pulldown resistor on input jack ok?

[dennism]

I've got a pedal that I built from a vintage schematic that didn't include a pulldown resistor.   And it's popping like crazy upon being switched on.   There isn't any room on my veroboard to add a pulldown resistor, so I'm wondering if it's OK to just add it on the input jack from the input lug to the ground lug?   Seems like it would be fine and do the same thing, but just wanted to make sure I'm not overlooking any potential problems that this could create?

[deadastronaut]

try it with croc clip leads...

should be on you board though..

i would just tack a 1M on the solder side of the vero...

[induction]

If it's on the input jack, it will be unconnected to the circuit in bypass, so it won't do anything useful.

[Cozybuilder]

From the circuit input lug on the switch to ground will do it. Use 1M on up.

[GibsonGM]

From the circuit input lug on the switch to ground will do it. Use 1M on up.

Won't harm anything, if you use a high value as suggested...

[dennism]

Thanks to all who replied.   Glad I asked first.   I actually took a fresh look at my veroboard and found a way to incorporate a 3.3M resistor from input to ground with a bit of a stretch.   It's not pretty or best practice, but it works.

[mth5044]

I second the input lug to ground lug on the switch. Almost as easy to incorporate as the input jack, but infinitely more useful.

[armdnrdy]

I actually took a fresh look at my veroboard and found a way to incorporate a 3.3M resistor from input to ground with a bit of a stretch.   It's not pretty or best practice, but it works.

Look at how MXR "stretched" out resistors in the older Phase 90s.



Have no shame! Sometimes we just need to implement a fix after the fact when there is no "pretty" way to do it.

[MrStab]

Look at how MXR "stretched" out resistors in the older Phase 90s.

i've been meaning to ask this lately: from time to time, whilst looking at boards from CD players etc., i'll see ceramic caps or resistors soldered to the bottom. On single-sided boards. Are they fixes for errors on the board? or for performance issues, at least? i just find it hard to believe, as it's always big-name brands i've found this on.

[FiveseveN]

Yeah, and it doesn't matter how big the brand is. Sometimes you notice (potential) issues late down the line and decide re-spinning the board isn't worth it. If your production already involves manual soldering, adding a bypass cap, pulldown resistor etc. isn't a significant expense.

[CodeMonk]

Yeah, BBE did it on their early Ben Wahs.
They cut the input trace and stuck a 1k resistor in there for RF on the trace side of the board.
(Info straight from Paul Gagon)

[MrStab]

interesting stuff. i guess it's easy to see some of these companies as infallible robots, but given the sheer number of connections involved, it's probably less likely for there to be NO mistakes.

i have a stash of boards from 2 separate iTead orders which i deemed unsellable because i had to use jumpers to make up for forgotten traces! goddamnit!!!

maybe there should be an all-round "biggest blunders in commercial pedals" thread. that'd be fun.

[Mark Hammer]

Commercial pedals that use electronic switching often have no pulldown resistor on the input, simply because they can get away with it.  Trouble is that when you stick a true-bypass pedal in front of it, that non-pulled-down input cap gets connected and disconnected by the preceding TB stompswitch, and you get a pop out of it.  Tends to drive folks crazy, because the e-switched pedal makes no pop on its own, and the "pop ventriloquism" of the TB pedal is not the sort of thing that folks can easily deduce.

Pop-immunizing an e-switched pedal CAN be achieved by stradding the hot and ground on the input jack with a suitable-value (1M-3M3) resistor.  However, the same approach doesn't work on a TB pedal.  There you need to actually connect the pulldown resistor to the circuit board input itself. though I suppose connecting the corresponding switch lug to greound through a pulldown will work.