RMA Dirty Doper

[Jwar]

GOD HURRY UP!!!

[Chankgeez]

LOL.

So, jwar, got any suggestions for improvement on the Dirty Doper?

[Jwar]

Not really. It was pretty perfect when I had one. I'd like to think I'd have a good suggestion, but I need the circuit in front of me as my memory sucks. hahaha

[crochambeau]

LOL.

So, jwar, got any suggestions for improvement on the Dirty Doper?

Seriously, I'm all ears.

1) Right now the big structural change is going to be PCB mounted switches (I haven't decided on pots yet), I've railed against PCB mount panel controls for years.. so this hurts a little, but I'm just going to shut up and do it. Future repairs will gauge if this was a good idea or not, but it'll save a lot of time now which is expensive.

2) I'm planning on reconfiguring the front end a bit to allow deeper excursions into non-distorted territory, at least allow it to clean up a little bit more.

3) I'd like to design the low pass section so that it is switchable to either side of the signal path (so three position switch: LP on lower branch, LP bypassed, LP on upper branch) the problem is cost & availability of required mechanical switch. So implementing this feature would entail CMOS switching, which opens the door for additional features & CV trickery.

4) The differential stage that sits over the instability control (and is where a fair amount of the voicing comes from) will probably need to be a monolithic matched BJT pair, as short of hand matching and thermally coupling the two transistors consistency was all over the place in this section. I'll probably draw the pads to take SOIC & through hole so I can mismatch that in the event my prior analysis is full of shit.

5) If I go with CMOS switching I might get playful and build in some CV controlled feedback paths to push it deeper into the oscillating fuzz realm.

[lordgalvar]

All sounds awesome! The CMOS switching/CV stuff could be a blast.

Why not do the switches on a second control board (maybe include pots)? I know it would add to cost, but it could save you some headaches in repairs while still making things easier to wire.

It's weird seeing CMOS. I was expecting some kind of discrete xor/xnor/and network for switching/activating BJT switches.

I think footswitch-able branching/crossover would be a fun option at some point for a quick second voicing. (I always kinda wanted that two footswitches one so I could have two haha).

I think the CMOS thing could work out really well honestly. Excited man. (I have this giant multiplexer network of feedback loops and paths in my head controlled by cryptic toggles haha....I know it won't be like that, just kinda a quick image in my head of like a space age EMS pin matrix)

[crochambeau]

I have this giant multiplexer network of feedback loops and paths in my head controlled by cryptic toggles haha....

Hahaha, yeah - I want to avoid adding more switches if possible. I don't think I can get rid of any. My thought is to add another CV port that feeds four comparators that will open/close the feedback switching, maybe leave triggering point of each to the user through some set & forget trim pots and allow them to latch the oscillator switches on without adding CV (which remains a black art for many). Another thought is to plumb in a DB9 and offer a break-out box or pinout data to the DIY crowd, but we're veering into jumping on a higher expense tier with that sort of thinking.

I don't want to fuck with going discrete on the logic side, I'll take 4000 series hahahaha. Otherwise the footprint will be too cumbersome.

I like the daughterboard switch/pot idea, though I'd still have to engineer main PCB mounting. I'm really leaning on going whole hog on it, maybe widen the trace to pad so butterfinger repair people have to work harder to lift traces.

[amnesiac305]

Looking forward to this....I never got to try the original

[resincum]

I have an idea: can you possibly reduce the output? moving the vol knob one small tick can mean absolute aural annihilation not always a bad thing tho

[crochambeau]

I can work on the taper of the volume knob for sure.

[Jwar]

The volume on all your pedals are brutal though.

I think it's why I'm fond of them so much.

Though my ears agree with Resincum.

Also, is this done yet??

[crochambeau]

HAHAHA, thanks!

No, it's not done yet...

The wide open volume would be unchanged, it's just the ramp up from nothing...

...which brings me to master volume all the way off - current revision thinking would *not* have that as full off like seen in the Dirty Doper, but as a diminished volume. Am I wrong, is full off useful?

[resincum]

full off is always useful for me. more room on the ramp is perfect tho

[crochambeau]

I realize there's a hanging trace on this, it has been corrected.

[goroth]

YEEEAAAH!

[Chankgeez]