DIY begginer, speaker switcher!

[MikeFFG]

Originally Posted by milosjanic

Hi everyone, my first post here.
I recently got interested in diy electronics, as I have a ton of electronics components, hardware and tools that I got from my father.
As I said in the title, i want to start with something simple like a passive speaker switcher. I saw some schematics and it doesn't look hard to make, and the good thing is I actually need one.
I want it to have one set of inputs (L+R) from audio interface (Emu 0404) in my computer, and preferably 2 x L+R outputs for my speakers (Esi Unik 05 and Microlab B73), with on/off switches for each. I saw everyone recommend stepped attenuator for volume control but it's too hard to make one (for me), and can't find one to buy. I could put potentiometers, but many people say they could screw up the balance. So i could go without volume controls, as i can control volume directly on speakers.
So, I would need a schematic for this. I found one in a similiar thread made by user (thimoteee) but I guess it would need some modification to suit my needs. As you can see on his schematic there is an inpit impedance of 90 ohms, but on my emu 0404 it's 22 ohms, so i guess there should be something different (probably with resistors?). He also used 4PDT switch but i could use a normal switch for each output. If anyone could make suggestion or a schematic for me I would highly appreciate your help.

Hi - first off, not to send you away from this forum, but definitely check out groupdiy.com for all things diy audio. There are definitely some monitor switches on there.

Next, your impedance should be fine. The schematic seems to be saying that it expects a 90 ohm output impedance from the interface, but the input impedance of this switcher is much higher (note the 2k ohm resistors at the inputs of both L and R), which is good. You pretty much always want a low output impedance into a high input impedance, so the 22 ohms from your interface is even better than the hypothetical 90 ohm interface this person is using. I think you also probably want to use two Double pole double throw (dpdt) switches for the speaker on offs, one for each set of speakers. It looks like this one switches both sets at the same time or something weird like that?

Anyways, I'm still not an expert but that's my two cents. I would go digging through groupdiy and find something...do some searching! Good luck!