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DIY Stompboxes => Building your own stompbox => Topic started by: fif_freakboy on July 24, 2010, 02:56:47 PM

Title: Pop goes my pedals with new buffer.
Post by: fif_freakboy on July 24, 2010, 02:56:47 PM
I just threw together a ic buffer from GGG on a perf board and plugged it in and it worked right away. Then the problem arose, whenever I now switch on any other pedal on my board it makes a popping sound. I have all pedal running off of a one spot. Help!

Also, I built it without an led and without a switch. I have it wired to always be on.
Title: Re: Pop goes my pedals with new buffer.
Post by: Morocotopo on July 24, 2010, 04:11:03 PM
Sounds like you removed the pulldown resistors or the coupling caps, that could cause the popping. A schem would help to see where´s the problem.
Title: Re: Pop goes my pedals with new buffer.
Post by: fif_freakboy on July 24, 2010, 04:25:02 PM
I'm using the schematic from General guitar gadgets  for their ic buffer. I built it to the specs of the schem, no idea what I did wrong.
Title: Re: Pop goes my pedals with new buffer.
Post by: fif_freakboy on July 24, 2010, 04:49:36 PM
I went over the schem and compared to my build, looks correct to me. This is my first time building from scratch with a perfboard. Usually I just use pre-made pcbs so this my first trip out doing this.
Title: Re: Pop goes my pedals with new buffer.
Post by: Ronsonic on July 26, 2010, 12:45:48 AM

If the wiring is sound and correct the first suspect would be the output cap. Measure to see if there is a DC voltage on the output of your buffer. There should be some sort of resistor to ground as a pull down. Even with a good cap a voltage can develop across the output, especially if your TB pedals don't have pulldowns. Anything will do, 100K is what I would grab, just tack it across the output jack to git 'r done.
Title: Re: Pop goes my pedals with new buffer.
Post by: Jay on July 26, 2010, 04:43:00 AM
The GGG buffer doesn't have any output pulldown, so that could be a problem.  I'd go a bit higher than 100K - 1M if you have it.

You say any pedal on your board pop's.  If the first pedal after the buffer is on and then you switch another on and off does that pop?  If so it's not a pulldown problem and is power related.  Try running the buffer off a battery and see if that clears it - could point to a grounding issue with the buffer perhaps.
Title: Re: Pop goes my pedals with new buffer.
Post by: fif_freakboy on July 26, 2010, 01:26:35 PM
I tried the pulldown and did nothing. I then tried the battery and it made no difference. I take it then that I have a grounding problem. Where do you think I should start?
Title: Re: Pop goes my pedals with new buffer.
Post by: Jay on July 26, 2010, 03:51:40 PM
Well, I'm surprised the battery trick didn't fix it.  Maybe check your leads, guitar to buffer and buffer to first pedal.  Swap them one at a time for a different lead, see if that fixes it.  Check the ground connections within the buffer on the jacks and board - reflow the joints.

If that doesn't work I'm running low on ideas....
Title: Re: Pop goes my pedals with new buffer.
Post by: fif_freakboy on July 26, 2010, 06:46:00 PM
Thanks for the help guys. I decided I'm just going to start over and redo it. As it was my first time out without using a pcb it wasn't a very clean job. Probably has some bad joints or something. I might just get a pcb from AMZ or something like that. Any recommendations?
Title: Re: Pop goes my pedals with new buffer.
Post by: .Mike on July 26, 2010, 07:29:23 PM
Quote from: Ronsonic on July 26, 2010, 12:45:48 AMIf the wiring is sound and correct the first suspect would be the output cap. Measure to see if there is a DC voltage on the output of your buffer.

Have you done this? Was there any DC on the output?
Title: Re: Pop goes my pedals with new buffer.
Post by: Ronsonic on July 29, 2010, 01:09:56 AM
Quote from: .Mike on July 26, 2010, 07:29:23 PM
Quote from: Ronsonic on July 26, 2010, 12:45:48 AMIf the wiring is sound and correct the first suspect would be the output cap. Measure to see if there is a DC voltage on the output of your buffer.

Have you done this? Was there any DC on the output?

This

If there is measurable DC on the output (or the input for that matter) it will cause this problem. You need to check this.