Confused about How to wire the input jacks

[captainhaha]

Hi Everyone,
First off thanks to everyone on this site for their generosity and time. This is my first post mainly because I can normally find the answers to my questions without having to ask!

I'm building a few things from E-M at the moment, namely a pair of MPS and a Klee. I'm at the stage of wiring the inputs for the MPS, I'm using phono jacks not banana's, and I just don't get how to wire the n.o & n.c jacks up

I've scooted around a few forums and found as many diagrams as i can on the MPS thread but i'm still confused about which switches and jacks I need. I should point out that as i'm fairly new to this(only built an E-D pixie before) i'm just doing a stock build on rev 107 boards.
Could someone enlighten me please or point me in the direction of a tutorial that explains it.

'Regards,
C.

[elmegil]

An "n.o." jack is normally open. An "n.c." jack is normally closed, also described as switched.

Normally closed jacks have an extra lug for each main lug (1 for mono, 2 for stereo). When nothing is plugged in, whatever is wired to the switch lug will be connected to the main lug, as if *that* were plugged in. As soon as you plug a jack in, this connection is broken. This is commonly used for things like making sure an unused CV input is grounded, or "normaling" which is connecting an internal signal through to another stage, with the option of overriding that normal connection with a jack inserted in the plug. The ARP 2600, for example made extensive use of normalled inputs so that you could use it without patch cords if you used the normal signal routing.

Normally open is a standard mono jack. Nothing special, and you can use a normally closed jack, just don't wire the switch lug.

On the MPC, the main use I recall for the switched jacks was for the effects send/return loop. This is entirely optional. The output has the switch lug wired to the switch lug of the input from the loop, so with no jacks inserted there's a constant signal flow, but if you want to process something (say the impact) with an external effect (say an echo) you could plug the out and in jacks through the effect, and the normal signal flow is interrupted and substituted with the effect processing.

[captainhaha]

hi elmegil,

Thanks for the quick reply, i'm going to have to digest this and post a drawing I think:)
Somewhere along the line I failed to realise the send/return was for audio/fx. I thought it was for CV of some sort.

Brb,
Cheers,
C.

[elmegil]

The horse's mouth: http://birthofasynth.com/Thomas_Henry/Pages/MPS.html