Commstock
New member
Like many of you, I have more than one multi-channel amp and speaker set in my listening area. I would like to switch between amps and speakers, and there are beautiful audio matrix switchers that do this, but they are out of my price range. So this is an old school Quad amplifier/speaker switch. In this case it’s wired to switch between 3 quad sources and 3 quad speaker outputs. There is no load on unused amplifier inputs, so no “live switching” (switching between powered-up amps) is advisable; turn off all amps before switching.
I would have preferred to use better connection plugs, but I have limited space in my rack, so using these cheaper push connections allowed me to make a unit less than 2 rack units (3.5”) high. If you have the room, use the bigger banana plugs – plus it’s easier to drill a round hole than nibble out rectangular openings for the connections I used which, although intended for PC board mounting, were easy to wrap the wire around and solder.
For the Rotary Switches, I needed 8 circuits (4 quad + & -). Some speaker switches only switch the + side, but if you have a bridging amplifier, switching only the + side could cause damage. This rotary switch is 9 pole, 3 throw (9p/3t) which means it can control 9 simultaneous circuits (quad +- plus a spare) going to 3 different sources or destinations. Very importantly it’s a “break-before-make” or “non-shorting” switch, which means that when a new input or output selection is made, it will break the connection before it makes the next connection – eliminating shorts between amps, particularly. This switch is rated at 3A/350V, which means it’s good for continuous rating of about 35 watts @ 4 ohms or about 42 watts @ 8 ohms. Since it’s the only one I could find with this many poles, and since I doubt I will be running my biggest amp of 110 watts at full blast continuously, I figured it would be fine. These switches are old school – I got mine from Bulgaria on an auction site. Push button switches may be possible, but I couldn’t find 8 pole versions.
The headphone jacks for output 3 are “switched” jacks: when a phone plug is pushed into the jacks, the jacks mechanically lift the signal going to the speakers #3 and send to the headphones. The headphone outs have the same ohm output rating (4,8,16) as whatever amp is sending the output signal, so they will sound best with lower-ohm rated headphones. Note also that the headphone plugs combine left and right neg signals on Speaker #3 out only, so if you duplicate this design, don’t put a bridging amp through this output. The headphone jacks are great for my AV Receiver as it does not have rear headphone outputs.
The knobs are “Fender-type” guitar knobs just cuz like them. The lettering is printed on silver foil printer paper from Michael’s and then spray-sealed and mounted.
Soldering is just a matter of keeping everything straight. A rough wiring schematic and a wiring diagram (attached) for the switch.
It works great. And, no, you can’t buy it and, no, I won’t be making any more!
I would have preferred to use better connection plugs, but I have limited space in my rack, so using these cheaper push connections allowed me to make a unit less than 2 rack units (3.5”) high. If you have the room, use the bigger banana plugs – plus it’s easier to drill a round hole than nibble out rectangular openings for the connections I used which, although intended for PC board mounting, were easy to wrap the wire around and solder.
For the Rotary Switches, I needed 8 circuits (4 quad + & -). Some speaker switches only switch the + side, but if you have a bridging amplifier, switching only the + side could cause damage. This rotary switch is 9 pole, 3 throw (9p/3t) which means it can control 9 simultaneous circuits (quad +- plus a spare) going to 3 different sources or destinations. Very importantly it’s a “break-before-make” or “non-shorting” switch, which means that when a new input or output selection is made, it will break the connection before it makes the next connection – eliminating shorts between amps, particularly. This switch is rated at 3A/350V, which means it’s good for continuous rating of about 35 watts @ 4 ohms or about 42 watts @ 8 ohms. Since it’s the only one I could find with this many poles, and since I doubt I will be running my biggest amp of 110 watts at full blast continuously, I figured it would be fine. These switches are old school – I got mine from Bulgaria on an auction site. Push button switches may be possible, but I couldn’t find 8 pole versions.
The headphone jacks for output 3 are “switched” jacks: when a phone plug is pushed into the jacks, the jacks mechanically lift the signal going to the speakers #3 and send to the headphones. The headphone outs have the same ohm output rating (4,8,16) as whatever amp is sending the output signal, so they will sound best with lower-ohm rated headphones. Note also that the headphone plugs combine left and right neg signals on Speaker #3 out only, so if you duplicate this design, don’t put a bridging amp through this output. The headphone jacks are great for my AV Receiver as it does not have rear headphone outputs.
The knobs are “Fender-type” guitar knobs just cuz like them. The lettering is printed on silver foil printer paper from Michael’s and then spray-sealed and mounted.
Soldering is just a matter of keeping everything straight. A rough wiring schematic and a wiring diagram (attached) for the switch.
It works great. And, no, you can’t buy it and, no, I won’t be making any more!
