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DIY Stompboxes => Building your own stompbox => Topic started by: ghiekorg on November 24, 2020, 10:23:04 AM

Title: Volume drop and weeping sound from Punk Repeater
Post by: ghiekorg on November 24, 2020, 10:23:04 AM
HI guys :)
Here is the layout: https://effectslayouts.blogspot.com/2014/11/dirty-punk-repeater-delay.html
Schematic SHOULD be this one, i haven't found a better one:
(https://i.postimg.cc/NL1mVj5j/dirty-punk-repeater.png) (https://postimg.cc/NL1mVj5j)

It works, the repetitions are kinda clean but i have 2 problems:
1- a really big volume drop when engaged. I used everything as layered out, i just changed the Q2 (BC459b) for a 2N5089 and i used 2 resistors (1M+330k) instead of the 250k i didn't have.
2- a sweeping sound when rotating the time knob: https://www.youtube.com/watch?v=UI5qxT5BFUo&ab_channel=ghiekorg (volume up :) )

Can you help me fix this?
Thank you
Title: Re: Volume drop and weeping sound from Punk Repeater
Post by: 11-90-an on November 24, 2020, 10:35:22 AM
My guess would be a flipped transistor

Weep sound is normal...  :icon_mrgreen:

If that doesn't work then pictures plez... :icon_mrgreen:
Title: Re: Volume drop and weeping sound from Punk Repeater
Post by: ghiekorg on November 24, 2020, 11:28:25 AM
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My guess would be a flipped transistor
Nope :D

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Weep sound is normal...  :icon_mrgreen:
So much? 0.0 i mean, there is a constant whistle

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If that doesn't work then pictures plez... :icon_mrgreen:
of the board? i would have to disassemble the pedal as i kept the wires super short  (i can take pics of the solder side though)

I was thinking maybe there was wrong (or something to be add) in the schematic (like something to push the volume up, addind a vol pot and some filtering session to filter the whistle) :/
Title: Re: Volume drop and weeping sound from Punk Repeater
Post by: antonis on November 24, 2020, 02:46:07 PM
Shouldn't an electro cap (10-47μF) be connected between pin 2 (Analog reference voltage - Vcc/2) and GND (Analog - pin3)..??

Title: Re: Volume drop and weeping sound from Punk Repeater
Post by: 11-90-an on November 24, 2020, 09:55:42 PM
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Nope :D

Just to get it straight, the perf layout showed the wrong orientation of the BC549. It is actually the correct pinout for a 2N5089 though... :icon_rolleyes:

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So much? 0.0 i mean, there is a constant whistle

Oops... didn't really hear it too well... :icon_redface:
Here's how the pedal should sound like... https://www.youtube.com/watch?v=a-aDx46PMaU (skip to 4:08)

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of the board? i would have to disassemble the pedal as i kept the wires super short  (i can take pics of the solder side though)
yea the board... but I think other forumites could come up with a solution without looking at component side pictures so maybe solder side will do for now... :icon_mrgreen:
Title: Re: Volume drop and weeping sound from Punk Repeater
Post by: Rob Strand on November 24, 2020, 10:45:29 PM
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Shouldn't an electro cap (10-47μF) be connected between pin 2 (Analog reference voltage - Vcc/2) and GND (Analog - pin3)..??
No cap across the 5V rails isn't good either.
Title: Re: Volume drop and weeping sound from Punk Repeater
Post by: anotherjim on November 25, 2020, 05:04:52 AM
The sweep whine would be expected with that design. It does almost nothing to prevent it. This might be deliberate, but I don't know why you'd want it to do that. Maybe I'm just not punk enough!
If you have a 9v battery snap to 2.1mm DC adapter, try powering it with a battery that way and see what happens to the noise.