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Trigger circuit for pro amps

1045 Views 22 Replies 13 Participants Last post by  kwill
So I'd like to entertain the idea of using pro amps in the theater I'm planning. The bang for the buck factor is off the charts! But the lack of triggers on these things is a big pitfall in my opion. So the question for all you geniuses out there is, how difficult would it be to build a 12v trigger interface with 120v outlets?? You catch my drift?? A small enclosure with a couple receptacles and the trigger circuit?? Surely the circuit itself can't be that complicated, I'm assuming it's not much more than a relay. Am I off in left field here fellas??
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I purchased a Panamax MC8 Pro and used it to turn on my Pro Amps once it senses a signal from my Yamaha receiver. Cost was about $85 shipped.

I have some threads in the htpc forum about this.

There are some devices like this from xantech and niles. They have delays and everything. Just a bit pricey, around $170-250 depending on the vendor.
EXTREMELY easy. Decide how many sockets you want. Buy that many 15A (or more) 12VDC relays. Hook up the mains hot to all of the relays, and run hot wires from each socket to the terminal of the corresponding relay that has voltage when the relay is activated. Run the mains neutral and ground wires to all sockets w/o relays. It's really a very simple thing to build.

If you are not electronically inclined, I can walk you through making one. It should be under $15 to make plus the cost of the enclosure, which can range from a few dollars to a hundred or more. One could also modify a regular power strip, or make a 1-in 1-out box that you could plug a power strip into. Both of those would be very cheap for the enclosure.

I don't mind making them for you for cheap. If you're interested, point me out an enclosure you want (ship one to me, or tell me what to order from Radio Shack or Mouser or similar reputable dealer, or for the power strip or 1-in 1-out version, I can just grab something cheap) -- I can probably start around $25 to $30 shipped to the US.

This offer is open to everyone, by the way. If you are reputable (either well known around here, or can provide me an Ebay or Heatware account with good feedback), then I could ship it to you before you paid me, so you can see how it works.

I can also add fixed or adjustable delays on each socket for not too much more. (and if anyone wants to make one of these themselves, feel free to ask me how do make a delay circuit)

You can use a single relay for all sockets if you don't want delays, but I'd use a 30A or more relay for it.
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I'd recommend a single solid state relay with zero crossing switching. They can be had in 10 to 100 Amp capacities, with 3 to 48V DC control inputs.
SSRs get quite pricy, though.
$5.00 used, $80.00 new....mechanical realys with 30 Amp contacts aren't cheap either...and they're electrically noisey.
Originally posted by T_trip
I purchased a Panamax MC8 Pro and used it to turn on my Pro Amps once it senses a signal from my Yamaha receiver. Cost was about $85 shipped.


You plug the M8C Pro right into the receiver?
I've got an extra Panamax 1000+, PM me if interested.

Does that Panamax have a 12V trigger?
Weird, I thought my post was pulled, now it's back.

Anyway, j_f, IPM'd you, I believe so.
I have added some directions to my website at www.antialiased.net

I will try to add pictures to the guide later. If you have any questions, you can privmsg me, and if I think it's worth it, I will fix/add to my guide.

Note: if the page doesn't work, then I'm probably doing something to my server, as I am now.
Yep - the instructions say "the sensing input is desiogned to be controlled by either 120 VAC or 12 VDC".

I tried it with batteries (two dead 9 V in series) and I could hear the relay actuate (only one polarity works).
Thanks for making this info available to the forum Donoman. This is one project I will likely try soon. One question, though.

I have 2 pro amps that I want to be able to turn on with my H/K receiver (switched outlet). The manual warns not to connect an amp to the switched outlet of the receiver due to its draw. I assume this circuit accounts/ compensates for that? Sorry if that sounds like a dumb question, I just don't want to fry my receiver.
Switched output is when the receiver has extra (output) 120V sockets on it. This project is only limited by the capacity of the parts you use.

So my H/K has a switched output (120V) socket. I want to be able to turn on my pro amps using the receiver.

Would the parts that you suggest in your page (i.e.) 30 amp automotive relay,
I also went the panamax route... using the trigger on my 3805 to the power strip, which has 4 trigger outlets.
Yes, the stuff I recommend is actually overkill for a 15A circuit.
Forget making a relay box - the labor can't be justified when Sears sells a current sensing outlet trigger for around $20 bucks. Look here:

Just plug your pre/pro or a source into this and the amps into the triggered outlets. It's remarkable that they've come up with this thing for so cheap...but there it is. Hell, you can even order 'em online - talk about simple!
Originally posted by M NEWMAN
Forget making a relay box
You're taking all the damn fun out of it!!! :D
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