Recent content by bowanderror

Wow those hand-taped PCBs are GORGEOUS! Looks in decent enough shape, although the presence of flux & heat marks on only some pads makes me wonder if there are undiscovered mods & component changes (other than what you've had to do). Same goes for the bodge wires, are those part of the MIDI...

I think the Q2/Q5 dual JFET is just a high-impedance input stage for the opamp (which itself is just a buffer). In terms of testing in-circuit, you're best bet is probably testing it in-use, monitoring voltages with a scope as you trigger keys on the keyboard. Maybe someone else can chime in on...

Yeah, worked out great! I'm actually about to do the same piezo mod to my main guitar. I don't think the mounting location I chose for the first guitar was ideal (center of pickup cavity), so I plan to test a bunch more spots before installing. I 3D printed some piezo mounts to try as well...

Man, this thing keeps getting cooler with every post. The talk of variable sample rates & aliasing options has me thinking about emulation modes for other digital gear, like the E-mu SP-1200 sampler. If I recall correctly it's 12-bit 26kHz, and the clipping & aliasing from the ADC/DAC is a key...

The image link was dead, but I wanted to see the graph. So for future me/anybody else, here's a version I found on another forum: And another plot vs. other common tapers:

The 2159 is just a bottom of the barrel spec'd 215x-series VCA. You should be able to replace it with a 2155, 2150, or 2151. The specs, and therefore costs, increase as you go from 2155 to 2150 to 2151. These will still be hard to find, as they have been mostly replaced by the 2181 & 2180...

I used the recommendations in these comments to change the resistors. I can't recall offhand what values I went with, but I'll check next time I have it open.

Thanks for the build report, I've got one ready to be boxed and your mounting notes will be useful! I followed some recommendations on how to improve the Dwell knob from this thread. I'll have to check my notes and see exactly what I did, but it definitely delivers a more intense reverb sound...

Getting folks to take a systems approach always seems to be a struggle, for some reason it's harder to get capital for infrastructure upgrades than it is for "shiny new toys". I bet that 100W laser would cut through 1/4" acrylic like butter! Damn, that's a cool combo of materials & processes...

That looks nice! I've used the metallic Gravoply a few times, but it often had some odd & uneven texture on the unengraved areas. Maybe this thinner material is a bit more uniform, I'll have to give it a shot. What wattage are you working with on those Universal machines? We have two...

Yep, usually 1/16", occasionally as thick as 3/32" or thinner down to ~0.02"

At work we use Gravotech Gravoply and it's the most consistent in terms of quality and lasability (is that a word?). I can't remember which particular material type we use, probably Gravoply Ultra. If we can't get Gravoply, we'll use Rowmark, but it's a little more unpredictable in terms of...

I was wondering the same thing today. Somebody found some cases of leaded solder from before my work went ROHS and asked me if I wanted them. Now I've got 50lbs of Kester 44 just as I was running low...

I'm finishing mine up and have the same 386N vs 386L question. Did you end up testing both?

Is this circuit sensitive to JFET specs? I usually socket SMD JFETs on an adapter PCB, but I'm tempted to just solder them directly if it's not picky. I've tested & used a bunch of this SMD J201 batch, so I'm not worried about them being super out-of-specs or fakes.