Wiring a rotary switch - Impedance selector

[cat]

Hey guys,

So I got my Ceriatone 5F1 kit and Ive had the parts all out for a few days just checking that everything was there and mentally putting it together before I plug in the soldering iron.

Anyway, I realised that I have no idea how to wire up the rotary switch for the impedance selector. I mean I know how to identify the wires on the OT no problems but the problem is with the fact that I have 4 wires to connect (4, 8 & 16ohm taps and Ground) and there's about a thousand lugs on the back of the switch (pic below).

Can anyone provide any help with this. Thanks guys, this forum has been an invaluable source of info so far.





Cat

[Robert M. Martinelli]

You' ll need a DMM set to measure continuity, the internal lugs are most probably "commons" while the outer lugs should be the different "ways". Rotate the rotary switch fully CCW, tie one of the DMM probes to one "common" with the help of alligator clips, then, with the other DMM probe, find ( and take note ) of the "way" ( lug ) currently connected to that common - move the rotary switch one position forward and repeat the procedure, and so forth - you only need one "common" and three "ways" - one for each tap - the common will go to the speakers' female jack, if any, or directly to the speakers - technically this kind of switching is described as a "single pole-triple throw" to highlight you are routing a single wire in three different directions.
The other speaker' s lug will go to the other end of the OT ( usually at GND potential ).

Hope this helps
Best regards
Bob

[Enzo]

My first thought is contact the kit seller. First, they are familiar with the parts they sent. Second, feedback as to potential sources of confusion helps them improve their product for future buyers.

To me it LOOKS like a 4 pole 3 throw switch. The four inner legs are the four common legs. Each one of them is associated with three of the outer ones - four groups of three with an inner each.

IF THAT IS THE CASE, then connect a wire from the speaker out jack tip to - pick one - one of the inner ones. Then the three taps go to the three outer legs associated with that particular inner one.

Check this out, it is a very crude drawing of what I mean.

http://www.ampix.org/albums/userpics...P3T_wiring.PDF

[Chuck H]

Picture the switch like figure 1. That should clear things up. The final wiring will probably look alot like figure 2. Your - OT secondary will be on the mains - jack lug. Your feedback loop will be on the switch lug with the appropriate OT secondary.

You can wire the switch like this or as Enzo proposed. The lugs on those switches are really close together for an impedance switch so I usually do it this way.

Chuck

[tubeswell]

and when you have finished wiring the switch up, before you connect it into the circuit, check the continuity with your R-meter at different settings and make sure there is only continuity between each of the 4R-Gd, 8R-Gd, 16R-Gd, and no continuity between any of the 4R, 8R and 16R poles and you'll be fine (assuming you'll want to wire it up so that it delivers one of any option to a single output socket)

[martin manning]

A really up-town way to wire these is to parallel 2 or 3 or even all of the SP3T switches so that you have extra current-carrying capacity and transformer-saving redundancy if one of the contacts should ever go bad.

MPM