madbeanpedals::forum

Projects => General Questions => Topic started by: cloudprofessor on September 21, 2017, 06:44:42 AM

Title: Tried to build a KoT, ended up with a dual oscillator
Post by: cloudprofessor on September 21, 2017, 06:44:42 AM
So for the past three months I've been meticulously building a King of Tone with an 18v charge pump inside from the tagboard layouts. I'm doing a build with separate i/o for each side, but they're tied to the same

Tonight I put the first board in and was met with a loud drone where the you can somewhat control the pitch with the drive knob. Flipping one of the clipping switches gives it a different pitch range. I figured it was something with the wiring or maybe with that specific board so I put the next one in thinking it would work but I got the exact same issue.

Anyways, I feel like I've double and triple checked everything and I have no idea what the issue could be. My charge pump is giving 18v out, the board seems fine no solder bridges, and as far as I can tell my wiring is good.

Anyone here might know what specifically might be causing this, or at least where to start looking? I'm going to check the IC with a multi-meter tomorrow, and maybe ok around with the oscilloscope as well.

Side note, it actually sounds kinda cool. I put it through my LS-2 as a mixer/sum pedal and was playing around with the individual oscillations, harmonizing them together.

I can post pics tomorrow.
Title: Re: Tried to build a KoT, ended up with a dual oscillator
Post by: Luke51411 on September 21, 2017, 11:34:06 AM
Could be a charge pump issue. Which one did you use?
Title: Re: Tried to build a KoT, ended up with a dual oscillator
Post by: cloudprofessor on September 21, 2017, 05:05:13 PM
This NE555 one from tagboard: http://tagboardeffects.blogspot.ca/2013/02/ne555-voltage-doubler.html

Just because I happened to have a bunch of ne555s on hand. I've built a few of the same ones for a ROG Supreaux Deux build I did previously and had them work just fine. Also I checked with the multimeter and it's giving me about 18.23 volts. Both boards are tied to the one charge pump though, even though they have different ins and outs.
Title: Re: Tried to build a KoT, ended up with a dual oscillator
Post by: cloudprofessor on September 22, 2017, 04:05:17 AM
So I tried taking the charge pump out, still getting the drone sound. I tried playing around by removing some of the grounds and it did some weird stuff but didn't fix anything overall.

If anyone wants to hear what it sounds like: https://www.instagram.com/p/BZUHTPuFIsv/?taken-by=geoff_lg
Title: Re: Tried to build a KoT, ended up with a dual oscillator
Post by: alanp on September 22, 2017, 04:18:20 AM
Which PCB are you using for KoT? There are quite a few PCBs out for it, by now.
Title: Re: Tried to build a KoT, ended up with a dual oscillator
Post by: cloudprofessor on September 22, 2017, 02:09:11 PM
Tagboard layouts: http://tagboardeffects.blogspot.ca/2012/10/analogman-king-of-tone.html

I think I figured it out though. Upon going through the board piece by piece I found I didn't put one of the 100uf caps in the right place. I fixed it and I get crunchy guitar noise through it, though the knobs are still acting weird so I've still got some work to do.