Need an osc 1k tone for test box. [SOLVED]

[blearyeyes]

Need a simple 1k tone for my PCB test box. Would like to install it inside of this:

[BricksnBeatles]

Signal generator phone app and a 1/8" to 1/4" adapter?

[blearyeyes]

i actually have that already but I want the OSC to be ready without the hassle of hooking up my phone for workflow reasons. ADHD and I'll be using my phone for somethin else after wandering around the house looking for it... haha.. but thanks for the idea.

[jwin615]

If you just want sound and not worried about a clean sine wave, more of a binary circuit works or doesn't, and you don't want adjustable frequency, you do make a reverse avalanche oscillator.
3 parts, npn, cap and a resistor
Plenty of info around but here's one link
https://www.electronics-notes.com/articles/analogue_circuits/transistor/simple-one-transistor-relaxation-oscillator.php

A few more components and you can make a wein bridge oscillator. It's basically a rc network tuning an opamp that is feeding back into oscillation. Wein bridge makes a very clean sine, is tunable, but can be touchy in regards to consistency of oscillation. There are variations that use a lamp bulb or fets for gain compensation.

There are also the various 555 circuits. Some yield a sine, others square. Here a link to an astable variation that will produce a sine.
https://www.learningaboutelectronics.com/Articles/Sine-wave-generator-circuit-with-a-555-timer.php
If you go the 555 route and order parts, grab a CMOS variation (lmc555 or the other model, I forget) in addition to the traditional ne555. Sometimes the ne555 can make switching noise on the ground that the lmc doesn't. It's early and I don't remember why
I think it's current related as the lmc uses way less current being a CMOS device

[blearyeyes]

Thank you!

[blearyeyes]

Found this. Got it from Aliexpress for $5 US delivered. Video on YouTube shows how to make it better. Apparently uses fake XR2206 chip that becomes unstable over 12v whereas a certified one works fine. The video covers how to clean up the existing circuit if needed for more critical or high freq uses.

https://youtu.be/02XtneCHnDA?si=_cc98JAfxK7JzGCA

[blearyeyes]

Recommended mods:

[jwin615]

Recommended mods:

I have one of those I've futzed around with. For the R2 pot, I'd go with the smaller value as these output way hotter signal than a guitar.
I never finished mine but had mounted trimpots on vero to a switch to basically switch between preset levels for guitar and bass.
You'll get more than enough volume at 9v so 12v shouldn't really be a concern.

[blearyeyes]

Yeah, I’m going to run it @9v did you try those mods?

[blearyeyes]

Finally...

[jwin615]

Finally...

I love it when a plan comes together.
No, I think mines in the pcb graveyard box currently. I can't remember if I fried it, borked it or just got tired of fooling with it.
I recently bought a dedicated bench laptop and a 2 ch interface. Plan to use a software generator and analyzer (SMAART). Just need to cobble together a reamp box of some sorts.

[blearyeyes]

I blew up I my first Capacitor! I am so brainwashed by building guitar pedals, I automatically made it negative tip power. Hmm... why isn't this working? Splat!

I've graduated.

Everything else survived for some unknown reason..... Replaced the cap and whoop dee doo. I have two Chinese toys to play with. I would prefer real tools but I need the brain to go along with them.