Experimental Delay & AmpMod from Noise Workshop

[moid]

D'oh yes paper, I remember that stuff, I used to use it all the time I'll try to start this tomorrow. Some good news - I got my audio probe out this evening and was about to start testing the circuit to see where I screwed up when the whole thing suddenly came back to life I have no idea why. I have noticed that at times it seems to lose its ability to generate delays but I'm hoping that's because it is a mass of cables and isn't protected by a box yet, so hopefully it's randomly shorting out because of this and not because the pt2399 is locking up. I changed c13 to a switch that has 6 lugs (not sure what this is called, probably a DPDT?) and I put a 10nF on one set of lugs, a 100nF on the middle set and a 220nF on the third set. Values below 10nF didn't seem to make an audible difference. 220nF is softer than 10nF, and the repeats fade more. I tried a 1uF and it only gave me one repeat regardless of the feedback setting but then it turned into a fading blast of sound that the circuit seemed unable to play over so I gave up with going that high. I might try a capacitor in the 400nF range; I think I have some somewhere just in case that works, but if not 220nF is good. The effect is most noticeable when the modulation is low, and it makes another 'sound' for the pedal. I'll keep that one, thanks for suggesting the switch technique.

That's a fabulous chord Just two more and you could form a punk band! Thanks for recording that, you've got a cool weird vibrato effect going on that I like! Especially when it sounds like a really slow phaser, that's definitely something I'd like. Do you need to adjust the knobs to get the pitch to warp or does this happen as the result of how hard you are playing? If it works like that I'd love to see how to make it.

[duck_arse]

like paper, it's an envelope.

you'll get used to that. no, all auto warp, the whole point of everything, all the time. has an up/down switch, I edited out most of the madness in that clip. I don't know where the constant little wibbles come from, or how to control them, but any "spill" effects probably comes from envelope ripple, something we usually try and avoid.

I have drawn up that (phaser/viber) circuit for posting very soon, the envelope I used is part of that. it can be added to anything with a sweepable resistor, I guess.

I looked back through some other circuits, and the hamlet has a tone control, based at or near our C13. those other circuits have a slightly different filtering regime as well, but you might some some hints from that. and, the circuits by merlin (greenteeth, smalltime) also show how to do anti-lock-up, if needed.

it's an awful chord, I am tired of hearing it. I'm looking for another to abuse learn ruin.

[moid]

I've had a go at my first schematic. Most of it is copied from Knutolai's schematic, but I've tried to add in my changes as well. The weird box thing with capacitors C12-C14 in it is a DPDT switch; I have no idea how to draw that in schematic form. Once you draw your phaser / viber circuit would you please mind explaining where it connects to my circuit? Don't worry about uncontrollable sounds, they can add to the madness Presumably this is an effect I can blend into the main sound? Once I've seen your circuit I can see how many extra pots I need and what size box I can squeeze this into

I hope the drawing isn't too bad.

[moid]

I have drawn up that (phaser/viber) circuit for posting very soon, the envelope I used is part of that. it can be added to anything with a sweepable resistor, I guess.

I was thinking because I realised this could be something I've always wanted - I'd love a pot that could be used to slowly sweep (automated) between two different signals - so imagine a fuzz on one audio line and a flanger on another audio line and your circuit would slowly sweep backwards and forwards between both? Because that would be awesomely useful to me! Even sweeping between two different fuzzes, if it could be done slowly would make for a really interesting effect (I'd also like to do it with a high pass filter to make a track become somewhat lofi then slowly fade back to normal sound and repeat). I'm excited

I looked back through some other circuits, and the hamlet has a tone control, based at or near our C13. those other circuits have a slightly different filtering regime as well, but you might some some hints from that. and, the circuits by merlin (greenteeth, smalltime) also show how to do anti-lock-up, if needed.

Thanks for the hints - I looked at both the greenteeth and the smalltime circuits because the pt2399 kept locking up today I can bring it back to life by touching the vero board in random places until it wakes up, but that's not a great solution! According to the smalltime circuit a 1K resistor in series with the delay pot should fix this

http://www.valvewizard.co.uk/smalltime.html

And I think the circuit already has one at R1 in the schematic - or is that wrong? (I guess it's not working if it is) Hmmm although Merlin links it to pin 4 of the pt2399, but that also goes to ground so perhaps its position is not vital?

The technique Merlin uses to fix the same issue on the Greenteeth is much more complex and I'm not sure if it will affect the length of the delays (I might not have understood that bit)

I guess I need to look at the Greenteeth solution? In which case I'd better order some BC337s, I don't own any of those

Another question to which there might not be a solution - the pedal generates a huge amount of hiss, even when nothing is playing through it. Is there anyway to calm that down, or is that a property of it not being boxed yet?

Thanks for your help, I hope you had a good weekend.

[duck_arse]

weekends? bah! who needs em?

I'll havva closer squint at your circuit soonest, try and work out that bass pot. as for BC337, ANY npn will do there, it is just to switch, in - out. at start-up, it allows the PT2399 to see a larger resistance, so it won't start with a lock-up, then after a short period, it shorts the resistor, so the user can get at the faster/shorter delays. once it has turned on, it stays on until power-off.

once gndA and gndD are connected to GND, it doesn't matter where your other gnd connections are/go, because they are all the same. you might try upping the value of that 1k resistor, cause there seems little use to the fastest end of the delay pot, to my ears (cloth, dirty).

noise. there are ways, but the name of this particular circuit is a hint. the PT80 for inst, uses a compressor chip. BBD's near allays use pre- and de-emphasis in their signal chain. I've been musing about more hacking at the enveloper, with maybe (rectified) delayed signal added, and an lfo? and with proper input buffer and output mixer. and the delay pot replaced by a vactrol, and some noise reduction. musing, yes .....

and as for your panner, it could be done with a pair of vactrols, with anti-phase leds driven by an lfo. easy-peasy. ish. on the BB, at least.

[Kipper4]

"and as for your panner, it could be done with a pair of vactrols, with anti-phase leds driven by an lfo. easy-peasy. ish. one the BB, at least."

Ouh ouh Mr Beesley.
Now that sounds like a project I could have a go at.......

[duck_arse]

bosh. it's Beazley, by the way, like in John Cooper Clarke.

[anotherjim]

I'm obviously way behind with this -  but what, may I ask, does the green LED do on the PT2399 pin 7?

[Kipper4]

Cooper Clarke got to the Antipodes.

Mr Beazley. What tv series was that from?

[Kipper4]

Not Hijacking.

Was it the hair bear bunch?

[duck_arse]

Mr. Beazley was from "a family affair" (w/ Brian Kieth). hijacking. and not Mr, Street. I saw JCC here twice. (he didn't see me.)

Jim - the green led is included as a clipping limiter thing. I think it's one of Jon Patton's. (hamlet, again.)

[moid]

weekends? bah! who needs em?

I salute your bravery and dedication

I'll havva closer squint at your circuit soonest, try and work out that bass pot. as for BC337, ANY npn will do there, it is just to switch, in - out. at start-up, it allows the PT2399 to see a larger resistance, so it won't start with a lock-up, then after a short period, it shorts the resistor, so the user can get at the faster/shorter delays. once it has turned on, it stays on until power-off.

Thanks, I didn't know that (and I should've checked this thread before ordering some BC337's... d'oh! At least they are cheap)

once gndA and gndD are connected to GND, it doesn't matter where your other gnd connections are/go, because they are all the same. you might try upping the value of that 1k resistor, cause there seems little use to the fastest end of the delay pot, to my ears (cloth, dirty).

OK, I'll try that first... there's nothing wrong with dirty cloth ears, as long as they don't go floppy! Is cloth ears an Australian expression by the way? The only person I've ever heard say that is my father and he's from Hartlepool (North of England).

noise. there are ways, but the name of this particular circuit is a hint. the PT80 for inst, uses a compressor chip. BBD's near allays use pre- and de-emphasis in their signal chain. I've been musing about more hacking at the enveloper, with maybe (rectified) delayed signal added, and an lfo? and with proper input buffer and output mixer. and the delay pot replaced by a vactrol, and some noise reduction. musing, yes .....

Thanks for warning me, in that case I'll try to get the power issue sorted and then squeeze my spaghetti monster into whatever box I can find to see if it still works. If you get the more advanced version of this built and create a schematic for it please let me know, I'll have a go at making it.

and as for your panner, it could be done with a pair of vactrols, with anti-phase leds driven by an lfo. easy-peasy. ish. on the BB, at least.

Aaah there you go speaking pure g(r)eek to me I'm not sure if I should be aroused or confused...

[moid]

"and as for your panner, it could be done with a pair of vactrols, with anti-phase leds driven by an lfo. easy-peasy. ish. one the BB, at least."

Ouh ouh Mr Beesley.
Now that sounds like a project I could have a go at.......

Hi Kipper4 I would be really happy if you did, I know what a vactrol is, but how it should be mated with 'anti-phase leds' is beyond me. That sentence does read like something Scotty would say when warp factor 5 would be required in an emergency and an excuse would be trotted out about how "ye cannae get the parts these days cap'n" So if you do decide to make something like this I would be very grateful, thanks!

[moid]

I'm obviously way behind with this -  but what, may I ask, does the green LED do on the PT2399 pin 7?

It doesn't have to do anything, it just looks ravishing:) It complements the pt2399 perfectly dahling

In reality I have no idea what it does, but it does flicker impressively if I hit the circuit with a chord while the feedback and modulation setting are turned up. It warns you that what you are about to hear might not be recognisable as a delay signal!

[Hatredman]

What software  ?

Pen and paper. For simple circuits and quick drawings, it's the best one.


Sent from my iPoor using Tapatalk - now Free because I'm poor

[bluebunny]

Mr Beazley. What tv series was that from?

Was it the hair bear bunch?

Mr Peevly.

As you were...

[moid]

once gndA and gndD are connected to GND, it doesn't matter where your other gnd connections are/go, because they are all the same. you might try upping the value of that 1k resistor, cause there seems little use to the fastest end of the delay pot, to my ears (cloth, dirty).

Thanks duck_arse, you were right Changing the 1k resistor was the solution  I settled on a 2k2 in the end; it didn't have any appreciable effect on the sound as far as I could discern and didn't seem to do anything to the minimum delay time. I got my son who has the ears of youth on his side to check the circuit with both resistors and he couldn't hear any difference either. I am really happy, thanks ever so much for all your ideas and help, I'm looking forward to boxing this tomorrow! I'll try to record a demo of this with my son if I can get it boxed and still working!

In case it matters to anyone I've updated both the schematic and the vero layout in case anyone else fancies building this version of Knutolai's pedal.

[duck_arse]

nice work. your bass-cut cap shows 47pF on the circuit dia, but 470pF on the layout.

also, have you checked your "messages"?

[moid]

Thanks very much - it should be 470pF, whoops!  (at least that's what I used and it works). I've updated the schematic above. Finally boxed it all today and it still works, also the hiss seems less so that's nice too. If I was going to build it again I might drop the switch for the capacitors that affect the tone - they work, but the effect isn't that strong and after playing with it on a bigger amp and not on headphones it isn't worth adding that part of the circuit for the hassle, or maybe I should've swapped the last 220nF for a 470nF which did only give one long repeat and then a blast of sound... hmmm.... do pedals every actually get finished or are they something you tinker with forever? I really like adding in more wet repeats and being able to lower the bass rumble though.

Wow, I just looked in my messages, thanks ever so much! Yes there will be some questions, I am going to read through the schematics and use google to help me answer lots of questions and then try to limit the queries I have for you to the ones that no one else can help me (Obi Wan) Would it be more useful to start a new thread on this forum for the panner function in case it is useful to other people?

[knutolai]

Hi and sorry for the endless radiosilence!

Impressed with what you've managed to squeeze out of my very minimal circuit moid. I like the addition of the "More Wet" pot. Without it the wet volume is dependent on the feedback strength (IIR Comb Filter network) https://en.wikipedia.org/wiki/Comb_filter

Wont get around to read the whole thread (and I'm terrible at reading vero layouts!) so if there are any questions please repost them.

Here are some quick mods to try with the original circuit:
Delay Bass Reduction:
-Reduce C15 or C16 size.

Alternative SelfModulation implementation (will need adjustment):
-Remove Modulation Pot, R3 & C3
-Replace R7 with B500k pot
-Add 1k resistor between PT2399 pin14 and R2-DelayPot-junction.

Less High cut:
-Increase/decrease C13
-If delay level drops too low try (with bigger C13) increase C11

Finally. Since the workshop December last year I've made new, more complex versions of the circuit. If there is interest for it I could try have a post up of the latest v. (has dry/wet mix and a feedback footswitch) in a new thread (I'll post a link here).