The RMA drawing board/etc.

[$harkToootth]

What's happening fellow frogs!?

[Dandolin]

Still permeable

[crochambeau]

I'm still working the Stone Splitter circuit. I've observed drop-outs when the octave divider is following a signal down low (frequencies that are probably of no concern to a guitar player, but important ones nonetheless), so it's a bit of massage the circuit action over here. I'm confident I'll have the section (a very established circuit in early analog computing circles) sorted soon.

[crochambeau]

I was having issues with the bistable flip-flop section falling into a monostable region at about 30 Hz input frequency and ignoring any subsequent triggering until the input frequency climbed to over 100 Hz. Completely unacceptable. Furthermore, in order to establish the bistable (only changes state when a trigger is received, and stays there until next trigger) I had lopsided values of resistance.

It turns out this was due to poor loading conditions at the following stage, which was just jumper shunted in for test/listening. So planting a higher impedance buffer before the mix/recovery sections should resolve this. Feeding only the higher impedance input stage of my bench amplifier resulted in stable flip-floppery down into fractional Hz.

I've also drafted a daughterboard assembly to interface with the 40 pin connector and provide three functions via three switches: three position waveshape for each octave section, and a series/parallel switch for main mode. I've got some contingency settings built into the schematic, so it's a little more cluttered than it could be, but for good reason (in my opinion).

[$harkToootth]

OMG... this is one of your first posts where none of the information went completely over my head! My stupid amphibian brain (cause we're frogs) is learning!
This is all very exciting! Especially the three functions via three switches! Thanks for posting!

[$harkToootth]

I follow RMA on Instagram now. I would love to see RMA become a social media “influencer”.

[crochambeau]

I follow RMA on Instagram now. I would love to see RMA become a social media “influencer”.

My apologies. I sustain a terrible presence on instagram, I think I pop in once every 2-3 weeks. In order to be an influencer I think I'd need to be rubbing my elbows together every day.

I'm aware of the deficiency, hahahahahaha.

[BetterOffShred]

What's happening with the stone splitter?

[$harkToootth]

What's happening with the stone splitter?

My hommie B.o.S. asked... not me! But I am equally anticipating!

[crochambeau]

The stone splitter is a grimy fuck, and I'm just working out how much patina versus spit polish I will employ.

It is very, very close.

I have this stupid thing where I want something to perform some fucked up function "well", while also performing normal functions in a fucked up manner. Hifi fighting lofi for a seat at the table, but choreographed to the whim and intent of whomever operates the beast.

It is close.

[BetterOffShred]

Hot diggity daffodils! Well I'll buy one when they are ready my man. Done deal!

[$harkToootth]

For those curious (at least 10 people), how are you working it? I saw you have the pcbs... do you work off one and tune or are there uh... derivatives that sound very filthy?

[crochambeau]

For those curious (at least 10 people), how are you working it? I saw you have the pcbs... do you work off one and tune or are there uh... derivatives that sound very filthy?

This is a somewhat convoluted subject, I'll try to legibly encapsulate it though.

This circuit departed from the prototype on the schematic level in a few areas. So, some schematic level changes occurred and subsequently the entire PCB was redrawn (this happens to be my standard approach, as I enjoy the puzzle solving of laying out traces and paths).

The stages that were essentially "cut and paste" were initially populated with the values I had settled on in the earlier prototype. Adding in other sections can introduce conditions that affect things or were otherwise unforeseen, so back tracking and course correction work often needs to be done*.

(*please note, that a lot of my terminology and thinking is based on signal path)

My designs tend to lean toward filth/grain/murk/mayhem/instability/whatever because of the sheer volume of active sections at play. The Stone Splitter base PCB (main circuit) has 21 transistors, with two additional transistors on the plug in switching module required to complete things. I'm sure "good" engineers who adhere to a lean philosophy will scoff at those numbers, but I am satisfied that the end result departs enough from anything birthed in a lean design environment to merit my preference of path.

Anyway, I spend more time on chasing the core functions than I do dirt, by which I mean I aim to carve the widest path between root function and absolute mayhem as I can. But this is audio, and that whole element of working all night on a mix only to have it sound like shit in the morning applies.

So my process begins with one build out. If that gets too hairy (several layers of rework) sometimes I'll populate a fresh board with the "current" value set. Once I get that board in a place that I find a joy to use (where the audio goblins live and shit) I'll build out another board as a first generation "consistency" test. Sometimes that's a bummer and I need to move back a few squares.

Ultimately, my goal is to have a recipe of values that I can stuff that will provide consistent results, but sometimes locking in a fixed value set takes several builds or extended burn-in cycles so variations early on are not surprising.

[$harkToootth]

"good" engineers...

[$harkToootth]

Me thinking about the Stone Splitter...

https://www.youtube.com/watch?v=6FEDrU85FLE