Need a 120 volt relay

[Mortimer Schnerd]

I'm looking for a cheap 120 volt relay to use with my stereo system. I've got a receiver that has pre in/main out jumpers and so I've added a second power amp to it which is a lot more powerful that what's already built into the receiver. I'm actually powering three rooms of speakers (8 speakers all told); two sets on the receiver's power amp and 4 speakers in my bedroom off the external power amp.

I want the power to the amp to come on whenever I power up the receiver but it's a PITA to get to because of the way it's physically installed.

The AC outlet on the back of the receiver is only rated for 100 watts max. The power amp can draw up to 11 amps so the receiver's AC outlet isn't going to work.

So what I think I need is a relay. The switched outlet on the back of the receiver can power the coil and then the relay can handle the power requirements of the external power amp.

So where can I find such a thing? Ideas?

Mortimer Schnerd, RN mschnerd at carolina.rr.com

[jeff_wisnia]

Rat Shack has 'em if you don't have any other source. You can prolly find a socket for one there too, or just cut both ends off an extension cord leaving a few inches of wire on each and solder directly to the relay's lugs.

Jeff

[jeff_wisnia]

Yeah, Shack has a socket too, but you'll still have to solder to it's lugs.

Jeff

[jeff_wisnia]

Oh yeah, I forgot to say wire both sets of normally open contacts in parallel, that should take care of the 11 amp peak load OK, since they prolly won't be switching at peak draw times anyway.

Jeff

[Mortimer Schnerd]

That one is only good for 10 amps. My amp can draw 11 so I'm really looking for one rated for 15-20 amps.

Mortimer Schnerd, RN mschnerd at carolina.rr.com

[Big Bob]

[John Grabowski]

*I'm thinking that maybe some plug-in modules from SmartHome would work for you.

[Jon Danniken]

Get a contactor from Ebay, maybe something like 370220418231

Jon

[The Daring Dufas]

There is a wonderful outfit called FUNCTIONAL DEVICES, INC. which manufactures some of the most versatile relays I've ever used. I wish I owned stock.

TDD

[John Gilmer]

OK.

Above 10 amps or so, it's call a "contactor."

You can get then at an electrical supply house (with either 24 volte or 120 volt coil). If you are cheap, you can "salvage" them from a microwave oven or a central A/C. It's kinda fun to take apart a dead microwave oven. You get a transformer suitable for making your own electric chair among other things. The magnets are a source of some amusement also.

"Contactors" have either screws connections or a "spade" male leads. You can get the connectors at R/S. Put the whole thing in a box to keep your cat from getting fried.

Since you only need 11 amps you can consider getting a two pole relay from R/S with each pole rated for 10 amps. Wire the poles in parallel and you have a 20 amp relay.

[cjt]

... except that one side will invariably connect/open first, so that the load won't be equally shared and it'll burn out faster than a device that's designed for 20 amp service.

[ransley]

Check standby load, it might save you quite a few watts putting everything on a power strip and cutting power completely when not in use. I dont know your set up but understand Ohms and polarity when wiring speakers, improper ohms can damage some amps, reversing polarity can cut out bass frequencies.

[Hipupchuck]

If Radio Shack don't have one try All Electronics web site.

[Hipupchuck]

Factory Mation is a good place for contactors and time delay relays.

[Mortimer Schnerd]

I thought about that last night. I think I found the answer with a

120VAC 15 amp double pole single throw relay from WW Grainger.

Thanks to everyone who answered. There were several possibilities but no other cost only $12.80.

I'm off to Grainger's....

Mortimer Schnerd, RN mschnerd at carolina.rr.com

[Mortimer Schnerd]

I have a pretty good understanding of impedance and polarity. Not to worry; I've been running this combination for some time now with a different receiver. This new one is the same brand but has the pre in / main out jumper that the other didn't. I had to use the tape out on the older receiver to feed the external power amp and then control the volume with the two pots on the front of it. It was not the ideal situation but I'm getting there rapidly now.

I have used the external power amp exclusively for the four 12" three ways that I have in my bedroom for some time now. Each pair is wired in parallel. The receiver fed the other two rooms with a pair of speakers in each. So I could control bass/treble in the other rooms but not my bedroom. I could only control volume and balance there. I still won't be able to control fade but them's the breaks.

This relay will solve my last annoyance.

Mortimer Schnerd, RN mschnerd at carolina.rr.com

[Mark Lloyd]

I got one of those relays (from Radio Shack) once. The relay itself was rated for 10A. The package it came in said 15A.

[Red Green]

jeff_wisnia wrote in news:ze2dnVfyDPYr-NDXnZ2dnUVZ [e-mail]:

prolly?

Come oooooon Jeff. You know too much to be 15 yrs old :-)

[JIMMIE]

XnZ2dnUVZ [e-mail]:

I did something very similar to what the OP wants using a DPDT relay wih the contacts wired in paralell.

Jimmie

[David Nebenzahl]

On 7/2/2009 6:44 PM Mortimer Schnerd spake thus:

Here's just what you need, for only $2.50:

This one's rated at 40 A, so you should have no problems with it.

And forget Radio Shack, as some other posters have suggested. They're useless.