Anderton build question

[tonepoet]

Hi all,
    I was looking over Craig Anderton's book 'DIY Projects for Guitarist' and I was interested in combining 2 effects. Being a pretty new and not so great DIY'er, I need some help. Project 14 is a signal switcher, in which there are 3 different outs and one in, or vice versa. There are also 3 LED's for each out. Then project 23 is a true bypass switching box. What I would like is to have a true bypass box (in which to loop my effects on the pedalboard) and be able to have another switch that will mute it all and send it to a separate jack for the tuner (which is kind of an A/B in a sense). In essence, it's the signal switcher with only 2 outs (one to tuner and the other to the next switch) with the bypass added. I would like each 'loop' to have it's own LED (that's 3 in all). The thing that boggles me the most, besides the order of things, is powering the LED's from 1 nine volt battery. Is this possible? Has anyone ever built something like this? any help would be greatly appreciated.

[Mark Hammer]

Almost anything is possible from a 9v battery, except making it last forever under heavy current-drain conditions.  Having a bypass/loop box is not one of those.  Bear in mind that such a box may *have* 2 LED's but that doesn't mean you use them both at once.  Even if it did, there are plenty of superbright LEDs out there that require much less current for the same degree of visibility.

All you really need for what you are trying to build is a 1590BB box, a 3PDT switch, 6 jacks (one stereo, one mono, and 4 mono closed circuit), two LEDs and 2 suitable current-limiting resistors.  That should come in well under $30 in the worst case conditions (although seeing your location maybe I should hike that a bit for shipping).

The switch is wired up so that the master input and output jacks connect to the common/centre lug for two sets of contacts.  The input common is then routed to send-jack-1 or send-jack-2.  The common tied to the output jack goes to receive-jack-1 or receive-jack-2.  Each pair of send-receive jacks is wired up so that if nothing is plugged in, the send and receive are hard-wired together.  That way the box doubles as either an overall straight-wire bypass plus loop or a choice-of-loop box.

The 9v battery goes to the common of the 3rd set of contacts, and power is routed via a suitable resistor to each of the two indicator LEDs, then ground.  The stereo input jack is, of course,used to turn on the battery.

That's it.

[Yazoo]

:shock:

I am going to build the EPFM noise gate, and have a couple of queries I wanted to check if anyone would be kind enough to help. I think these are probably doh! questions, so sorry in advance.

I think the noise gate uses the bipolar power supply. In a bipolar supply using 2 9v batteries, is it right that only 9v is actually going through the circuit, not 18v, the voltage you would get with 2 9v batteries in series?

The second question is about the ground connections from the input and output jacks. These don't get connected directly to the circuit board. Am I right in thinking that the connection is actually via the ground lug which is connected to a ground point on the board itself?

[Rodgre]

:shock:

I am going to build the EPFM noise gate, and have a couple of queries I wanted to check if anyone would be kind enough to help. I think these are probably doh! questions, so sorry in advance.

I think the noise gate uses the bipolar power supply. In a bipolar supply using 2 9v batteries, is it right that only 9v is actually going through the circuit, not 18v, the voltage you would get with 2 9v batteries in series?

The second question is about the ground connections from the input and output jacks. These don't get connected directly to the circuit board. Am I right in thinking that the connection is actually via the ground lug which is connected to a ground point on the board itself?

A bipolar supply establishes a point (which is ground) which is half the supply voltage. In the case of the Anderton projects, if you're using a 9v bipolar supply, you've got +9v - ground - and - 9v. If you measure from positive to negative, you've got 18v. Positive to ground you've got +9v, and negative to ground, you've got -9v.

As for the ground connections, keeping the board connecting to one ground lug on the chassis is a good way to avoid ground loops.

Roger