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31
Building your own stompbox / Re: AB bypass looper pop
« Last post by idy on Yesterday at 08:35:03 PM »
Have you tested to see if any of your pedals is leaking DC on the input or output? Really the question would be if the string of pedals in the "clean" side is doing it.

You may not need all that, the caps and such. I would be suspicious of the stomp switches, the cheapies don't always perform noiselessly. It's a simple pedal, I would try to build another (if this works, you'll want two anyway) and maybe spring for a "better" stomp switch.
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Building your own stompbox / AB bypass looper pop
« Last post by kr2p on Yesterday at 08:12:23 PM »
Iím having a little trouble with an AB bypass looper popping when I switch between the two loops - a clean one which has a load of pedals, and a dirty one with just a Rat thatís always on. The pop is most noticeable when I have a delay on in the clean circuit as you get all of the repetitions which is quite annoying.

Itís a completely passive AB looper and Iíve tried a bunch of things. Originally it was just a plain true bypass switcher which linked the unused send to ground and left the unused output floating. This popped. I tried the most basic thing of putting 1M pull down resistors on all sends and returns. Still popped. I then added .1uF capacitors at each send and return along with the pull down resistors, the idea being to treat the effects in the loop as one big active circuitry requiring its own input and output caps. This still popped. I also tried 1k current limiting resistors before the capacitors at the sends and after the capacitors at the returns. This still popped. For clarity the latest setup looked like the final figure in this link

https://www.mrblackpedals.com/blogs/straight-jive/6629778-what-really-causes-switch-pop

with the ďcircuit blockĒ in the diagram essentially being all of the pedals in the loop.

The pedal has an LED but the ground is separate to the audio ground, so as far as the audio path is concerned thereís no LED or power going to the pedal so this isnít the problem. And to verify this it also pops when I donít plug in the power.

Iíve tried going straight in with my guitar into the input, as well as going through a buffer and it makes no difference. Iíve tried moving it next to and away from a power supply to see if it is some sort of induced noise but thereís absolutely no difference so this isnít it either.

I feel like Iíve run out of ideas here so if anyone has thoughts that would be amazing. I should mention that I have a boss LS2 which doesnít pop as itís an active buffered circuit, but Iím trying to avoid using it as it adds a bit of hiss which seems unnecessary since a passive pedal should be able to do the same thing.
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Huh.  I thought alkaline was alkaline.
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Building your own stompbox / Re: Germanium Tchula boost debugging
« Last post by willienillie on Yesterday at 07:28:37 PM »
willie nillie, was this what gave it away?
Quote
6.65v on both when footswitch is engaged.


cheers

Well, same voltage on collector and output wire.
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Recently built the same vero layout w/LF353s and the LED/LDR may take some tweaking to get right. I'd definitely suggest butting the LED right up to the face of the LDR & sealing it with a few layers of black heatshrink tubing. The increased proximity will increase the amount of "squish" you get from it, as well as helping isolate it from stray light. That isolation is super important as any stray light will end up causing gain reduction even when you're not playing.

If you really want to improve the squash, you can:
  • Change R19 - Lower resistor value = more LED drive current & more signal shunted to ground (more gain reduction). Higher resistor value = less LED drive current & less signal shunted to ground (less gain reduction)
  • Change R5 - This is R1 in the gain-reduction voltage divider, the LDR is R2, so the amount of gain reduction is equal to R2/(R1+R2). You probably want your R6 to be in a similar range what your LDR is when you're playing. Somewhere between 1/2 & 2x the value of the LDR worked for me for R5
  • Increase R6 - With the Comp knob up, if you are getting more volume drop than you can make up with the Level knob, increase R6 to 6.8k or 10k to increase the amount of makeup gain. I had to use a 10k in mine.

I found that with my knock-off eBay vactrols, the on resistance was SUPER low (less than 1K), so I had to both increase R19 & decrease R5 in order to use the right part of the LDR resistance vs LED current graph. With homemade LED/LDRs, the rise/fall time of the LDR is also a factor, but testing that is quite a pain.
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Building your own stompbox / Re: The (new) Gristleizer - mods?
« Last post by The Crooked Man on Yesterday at 06:17:12 PM »
Quote
I'm not seeing a point A anywhere in one these images. 

See,
- original article, page 560, Figure 1
- right-hand side, wiper of Depth pot VR4.  Wire is marked "A"

Wow. I have absolutely horrific eyes, but even so, I have no idea how I missed that.  Thank you!
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Building your own stompbox / Re: The (new) Gristleizer - mods?
« Last post by antonis on Yesterday at 06:11:29 PM »
More clear now..??  :icon_wink:

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Building your own stompbox / Re: GGG ITS8 help
« Last post by antonis on Yesterday at 05:44:40 PM »
More than perfect..!!
(congratulations on your DMM impedance, also..)
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Building your own stompbox / Re: ESR Graphic Fuzz Power Supply
« Last post by antonis on Yesterday at 05:41:39 PM »
The circuit has that 220ohm and 100nF cap on the output as well.  No doubt that effects the tone.  Even more surprising perhaps is with the network present the pot load has an audible effect.

BTW, it brings to mind a Zobel network (Bucherot cell) designed for some speaker of 180R/5mH, or so..  ::)
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Building your own stompbox / Re: The (new) Gristleizer - mods?
« Last post by Rob Strand on Yesterday at 05:35:35 PM »
Quote
I'm not seeing a point A anywhere in one these images. 

See,
- original article, page 560, Figure 1
- right-hand side, wiper of Depth pot VR4.  Wire is marked "A"
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