[sdiy] Stompbox power (was Re: Socket schematic symbol question)

[Tom Wiltshire]

On 2 Nov 2010, at 16:39, Neil Johnson wrote:
> Tom Wiltshire wrote:
>> Neil Johnson wrote:
>>> Why not use a p-channel MOSFET to switch the power, with its gate
>>> pulled low by the mono-in-stereo ground ring switch?
>>> 
>>> Cost increment is pretty small (one transistor, one resistor) and it
>>> minimises the current through the jack plug.
>> 
>> Ok, but what's the advantage? I don't get it (but it's been a long grey day...).
> 
> You don't put the battery across the input jack as it is pushed in?  I
> dunno, I guess it depends on personal preference, and how cheap and
> crackly you want to be.

It's only the battery -ve terminal, so it's not like you're feeding 9V back up the jack lead.

Do I want to be cheap and crackly? Dunno. It's funny how these things go around though. When I was younger, the Boss pedals were highly regarded because they featured 'noiseless switching' (done with a couple of FETs and discrete flip-flop attached to the footswitch). Nowadays everyone wants 'true bypass' and people are modding the old Boss pedals to remove the noiseless switching!

T.