2 amps sharing speakers
Discussion
Space constraints (orders from Mrs MG) mean I can’t fit another set of floorstanders in the room.
I’ve got a 7.1 surround set up and was considering using the rear floorstanders with my hifi amp as well.
Clearly I don’t want to risk connecting two amps to one another and suffering the consequences - as a result I don’t think I can use a speaker a/b selector box in reverse for fear of somebody using the A+B setting.
Would something like a simple DPDT switch work? What kind of voltages and currents would I be dealing with?
Surround amp is about 190w rms and hifi amp is 80w rms
Thanks for your input
I’ve got a 7.1 surround set up and was considering using the rear floorstanders with my hifi amp as well.
Clearly I don’t want to risk connecting two amps to one another and suffering the consequences - as a result I don’t think I can use a speaker a/b selector box in reverse for fear of somebody using the A+B setting.
Would something like a simple DPDT switch work? What kind of voltages and currents would I be dealing with?
Surround amp is about 190w rms and hifi amp is 80w rms
Thanks for your input
Yes it does- that’s a very good idea - only issue is the AV amp has a room calibration setting that will be out if I’m manually adjusting the volume on the hifi amp- also the surround amp is sometimes used at quite loud volumes and it’s more than twice the rms output of the hifi amp.
Set the hi-fi amp to a level and then perform the calibration - just put it back to this level each time its used for surround sound purposes.
I wouldn't worry too much about the power mismatch, the figures quoted need to be into the same impedance to be comparible, and even then the surround amplifier needs to be actually capable of delivering that power into all channels, which I suspect it isn't unless it has a very significant power supply (transformer)
Try it out, cost to you a bit of time.
I wouldn't worry too much about the power mismatch, the figures quoted need to be into the same impedance to be comparible, and even then the surround amplifier needs to be actually capable of delivering that power into all channels, which I suspect it isn't unless it has a very significant power supply (transformer)
Try it out, cost to you a bit of time.
This 2 Way Speaker/amp switch (biwire) will do exactly what you want.
And if you don't need bi-wiring then this one 2 Way Amp-to-Speaker switch
And if you don't need bi-wiring then this one 2 Way Amp-to-Speaker switch
I have a 5.1 Yamaha home cinema amp, and a Valve amp I use when playing records.
Both amps connect to a switch box. Inside the box, both amps share a common ground (negative) wire to the front floor standers.
The positive wires go via a 6 pin DPDT Double Pole Double Throw Rocker Switch. The middle 2 pins connect to the left and right positive speaker terminals. Top two pins go to one amp L and R channels, and the bottom two pins to the other amp.
Works fine for me.
190W into 8 ohms is just under 5 amps, 25v...so use a decent quality beefy switch. 80W in just under 3.2A
Both amps connect to a switch box. Inside the box, both amps share a common ground (negative) wire to the front floor standers.
The positive wires go via a 6 pin DPDT Double Pole Double Throw Rocker Switch. The middle 2 pins connect to the left and right positive speaker terminals. Top two pins go to one amp L and R channels, and the bottom two pins to the other amp.
Works fine for me.
190W into 8 ohms is just under 5 amps, 25v...so use a decent quality beefy switch. 80W in just under 3.2A
Timothy Bucktu said:
I have a 5.1 Yamaha home cinema amp, and a Valve amp I use when playing records.
Both amps connect to a switch box. Inside the box, both amps share a common ground (negative) wire to the front floor standers.
The positive wires go via a 6 pin DPDT Double Pole Double Throw Rocker Switch. The middle 2 pins connect to the left and right positive speaker terminals. Top two pins go to one amp L and R channels, and the bottom two pins to the other amp.
Works fine for me.
190W into 8 ohms is just under 5 amps, 25v...so use a decent quality beefy switch. 80W in just under 3.2A
It's plausible that connecting the speaker -Ve outputs of two amps together might cause issues in various ways.Both amps connect to a switch box. Inside the box, both amps share a common ground (negative) wire to the front floor standers.
The positive wires go via a 6 pin DPDT Double Pole Double Throw Rocker Switch. The middle 2 pins connect to the left and right positive speaker terminals. Top two pins go to one amp L and R channels, and the bottom two pins to the other amp.
Works fine for me.
190W into 8 ohms is just under 5 amps, 25v...so use a decent quality beefy switch. 80W in just under 3.2A
Not all amps have the speaker -ve grounded in the amp (class D amps, some transformer output valve amps, bridge amps.....) and sometimes connecting 'grounds' together at random can do odd things.
Some amps don't even have a connection to mains earth.
A 4 pole switch would be technically safer.
Multi-pole switches of decent current rating don't grow on trees, it might be easier to source relays.
A 2 pole switch for the left channel and the same again for right is a good option.
Many amps of course have speaker protection relays so if only one amp is ever switched on at a time, you don't need a switch at all.
But please don't do this!
Assuming you're not going to switch the switch while any amp is playing loud, you can probably get away with a low-rated switch, it's the making and breaking that kills switches, not 'carrying' current.
Switching under load won't be a kind thing to do to an amp or a speaker.
Must be 'break before make' or 'non shorting'.
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