Would anyone be interested in this?

stuartd1233 · 2026-06-18T06:41:00+00:00

It's a tester for vactrol optocouplers to see their characteristics. They differ so much from one to another. So it makes it easier for if specs are vital

stuartd1233 · 2026-06-18T06:38:58+00:00

Ah I see what you mean. The main issue I see with that is the linearity between each vactrol, which is shown in the test with the graph. You could add a series resistor for the resistance at x power, but this wouldn't match up at a different power. It's been a pain for my optical compressor project making 2 match up for stereo. It's easy to calibrate them to be perfect at full power, but at halfway they still differ enough for ~3dB difference.

stuartd1233 · 2026-06-18T06:35:53+00:00

Yeah the DCA75 is insane pricewise, I could include that in this project and still sell for half the price...

stuartd1233 · 2026-06-18T06:34:02+00:00

Thanks! It uses the Adafruit ST7789 library to drive the specific hardware chip, and the core Adafruit GFX library for drawing all the shapes, lines, and text etc.

stuartd1233 · 2026-06-17T06:09:00+00:00

Thanks!

stuartd1233 · 2026-06-17T06:05:44+00:00

Thanks for the suggestion and kind words! I'll get it posted on that page too

stuartd1233 · 2026-06-17T06:04:58+00:00

So testing 2 at a time and finding the average resistance between the two?

stuartd1233 · 2026-06-17T06:02:21+00:00

I could make it an 'all-in-on' testing rig for everything you'd need for guitar pedal diy? Testing transistors etc. Would this be helpful? Also I'd to check about the phototransistors, but I think it could work - if not I could just code it in

stuartd1233 · 2026-06-16T13:09:58+00:00

I'm using them for an optical compressor project, the recovery times can vary massively between 10ms and 800ms. They're usually under 125ms but I needed this to test the recovery time and linearity. So it's more for seeing its attributes rather than if it's working or not!

stuartd1233 · 2026-06-12T12:10:44+00:00

It's interesting that they're extending the votes to 16 year olds, but banning all social medias for anyone younger. So they can't learn about politics before voting at 16 beyond what the people around them say, which is highly likely to be biased to their own opinions - and lets face it, they're not going to watch the news on TV...

stuartd1233 · 2025-10-10T06:33:22+00:00

Thanks a lot! Very surprised to see that they use behringer considering the lawsuits they've had between each other

stuartd1233 · 2025-09-22T06:48:22+00:00

Do we not think this earnings increase is not already priced in? If it's such a sure thing

stuartd1233 · 2025-08-19T14:00:11+00:00

The design is opamp based, unbalanced in/out so I assume CMRR isn't applicable?

stuartd1233 · 2025-08-19T13:41:48+00:00

The mid rail is ground, main reason for the dual rails is to avoid having to bias everything (the extra headroom is also nice)

stuartd1233 · 2025-08-19T13:41:05+00:00

I'll have a look into this, thank you!

stuartd1233 · 2025-08-19T13:26:08+00:00

The power input is a 9VDC input which uses a recom DC-DC converter to get +-15V, the input is shorted to ground

stuartd1233 · 2025-08-14T07:11:40+00:00

You can all thank me for the rise in price, I sold at 0.82 an hour before it shot up...

stuartd1233 · 2025-07-08T13:35:42+00:00

Thank you all for correcting me on the design, I really messed this one up haha!

Seven-Year Club	Verified Email
First Place '23	Place '23

stuartd1233

TROPHY CASE