Build Your Own Clone Message Board

Hi friends,

Currently working on my Green Pony build; the clipping switch isn't working properly at the moment. Left position seems to work fine, middle position completely cuts audio signal, and right position sounds much lower in volume. About to reflow the board, but overall, feel pretty confident on quality of my soldering. I did add some 2X sided tape underneath the B250K pot, as initially it seemed like it was shorting the signal and also found an extra piece of solder on one of the lugs that I cleaned up.

Any insight?

https://www.dropbox.com/scl/fi/g6h1hkzso1d16hikgu1pw/IMG_3662.jpg?rlkey=zd1ekydsyfkd9h7q0zq0adps1&dl=0

https://www.dropbox.com/scl/fi/q6tn5gvgh9jdst8c5ic3w/IMG_3663.jpg?rlkey=cny2jy8sl6mc1osty2wee6lft&dl=0

Does the Gain control work with the switch in either of the two outer positions?

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Yes it does work in the two outer positions. All controls seem to function normally in both outer positions.

Do you have access to a multimeter and know how to measure continuity with one?

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Yes I do, where should I check contiuity?

We need to look at the connectivity of that clipping toggle switch. Please do this: Disconnect your power source and set your multimeter to the continuity mode. Set the Drive pot to its midpoint and the clipping toggle to the middle position. Referring to the PCB map below, measure for continuity between the left-most lug of VR1b and the center lug of SW1. Set the clipping toggle to the LED side and repeat this measurement. Then set it to the Si side and repeat again.

Return the clipping toggle to the middle position. Now set your meter to the resistance mode and measure the resistance between the middle lug of SW1 and ground. For the latter, I would suggest using the SLEEVE tab of the input jack.

Report all your results here.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Hi, thanks for the instructions; very helpful.

Continuity:

Good in all positions b/t VR1B left lug and all three lugs of SW1.

Resistance:

It seems to vary a bit. Starts at 4M Ohms and keeps climbing. Been pretty consistent at 6.64M Ohms, 7.14M Ohms.

Are you aware that the clipping switch's effect is determinate on the position of the gain knob? It becomes less effective as you turn down the gain. I'm not sure where on the dial, but it eventually becomes completely nullified.

So when testing the clipping switch, you need to have the gain knob turned all the way up.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

Yes, that makes sense for sure. Let me retest the clipping switch with the gain dimed.

One other question; I noticed the first time I fired up the pedal, the clipping LEDs lit up (as they should I would imagine), but they no longer light up at all. On any settings of the gain or level knob. So, I replaced them and still get the same issues; middle position on the switch there is no output and in any position the clipping LEDs do not light up.

Is there something shorting the clipping LEDs then?

The LED's are probably working fine....just not in the way you're expecting. In this mode of usage, their function is not to light up but rather to divert (i.e. clip) some portion of the audio signal away from the output path and thereby introduce some signal distortion. The first part of THIS ARTICLE describes it better than I ever could. The amount of the signal that gets clipped will be that portion that exceeds the forward voltage threshold (FVT) of whatever type of clipper you're using. Because these LEDs have a high FVT (something in the range of 1.5 - 2V), it takes a very strong signal (by electric guitar pickup output standards) for them to clip a portion it. Since the signal is the strongest at the initial attack of the note, that's where the most LED clipping will occur. But in most pedal circuits with LED clippers, that only happens for a short time interval, maybe a tenth of a second or so. But if the signal is strong enough, it will light up the LED as it's clipped, though usually dimly & briefly. Here's your best bet for being able to see it: Dial your Drive control up to the max, plug in a guitar with a strong output (most humbucker guitars will suffice nicely), set the clipping toggle on your GP to the LED setting, and turn off the lights in a room with little or no ambient light. Now strike a chord HARD and see if those LEDs flash on for a moment. I'll bet they do.

Incidentally, this clipping behavior relates to another observation you made. Since different kinds of diodes can have widely different FVT's, they will clip more (low FVT) or less (high FVT) of the signal. This explain why you heard a substantial volume difference between the LED and Si positions of the clipping toggle switch. Silicon diodes typically have an FVT in the 0.5 - 0.6V range, so they clip a much larger portion of the signal than the LED's. More signal clipped = less signal output. It also means a more distorted and compressed output.

What baffles me about your problem is that you are getting NO output with the clipping toggle in the middle/off position (i.e. no signal being passed through either set of clippers), which should give the strongest output. I can't even understand how that's possible. But maybe Keith/byoc has an idea for that one....

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

That's what I thought on the LED's, but it never hurts to give as much info as possible.

Alright, so last bit of clues I can think to add to this mystery:

When you strike a note or a chord, rather than the decay "naturally" fading away, you get this "spitty" sound like a gated fuzz circuit that feels like it chokes the note at the end of the decay. It happens in both left and right modes of the clipping switch.

When you switch from left to middle position on the clipping switch, the overall loudness increases very fast and then poof, no signal, so that makes sense about your statement that the middle should be the strongest signal.

So is it a bad or the wrong transistor, potentially? Or just a bad switch? Am I crazy? Probably...

Anyway, thanks for all of the insight thus far.

Sounds like it could be a funky solder joint somewhere. You mentioned doing a total reflow--did you complete that? Here's our recommended procedure: viewtopic.php?f=9&t=52188

BTW, does the position of the Norm-Thin-Fat toggle affect the behavior?

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Yes, I did the total reflow, same issues. The Norm/Thin/Fat toggle worked fine in the left and right clipping positions.

After the total reflow, I desoldered the 250K pot and the switch to inspect them. I'm pretty sure I might have fried the switch at some point and it was positioned pretty tight against the pcb, so my guess is that's the issue. I guess I'll order a new switch and maybe a 250K for shits & gigs and see if that fixes this mess.

Who new building a pedal could be so maddening!!!

Thanks for the help and insight once again.

I'm going to go out on a limb and say that most of us here knew that, having learnt it the hard way

I had some super weird behaviour with a pedal once that was caused by a tiny solder bridge between two lugs of a footswitch, between the footswitch and the PCB on which it was mounted, so it was completely invisible -- at least that's a problem that you won't encounter with BYOC kits

Solving the problems is often when we learn the most.

Do not attempt to replace either the switch or pot at this point.

It's physically impossible for your problem to be the switch. The middle position connects to nothing. It would essentially be as if there were no switch at all. The worst possible fault would be that the switch puts the LED and Si diodes in parallel, which would simply cause clipping to default to Si.

Your problem is something else. I would assume the the increase signal output of no clipping is overloading one of the op amps further down the line. Please take voltage readings of the two op amps and let's see what's actually going on.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

Here's how to do that:

To measure the DC voltage level on the IC pins, set your multimeter to the DC voltage mode, indicated by a solid line above a dotted one. Use the 20VDC range setting if it's not an auto-ranging meter. Your power source needs to be connected and there needs to be a cable in the input jack. If the pedal is assembled into the metal enclosure, put the black probe into one of the corner screw bosses of the enclosure--this is your ground connection. If the "guts" are out of the enclosure, use the sleeve tab of the input jack for the ground connection. Then touch the red probe to each point that you want to measure. See image below for the numbering of the pins.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2