[newbees] when your switches pop ...

[gaussmarkov]

i just spent many hours at my bench (so many, i'm not going to tell you the total) debugging a popping switch in a dual mosfet booster.  i read many forum comments about this (thanks esp. R.G. and Mark Hammer).   i put in pulldown resistors -- still popped.  i grounded the circuit input in bypass -- still popped.  i laughed.   i cried.    i wondered whether the problem was something special about the dual mosfet circuit or whether the switch was bad.   but the grey beards (term of respect for the wise) had spoken, and i stuck (reluctantly  ) with the possibility that it was neither of these.

in the end, it was poor solder joints.  probably several.  simple as that.   these can cause subtle mechanical problems that cause pops.

my lessons: 

• if you have switch popping problems and you have pulldown resistors and/or a grounded input in bypass, open up your enclosure and push the wires around inside while the circuit is connected.  this revealed the problems that i was having:  loud pops caused by very slight movements of the hook up wires.   i had poor connections on the switch and a bad one to the board.  and just because you move one wire and get a pop doesn't mean that's the one with the poor connection.  it could be another wire that is barely moving at the same time.
• don't doubt the clear, simple advice of our grey beards

cheers, gm

[skiraly017]

Is the jury still out on whether or not the current draw caused by a LED can cause popping? I've been playing around with an LPB-1 build lately. With a LED, I get switch pop. Without a LED, none. I've done the pulldown resistor thing and check all my joints and connections. The only way I lose the pop is by losing the LED. I'm using super violet LED's from Small Bear with a 2.2k limiting resistor for that "Oh my god it's so bright it's giving me a headache" look. Any thoughts on this?

[gaussmarkov]

Is the jury still out on whether or not the current draw caused by a LED can cause popping? I've been playing around with an LPB-1 build lately. With a LED, I get switch pop. Without a LED, none. I've done the pulldown resistor thing and check all my joints and connections. The only way I lose the pop is by losing the LED. I'm using super violet LED's from Small Bear with a 2.2k limiting resistor for that "Oh my god it's so bright it's giving me a headache" look. Any thoughts on this?

last i saw, the LED can be a problem.  i think Mark Hammer suggested using super bright LEDs as a help, because they draw less.  i was not using an LED.

edit:  you probably saw this:  http://www.diystompboxes.com/smfforum/index.php?topic=45332.msg331724#msg331724
actually, i was thinking of an earlier, similar remark Mark made.  i had not read this thread and my comments are not directed at anyone's experience reported there.  i am saying, however, that at one point i was convinced that my taiwan blue 3pdt was bad.  even switched it out for another.  but R.G. said,

There is some popping inherent in every hard mechanical switch. This is due to the suddeness of the switch contact. If the switch contacts happen to touch when the signal is at a non-zero level, then there is a sudden infinitely-steep transition from the dry to wet signal, or viceversa. That sudden change can sometimes be perceived as a click.

However - it's really, really rare for it to be objectionable.

What you're describing is indicative of some other problem.

... and he was right. 

[stumper1]

Have you tried a larger resistor for the current limiter?  I know it won't look as cool - but I am still curious.  After reading Z-Vex's suggestion of using higher values current limiters (10k or higher) it would be cool if you could try it and see if it makes any differnce.

[skiraly017]

Have you tried a larger resistor for the current limiter?  I know it won't look as cool - but I am still curious.  After reading Z-Vex's suggestion of using higher values current limiters (10k or higher) it would be cool if you could try it and see if it makes any differnce.

I thought about that. 10k sounds awful high though.

[gaussmarkov]

for those who have not seen it (i missed it), zachary vex's suggestion re super-bright LEDs and a current limiting resistor:
http://www.diystompboxes.com/smfforum/index.php?topic=44109.msg320749#msg320749

[stumper1]

I thought about that. 10k sounds awful high though.

I agree....but if it works.......  I haven't had popping issues but have raised mine to 10k for MOST LEDs.  I usually use the water clear 3mm ones that SB sells.  I used to use 4k7 - they are still plenty bright with the 10k.  As for how 10k will look with yours ?