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Messages - bushidov

#1
General Questions / Re: TDA7266M and the 10 Min Amp
June 01, 2020, 10:01:17 AM
Hi JackSkellington,

Aw, you do appear to be correct on the issue of Out+ and Out-. The silk screen is reversed. Thankfully, due to the isolated jack and it being a mono amplifier, there isn't any issue of phase. That's what had me pondering, as I use a 10 minute amp for testing pedals and "it works", so I was a bit confused when I saw this. I have corrected the silk screen for the batches after this, but in this case, flip-flopping the speaker out wires won't matter. As Aentons mentioned, 6 and 7 are tied together on the backside of the board.
#2
Does this help? These are the pins I assigned.
#3
Open Discussion / Re: The zombie chorus - it's a trap!
December 08, 2019, 02:28:50 AM
Quote1. Is there some reason to use 1uF electrolytic and not a non polarized? I'd use a non polarized.
Just space and cost, at least in this case. There isn't much on this circuit that you are doing that would require that 1uF to be able to switch faster than what an electrolytic can handle.

Quote2. Is there some reason to use TL062 and not TL072?
TL062 uses less current than the TL072, but at the cost of being slightly more "noisy". If you made a version that never was going to use a battery and always would be using a wall power supply, then TL072 all the way. If you were using 9V batteries only, TL062 might squeeze a little more lifespan out of that battery.
#4
Open Discussion / Re: The zombie chorus - it's a trap!
December 02, 2019, 11:29:59 PM
Hi there. I am Erik, who works with Chromesphere (dbe/diygp) and these are the main things I applied to this pedal to make the noise go away.
1. I used a ground plane. The CD4046 is a noisy chip (ask folks who designed 8-Bit computers and used them) and it needs "thorough" grounding.
2. I made sure the op-amp for the input and output buffer, as well as the op-amp for the square and triangle wave creator were as far away as possible to that CD4046 because, again, that chip is noisy.
3. The noise tends to be loudest at the resistors that come off pins 11 and 12 (aka R1 and R2) of the CD4046. I kept those resistors on the furthest side of the board (which in turn will be close to the walls of the enclosure, a make-shift faraday cage). They are also kept close to the CD4046 and then grounded close via the ground plane mentioned in list item 1.
4. I made sure the bias had a trim pot. Like the designers of the Boss CE-2 before me, it is well understood that BBD chips are more sensitive to BIAS drifting than other chips and discrete components, so careful fine tuning will help with the performance dramatically.

I am not saying that's a "slam dunk" to fixing the issues, but they were concerns I used to make sure the board I designed didn't have the ticking issues, and it seems to have removed all of them.
#5
Sound anything like 2 minutes into this video?
https://youtu.be/skMPD5_4XHE