A B box

From giorfid–(at)–ellatlantic.net Fri Feb 7 10:17:06 CST 1997
From: “Fly on! free bird!”
Newsgroups: alt.guitar.amps
Subject: Re: Do It Yourself (DIY) Projects
Date: Tue, 04 Feb 1997 23:10:08 -0500
Reply-To: giorfid–(at)–ellatlantic.net
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit

A B switch with led’s…

(2) 1/4″ mono phone jacks
(1) 1/4″ stereo phone jack
(1) DPDT footswitch (available from stewart macdonald, as well as
(2) led’s (preferrably of different colors)
(1) 220 ohm resistors (lower values = brighter leds, higher
values=dimmer leds and longer battery and led life),
(2) led sockets,
(1) case,
(1) 9v battery and clip/socket

how to:
(1)drill the case for the 3 1/4 jacks, footswitch, and led’s…
(2) snap in the led’s and sockets, install footswitch, the mono jacks in
the holes for a and b, and the stereo jack in the common jack,

(3) wire as follows:


| 1 2 3 |
| |
| 4 5 6 |

a. connect pole 1 of switch to tip of a jack, pole3 to tip of b jack,
and pole 3 to tip of common jack
b. tie all grounds common, as well as cathodes of leds.
c. tie + of battery to resistor, and other end of resistor to pole 5
d tie pole 4 to anode of led a, pole 6 to anode of led b
e. tie cathodes of both led’s to ground
f. tie – pole of battery to ring position of common jack
g. double check your connections, plug in and go

From j_atchle–(at)–maginet.net Fri Feb 7 10:17:29 CST 1997
From: j_atchle–(at)–maginet.net (John A.)
Newsgroups: alt.guitar.amps
Subject: Re: Do It Yourself (DIY) Projects
Date: Fri, 07 Feb 97 14:53:52 GMT

I say, was that Ton who wrote?
>220 ohm in series with LED at 9Volts?
>Is this 220 not a bit too low?
>This would mean: I = (9-2(LED voltage drop)/220) = 31.8mA !

Not a big deal, except to battery consumption — the author even mentions that
higher resistors can be used for longer battery life, dimmer LED.

I’ve built (and used for years) 50ma current-regulated NiCad trickle chargers
with an ordinary red LED (T1-3/4) in series in the charging circuit. Some of
these chargers have run almost continuously for 3 years, and I’ve never had an
LED fail.

Most LEDs will reach their “peak” of brightness around 20ma though — they’ll
get a _little_ brighter as the current goes above that, but not by a lot. I’d
probably go with a 330 ohm resistor as the difference in brightness isn’t
going to be as significant as the longer battery life. But, the 220 ohm
resistor isn’t going to _hurt_ anything and 31.8ma isn’t worth an exclamation
mark :>) unless you’re using one of the very low-current LEDs.

Would 31.8ma decrease the life of the LED? Maybe, theoretically. But, when
taken against the normally almost infinite life of an LED, I’d have to say it
is more likely the rest of the pedal will fall apart first…:>)


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