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Building a Receiver/Amp Selector Switch

smatchymo

Dec 28, 2013
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Dec 28, 2013
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Hi all,

The only electronic work I've ever done before is changing the bulbs on one of my vintage receivers. My current situation though has caused me to think about the possibility of using a series of switches to select between receivers using one set of speakers. After some research it seems it has been done before using 4pdt switches (see links).

http://audio44.wordpress.com/2013/01/31/diy-amplifier-selector-box/
http://www.stereo.net.au/forums/index.php?/topic/29154-diy-amplifierspeaker-switching-box/

The second link is closer to what I would be using this for. He is using two stereo receivers both with A & B speaker outputs. I would be running two receivers with 4.0 setups. One would be a vintage quad receiver designed for 4-channel LP's. The other a modern 5.1 channel receiver, but only the front and rear speakers would need to run to the switch. Since there is no center channel on the vintage quad (Pioneer QX-949), the center channel on the modern unit (Onkyo TX-SR705) can be connected directly to the speaker. Since I know basically nothing about electronics I was worried about creating something that would damage my receivers. But based off of the second link, I don't think I should be worried. Even though it is assumed only one speaker set, either A or B would be selected at one time, it is possible to select both speaker sets, and if doing so caused damage to the equipment, than I doubt this person would undertake this and also post that everything is working great afterwards. If the person does select both A and B speaker sets on both receivers, then his situation is exactly like mine. The next question is what specs do I need to look for in a switch? The example I'm going off of used 250V 32A, but his receivers were also less than 100W per channel.

Here are the specs of my units, if there is more info needed please let me know. I just didn't know what was relevant.

All speakers - 8 ohms

Onkyo TX-SR705

Front L/R 100 W + 100 W (8 ohms, 20 Hz–20 kHz, 0.08%, 2 channels driven, FTC)
Center 100 W (8 ohms, 20 Hz–20 kHz, 0.08%, 2 channels driven, FTC)
Surround L/R 100 W + 100 W (8 ohms, 20 Hz–20 kHz, 0.08%, 2 channels driven, FTC)
Surround Back L/R 100 W + 100 W (8 ohms, 20 Hz–20 kHz, 0.08%, 2 channels driven, FTC)

Dynamic Power 240 W (3 ohms, 1 ch)
210 W (4 ohms, 1 ch)
120 W (8 ohms, 1 ch)

Output Level and Impedance 200 mV/470 ohms

Pioneer QX-949

Power output: 60W/ch (stereo), 40W/ch into 8Ω (quadraphonic)

Output: 150mV (line)

Any help would be greatly appreciated. Thanks in advance!
 
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