Weird interaction between two pedals.

A

ADAOCE

Well-known member
As the title suggests, I have a delegate boneyard edition that works just fine but when I run my dark rift down the chain I hear what sounds like the charge pump noise. It only appears to be audible while the dark rift is on. Both pedals work great otherwise. So not a typical troubleshooting thread just curious why this might be occurring.
 
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Also interesting to note is that if I run my quaverato in front of the dark rift I can very faintly hear switch noise from the blinking rate led. It’s gone if I put the trem after the dark rift. That switch noise in the quaverato is not really noticeable with the dark rift bypassed. It seems to me like my dark rift is allowing that sound to be heard when other pedals are not
 
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I'm not too surprised this is happening. Charge pumps make noise around 40KHz that can get aliased down into the audible band when the noisy signal is sampled. Flangers use BBD (bucket brigade devices) that sample the signal at variable frequencies near 40KHz or its harmonics. PT2399 delays also sample the signal at variable frequencies that can be near 40KHz or its harmonics. I don't have a good answer on how to fix this other than to avoid charge pumps. If you have 18V power available, then you can remove the charge pump in the Delegate, run it on 18V and the problem should go away. If the charge pump is socketed, just pull it out. Make sure C100 is rated for 25V or higher.
 
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Chuck D. Bones said:
I'm not too surprised this is happening. Charge pumps make noise around 40KHz that can get aliased down into the audible band when the noisy signal is sampled. Flangers use BBD (bucket brigade devices) that sample the signal at variable frequencies near 40KHz or its harmonics. PT2399 delays also sample the signal at variable frequencies that can be near 40KHz or its harmonics. I don't have a good answer on how to fix this other than to avoid charge pumps. If you have 18V power available, then you can remove the charge pump in the Delegate, run it on 18V and the problem should go away. If the charge pump is socketed, just pull it out. Make sure C100 is rated for 25V or higher.
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Thanks Chuck. I do have 18v available so maybe I’ll give that a shot and see what it does. Is there any charge pump you prefer over another in terms of noise? I think I have a mix of TC1044, LT1054 and 7660s in various pedals on my board. The BYOC silver pony I have uses a 7660 and is totally silent in terms of charge pump noise.

I also dare to guess that other circuit factors might come into play not just what charge pump is used. Anyways thanks for replying
 
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The Silver Pony, like the original Klon, uses much smaller capacitors (1uF) in the charge pump circuit compared to the 10uF caps used in most charge pumps circuits. That may be a factor. How much power the charge pump needs to pump is probably also a factor. I have a C3 (Chinese Clon Clone) and a VFE Merman. The Merman has 22uF charge pump capacitors, so it will be interesting to compare the two. I know that my Vibronaut, Crunch Captain Deluxe and modified Chela all make 40KHz noise that gets aliased in the 'lectric Mama & at least one other flanger of mine.
 
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Chuck D. Bones said:
The Silver Pony, like the original Klon, uses much smaller capacitors (1uF) in the charge pump circuit compared to the 10uF caps used in most charge pumps circuits. That may be a factor. How much power the charge pump needs to pump is probably also a factor. I have a C3 (Chinese Clon Clone) and a VFE Merman. The Merman has 22uF charge pump capacitors, so it will be interesting to compare the two. I know that my Vibronaut, Crunch Captain Deluxe and modified Chela all make 40KHz noise that gets aliases in the 'lectric Mama & at least one other flanger of mine.
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Good info thank you
 
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