit of jiggery-pokery (and a side serving of malarkey) I suppose I could put the SWTC2 on a switch to switch in and out of the circuit... maybe I'll wait to see if my son prefers the circuit without the tone control or not...

[duck_arse]

yer last circuit has gorn back to the bad old days, that switch has gon rong agin. as for tone, that stuff is beyond me. I'm pretty sure you can implement some tone control using those extra pins on the 386, but I haven't seen anyone do it as yet.

[moid]

Thanks! The switch seems to work though? Or maybe it's the way I drew it that is wrong? Anyways, I made a solution - after my son tested the circuit this morning and said he wanted the original tone, but wouldn't mind the option for a clean boost with tone control I re wired things to have an additional SPDT switch - one throw is the original circuit, the other throw is the clean boost with tone control. The inside of the pedal is going to look like a multicoloured spaghetti explosion, but who cases if it works! Now to work out where to start drilling holes...

[rutabaga bob]

Shoot.  As a guy late to the game (er...thread)...I like the original unit.  There is more than one 386-based dirt pedal around; sonic weirdness has its place, too.

[anotherjim]

I prefer the Puffing Billy concept...

Note the asymmetric output tone stack. What isn't apparent is the boost mode obtained by screwing down the safety valve. Yes, it has valves.

And please don't say train when you mean locomotive!

Bob, Moid usually goes for weird. I too am surprised he is content with a mere distortion.

[moid]

Shoot.  As a guy late to the game (er...thread)...I like the original unit.  There is more than one 386-based dirt pedal around; sonic weirdness has its place, too.

In that case I'll draw out a perf board layout of the whole circuit if you like (while I've still got it on my desk). I agree, sonic weirdness is often good, but in this case I've tried playing with the pedal but can't get it to play what I want, when I want it, if that makes sense - it has a mind of its own and the oscillations are not controllable. I'm not sure what triggers them - I thought it would be envelope based, but often it seems to be random and sometimes it gets stuck on one sound and plays it repeatedly even when the dry signal is doing something else... and if you feed it a chord it gets very confused! Feel free to have fun with it

I prefer the Puffing Billy concept...

Note the asymmetric output tone stack. What isn't apparent is the boost mode obtained by screwing down the safety valve. Yes, it has valves.

And please don't say train when you mean locomotive!

I'm impressed with the level of dirt that the above circuit has! Plus that all important envelope triggered oscillating whistle sound - it really gets the crowd's attention on the chorus!

Bob, Moid usually goes for weird. I too am surprised he is content with a mere distortion.

Don't worry anotherjim, I still prefer the weird - these two pedals are for other people; one for a friend who plays what I can only describe as 'normal' music, and the other is for my son who just likes putting an acoustic guitar through it... which it does sound quite good, but I think it needs a blend between wet and dry; I'm not suggesting that though, I don't want to rebuild this thing anymore! I'm moving onto my next project; the Sentinel made by arph on this forum. I heard a couple of videos with this in it and it sounds like my sort of thing

[duck_arse]

but surely the train makes noise, as does the locomotive that pulls it.


moid moid moid, we have all done you a terrible dis-service, and failed in our responsibillities. none of us, not one, has pointed out that you don't have an output DC blocking cap in any of your circuits thus far. ohh, the shame! you need one between the output pin and whatever you have following, whether it's a volume pot or a tone controll. the addition of the required cap might bring your whole sound undone, or might be the answer to your requirements, but youse gots tos has its, any way it goes.


yer switch drawing on the last went back to wrong, however you actually had it wired. and, when your circuit drawings inevitably escape the surly bounds of this thread, they will benefit from version numberings showing somewheres upon.

thanks for the pic, but 4000x4000 for an avatar is a little lavish, methunks.

[rutabaga bob]

Moid:  the whole-thing perf would be wonderful!

[moid]

Hello rutabaga bob, I hope the below works for you - if you need to query any of it, build it quickly and ask; I have to give the original pedal back soon. I have drawn the pedal as it is (it was made on perfboard) so I hope I've done this correctly; it's the first time I've ever tried to draw a perf layout so do ask if it doesn't make sense.



Yer duckness! I will reply soon, I got volunteered into helping with a lot of DIY at my mother in law's house and I'm knackered (have another day or so of work to go) so will make some new drawings and ask questions then!

Edit: I see you found the make small button for that photo

[rutabaga bob]

Thanks!  Will check it out!  👍
Weird that a company would build a commercial product on perf.

[duck_arse]

martin - not a button, hours of work in gimp. also, your led is backwards in yer last. flat on case goes to more negative when you wish light to issue forth.

[rutabaga bob]

Just starting to look at this.  Noticed your output jack ground...isn't grounded.  Will ask questions if they arise.  Larry

Edit: 1N4148 at pins 3 to 5: positive end to ground as shown is correct?

[moid]

martin - not a button, hours of work in gimp. also, your led is backwards in yer last. flat on case goes to more negative when you wish light to issue forth.

Hmmm that sounds important when in regards to illumination Thanks, I wasn't sure what way round to display the flat side of the LED and I couldn't find anything online to explain what way was best - I'll fix that soon!

Just starting to look at this.  Noticed your output jack ground...isn't grounded.  Will ask questions if they arise.  Larry

Edit: 1N4148 at pins 3 to 5: positive end to ground as shown is correct?

Sorry about the slow reply, I (hopefully) finished creating a wildlife pond with my son today and I am knackered! The weird output jack ground to lug 1 of the volume pot - that is what the original circuit has. It looks odd to me too, but it seems to work, so who knows?

1N4148 has the stripe end connected to pin 3 and the other end to pin 5

Thanks!  Will check it out!  👍
Weird that a company would build a commercial product on perf.

I think they were a very small company indeed! It did make tracing the circuit a lot easier for me, so I'm not going to complain, although the terribly thin wiring inside the enclosure is more 'boutique' than reliable... the perfboard and it's parts are partially held together by hot glue!

[moid]

Hi everyone



Here's a ?final? schematic (with hopefully a DC blocking cap in the right place and of the right value - there seems to be quite a range of values for this cap when I look online, so I went with what seemed a common one to me? - Duck, is this right?).

Except I now have a new problem... having built the pedal, made a lovely job of the inside and outside, I was playing it against the original and I noticed that on the original pedal, even when the oscillation part of the circuit is set to be off (blend at minimum) there is still a bit of the oscillation noise creeping in when I play at loud volumes... so I think that part of what my friend likes about the circuit is that gritty edge to the notes - as the clean notes fade away you can hear a distorted oscillation underneath... I might be about to cry; I can't believe I didn't hear this or notice it before... I may have to figure out how to get the oscillation circuit in there with the three pots that control it somehow inside and set to whatever setting it is he likes... hmmm after writing this and recording a video (see below if you want to hear the circuit in action) my friend said he'd like to try the pedal as it is in his board and see what happens... so I've had to return both pedals (sorry Rutabaga Bob, I hope you got your version built OK) and we'll wait to see what happens... if I do need to build the entire circuit I have a feeling it will have to be on perf board; when I started trying to design it on vero it got rather large for the enclosure.

Pedal demo - original and my clone

Some pictures:
Circuit for my son - this used a pouring technique of multiple layers of dilute acrylic paint and copolymer emulsion - quite chaotic and messy, but fun to make!



This is the underside

Circuit for my friend, the artwork is a digital painting I made that I based on another artist's work (basically I stole the pose and character design, and then adjusted it and totally repainted it - the background is mine). Printed onto sticker paper and applied to the enclosure. I really don't like sticker paper, it never cuts like I want it too and it is fiddly! The missing knob will be filled by a Boba Fett / Mandalorian guitar knob my friend has, which should be similar to the helmet I've painted, albeit somewhat larger.



First time I've made a top mounted pedal; what a pain they are!



Thanks everyone with all the help and advice so far!

edit: My friend sent me a photo of the pedal with the custom knob on it:

[rutabaga bob]

Very nice-looking builds!  Certainly puts ME to shame!

I made a layout and built a board according to what you posted earlier, with the addition of a .1uF cap just before the blend pot.  Haven't tried it out yet.  Hope it works like the original effect.

[duck_arse]

that knob is hilarious. I thought it had gone all wrong in the knobless pics, but now I see it. and yes, might as well be 1uF, it's in the right place.

I don't know the 4046 at all, and I can't hear anything in your vid except the whines of this crappy lappy, but it's possible you were getting unwanted digital feedthrough from the 4046 coupling into the output of that version.

[anotherjim]

That type of blend control pot can't silence the unwanted side. You can disable a 4046 with a switch to pin 5 but you can get away without it.

The 4046 VCO should drop down to subsonic speed when the signal on pin14 stops and that's effectively silent. I think that diode is part of a noise gate and I do wonder if the other diode to pin3 shouldn't be in reverse across the one already going to pin14 and pin 4 directly links to pin 3. The 386 output self biases to 1/2 supply volts. By coincidence, the 4046 signal input is also biased to 1/2 supply volts. So the 386 output would have no effect except when the signal out of it swings above or below a diode volt drop. Simple noise gate.
Pin4 is the VCO output going thru a cap to the blend pot. Pin 4 should also link to pin3 which is the clever bit.
Pins5&6 have a cap between them. That's the oscillator timing which works with the resistor on pin 11 with the pitch pot to 0v.
Pin 2 is the output of the brain that works out if the signal into pin14 is the same frequency as the VCO into pin3. It goes thru the Depth pot to pin9 which is the VCO control voltage input. A cap is added to smooth out the control corrections from the brain together with the resistance of the Depth pot.
If the input signal stops, then the brain thinks it's running the VCO too fast, so it tries to drop the VCO frequency control volts to match which it can't do more than letting it go all the way to 0v. The VCO frequency becomes glacial - you might hear a tick occasionally as it toggles.