Skeptical buffer introduces noise when harmonics switch engaged

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MikeTinsley

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Just a quick one - my Skeptical Buffer sounds fantastic apart from introducing noticeable noise when the Harmonics switch is engaged - the Brights switch also introduces a very slight (almost inaudible) amount of noise when engaged. Has anyone encountered this before (and hopefully solved it!)? Any and all help gratefully received!

Thanks,

Mike
 
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Any solutions to this one, I have the same occurrence going on. When the pedal is engaged with all switches off, its silent, if I add harmonics or bright switch there is white noise sound coming through (harmonics far worse than bright) and none with the low switch.
I cant seem to tune it out with a noise gate in the chain afterwards.
Interestingly some other pedals after in the chain can tune it out - I think my lowtide was one of them? Not sure if its a buffer issue there.

I've switched 1044 charge pumps out with the one in my Kliche, didnt seem to change anything. Tried it daisy chained and not daisy chained on my Iso-Brick (no change with either power)
I see another poster with a similar issue here too
https://forum.pedalpcb.com/threads/skeptical-buffer-high-pitch-sound.21570/ @itstimtime
 

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zeropluszero said:
Any solutions to this one, I have the same occurrence going on. When the pedal is engaged with all switches off, its silent, if I add harmonics or bright switch there is white noise sound coming through (harmonics far worse than bright) and none with the low switch.
I cant seem to tune it out with a noise gate in the chain afterwards.
Interestingly some other pedals after in the chain can tune it out - I think my lowtide was one of them? Not sure if its a buffer issue there.

I've switched 1044 charge pumps out with the one in my Kliche, didnt seem to change anything. Tried it daisy chained and not daisy chained on my Iso-Brick (no change with either power)
I see another poster with a similar issue here too
https://forum.pedalpcb.com/threads/skeptical-buffer-high-pitch-sound.21570/ @itstimtime
Click to expand...
Never got it figured out. I know in that previous post people suggested swapping out IC’s, but nothing changed for me.
 
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No idea what to make of this
Was just playing my guitar with the skeptical on, HB switches on, L off. If I use the transistor tape emulation in my HX stomp, I can get 6+ repeats of the delayed note with my feedback at about 70%. If I use a different algorithm Adriatic, the same amount of feedback percentage, gives me about 2 repeats with the skeptical on, and 6+ with it off.
How would this buffer, before the delay, cause there to be a cut off of repeats based on different digital algorithms?
 
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zeropluszero said:
No idea what to make of this
Was just playing my guitar with the skeptical on, HB switches on, L off. If I use the transistor tape emulation in my HX stomp, I can get 6+ repeats of the delayed note with my feedback at about 70%. If I use a different algorithm Adriatic, the same amount of feedback percentage, gives me about 2 repeats with the skeptical on, and 6+ with it off.
How would this buffer, before the delay, cause there to be a cut off of repeats based on different digital algorithms?
Click to expand...
that is weird
 
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I just put one of these together and it doesn't make noise. It looks like we have the same IC's. The only thing I can think of is perhaps the 3pf disc cap? Here's mine

2Hqx4Di.jpeg
 
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The "harmonics" switch is just a high frequency boost so its more likely to bring out any fizzy white noise in your chain.

Maybe try putting a cap from pin4 to ground and pin8 to ground of the opamp? If for some reason you have a lot of psu noise that should help a little.
 
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zeropluszero said:
well I put the long one through the positive holes, and then clipped them off so I hope so.
Click to expand...
So I was just checking the PCB, and the tantys do have little indicators for the anode, and they definitely are in correctly. I tried switching out the opamp with some other 72s and even an opa2134, no difference, and switched the charge pump with another as well. I've tried my Isobrick, a wall wart and even a battery, no difference.
I'm not sure if I should push out the tantys and plug in some cheap caps, see if that fixes the noise, or at this point just pull all the parts and throw it out.
Kind of a bummer because I like the switched on sounds, but the noise is too much
 
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have you tried it with a basic setup? guitar-pedal-amp - and then the power to the pedal not connected to anything else?
does changing your guitar pickup selection and volume/tone change the noise?
It's possible the high input impedance is making something audible that's being filtered out otherwise (ie the buffer isn't the issue in and of itself.
Try a parallel 1M resistor across R1 to lower the input resistance to 0.7M
 
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