DIY amplifier/speaker switching box

[sKiZo]

Nice!

Long as you're aware that some amps prefer to see a load at all times, so make before break might be more appropriate for hot switching? Maybe diodes to prevent feedback on the other amp?

The convenience is nice, but be sure you know exactly what you're dealing with on loads. Twere me, I'd make sure I always did the switching with both amps off.

 

[Hyperion]

Long as you're aware that some amps prefer to see a load at all times

Whatever they are (Valve amps?) I am sure they can handle it for a fraction of a second, and having 'make before break' is asking for trouble no matter what the amp output topology is IMO.

 

[whoaru99]

If using with tubes/valves, one could wire 100-150 ohm resistors in parallel with the amp outputs to ensure some sort of load at all times.

 

[whoaru99]

are my eyes playing tricks?
I see speaker inputs connected to amp inputs.
Shouldn't the amp outputs be switched to the speaker inputs.
Forgive me and correct me if I am wrong. Just making an observation.

No offense taken. I'm sure the drawing does look quite odd for someone who is use to seeing OP amp symbols used in a technically-correct way.

I did change the drawing to something perhaps more appropriate. Do you think it's better now with the different symbols to represent amplifiers?

 

[Bassblaster]

im thinking of making something similar to this. instead of 2 4PDT switches use 4 4PST switches. that way i can run 4 receivers to 1 pair of speakers...not all at once tho... maybe 4 4PST's going into a single 4PDT for 4 amps and 2 sets of speakers...i need to do some drawing on that

 

[ferninando]

yes whoareu, I am one of those someones.

 

[Amcrebelfan]

Cannot locate any at 32a and the one at 20a at parts express shows out of stock for me. Any other recommendations? I will run what's in my signature on my main system with this box. Thanks for sharing this DIY.

 

[Hyperion]

This is a 20A 4PDT with a centre off position - closest I can find at the moment.

http://www.mouser.co.uk/ProductDetail/NKK-Switches/S42/?qs=sGAEpiMZZMvudeGI7i40XPABurvEjtKZ8rQc7gDdfwo=

Or this one
http://www.parts-express.com/4pdt-heavy-duty-toggle-switch--060-572

 

[whoaru99]

Cannot locate any at 32a and the one at 20a at parts express shows out of stock for me. Any other recommendations? I will run what's in my signature on my main system with this box. Thanks for sharing this DIY.

Just about any one will work. It's unlikely you need such a big switch. 32A is like 8000 watts at 8 ohms.

 

[njcanuck]

FYI: Beware of the cheap and plentiful 4PDT Chinese switches commonly available on eBay. Every one that I bought had the internal bar break after just a few cycles. This can cause a short that will seriously upset your amplifiers!

 

[Amcrebelfan]

This is a 20A 4PDT with a centre off position - closest I can find at the moment.

http://www.mouser.co.uk/ProductDetail/NKK-Switches/S42/?qs=sGAEpiMZZMvudeGI7i40XPABurvEjtKZ8rQc7gDdfwo=

Or this one
http://www.parts-express.com/4pdt-heavy-duty-toggle-switch--060-572

Thanks for the links.

Just about any one will work. It's unlikely you need such a big switch. 32A is like 8000 watts at 8 ohms.

Great to know. I think I will order the parts express ones.

FYI: Beware of the cheap and plentiful 4PDT Chinese switches commonly available on eBay. Every one that I bought had the internal bar break after just a few cycles. This can cause a short that will seriously upset your amplifiers!

I was curious about the ones on ebay I will steer clear.

 

[JayPare]

Reviving this thread again!

There is 3 links where the switch is still available. Which one would you guys recommend?

https://www.mouser.ca/ProductDetail...=sGAEpiMZZMvudeGI7i40XPABurvEjtKZ8rQc7gDdfwo=
https://www.parts-express.com/4pdt-heavy-duty-toggle-switch--060-572
https://www.parts-express.com/4pdt-heavy-duty-toggle-switch-center-off--060-574

Or maybe something even better?

 

[biggal76]

Reviving this thread again!

There is 3 links where the switch is still available. Which one would you guys recommend?

https://www.mouser.ca/ProductDetail...=sGAEpiMZZMvudeGI7i40XPABurvEjtKZ8rQc7gDdfwo=
https://www.parts-express.com/4pdt-heavy-duty-toggle-switch--060-572
https://www.parts-express.com/4pdt-heavy-duty-toggle-switch-center-off--060-574

Or maybe something even better?

I have the cheap parts express one. I bought two because they were cheap. Not good quality. Had to flip it back and forth as it didn't make good connection. Installed the second one and it is somewhat better but still have to fuss with it sometimes. The Mouser one is probably much better but $30 shipped is pretty steep for a switch. I'd probably get the Mouser though.

 

[stoN_Cold]

Which one would you guys recommend?

https://www.parts-express.com/4pdt-...=1010X497171X4cc530b08642e2f8cfd640cb0f745c0a

 

[JayPare]

@stoN_Cold and @biggal76 isn't it recommendable to have one that has the power off in the center? I saw this one on Mouser:

https://www.mouser.com/ProductDetail/633-S43

 

[stoN_Cold]

Yes, but only 2A/250V AC.

 

[JayPare]

Yes, but only 2A/250V AC.

From what I see in the datasheet it's more like 9A isn't it?

 

[stoN_Cold]

Mea Culpa

S43

 

[ConradH]

FWIW, I just worked on one of the big Sansui switch boxes that you'd find at a dealer "back in the day". They use surprisingly complicated switching. When you start pushing any button, it opens a separate relay to disconnect/mute. I think it may also connect to some power resistors so the amp always sees a load. Though the speaker switching is fully floating, it appears all the negative speaker leads are common. Everything in it, in terms of switching, is custom. If I were trying to duplicate the function today, I think I'd go with relays and a PIC or something to insure the correct break before make behavior and loading while disconnected. I'm not sure about the loading as there weren't enough large power resistors for all the amps. There were some smaller ones that may have been just enough to insure stability on tube amps, maybe 50 or 100 ohms or so. Naturally there was no manual or schematic available. Regular switches make sense for a few amps, but not for ten or so!

 

[JayPare]

Mea Culpa

S43

Isn't it the exact same screenshot I posted above? I can't see the 2A/250V AC on it?

Edit: miss the mea culpa part!