How to effect 12V triggers for multiple amps with staggered delays

D

DS-21

Full Audioholic
I want to set up a delayed triggering system, with staggered delays, for my equipment.

I'm looking for the most cost-efficient way to get there, without DIYing an electrical box.

Here's the relevant equipment:
-Anthem MRX 300 AVR (has switched outlet and 12V trigger)
-2x4 miniDSP in a Box powered by an old phone charger (for subwoofers)
-Sherwood Newcastle A-965 Class AB mains amp
-2x Dayton SA-1000 Class G subwoofer amps (Technically one of them is badged "Snell SPA-750." Same amp, though.)
-Gallo MPS150 Class AB subwoofer amp
-And a miniDSP 8x8 in a box, when they release it, for the mains. That's why I'm not just using the AVR's amps.

I want staggered delays for two reasons.

First, I want to mitigate the miniDSP turn-on thump in the subs, by turning it on before the sub amps come on. I was thinking I could effect that by plugging it into the MRX's switched outlet. (The 8x8 has a trigger with delay built in.)

Second, it strikes me, given that the four amps' combined output is well over 3kW, that I might not want them all charging their capacitors at once. And the AVR takes about 11 seconds to boot up, so maybe the mains amp should come on in 5s, and the sub amps should come on another 5s hence.

The $40 Emotiva box that has been discussed here looks neat, but doesn't seem to be able to stagger the triggers.

So, back to the question on top of the page: what's the most economical way for me to safely do what I want to do, without having to DIY electrical circuits?
 
avnetguy

avnetguy

Audioholic Chief
So, back to the question on top of the page: what's the most economical way for me to safely do what I want to do, without having to DIY electrical circuits?
Does that include no low voltage (12v) DIY electrical circuits?

Steve
 
D

DS-21

Full Audioholic
Does that include no low voltage (12v) DIY electrical circuits?

Steve
Well, if it's really quick to do and orders of magnitude cheaper than a commercial solution, perhaps I'd be amenable to DIY. But I'd prefer a commercial solution.
 
walter duque

walter duque

Audioholic Samurai
I use a power sequencer for my power amps. Triggers are staggered. BTW just checked your signature, what's that Anthem doing in you system?
 
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TLS Guy

TLS Guy

Seriously, I have no life.
I want to set up a delayed triggering system, with staggered delays, for my equipment.

I'm looking for the most cost-efficient way to get there, without DIYing an electrical box.

Here's the relevant equipment:
-Anthem MRX 300 AVR (has switched outlet and 12V trigger)
-2x4 miniDSP in a Box powered by an old phone charger (for subwoofers)
-Sherwood Newcastle A-965 Class AB mains amp
-2x Dayton SA-1000 Class G subwoofer amps (Technically one of them is badged "Snell SPA-750." Same amp, though.)
-Gallo MPS150 Class AB subwoofer amp
-And a miniDSP 8x8 in a box, when they release it, for the mains. That's why I'm not just using the AVR's amps.

I want staggered delays for two reasons.

First, I want to mitigate the miniDSP turn-on thump in the subs, by turning it on before the sub amps come on. I was thinking I could effect that by plugging it into the MRX's switched outlet. (The 8x8 has a trigger with delay built in.)

Second, it strikes me, given that the four amps' combined output is well over 3kW, that I might not want them all charging their capacitors at once. And the AVR takes about 11 seconds to boot up, so maybe the mains amp should come on in 5s, and the sub amps should come on another 5s hence.

The $40 Emotiva box that has been discussed here looks neat, but doesn't seem to be able to stagger the triggers.

So, back to the question on top of the page: what's the most economical way for me to safely do what I want to do, without having to DIY electrical circuits?
You can't. The only way I can think of is to use LM series timer chips to throw electronic switches in sequence. These chips are quite simple to design with, but you would have to DIY a board and provide a power supply.
 
P

PENG

Audioholic Slumlord
Second, it strikes me, given that the four amps' combined output is well over 3kW, that I might not want them all charging their capacitors at once. And the AVR takes about 11 seconds to boot up, so maybe the mains amp should come on in 5s, and the sub amps should come on another 5s hence.
I am not sure if you have them all from the same outlet. Even if you do, consider that charging the capacitors does not take very long at all. I am too lazy to do any calculation now but I am pretty sure it will be no where near a couple of seconds, if it takes a longer time by design, then the current won't be very high. Discharge could take longer but I know that's not your concern anyway. To me the advantage of staggering them would be to avoid the potentially excessive transformer inrush current and that depends on the design of the specific amp. Of all my amps, only one of them would cause lights to dim and it is one with the lowest output (200X2). The other ones apparently have built in soft start features.

The initial inrush current happens when a power transformer is powered up when the input voltage sine wave is at exactly 0V with no load connected to the secondary winding (output). The maximum possible peak also depends on the polarity of the residual magnetism in the winding but that should only be a factor if it is powered off and on within a short time.

Theoretically transformer inrush current could be as much as 12 times of its rated current (input side in this case). It could be even higher depending on the specific design. So a 1200 VA transformer could draw over 100 A or higher during the first 0.1 second or less. I really wouldn't worry about that at all due to the short duration, unless you have other voltage dip sensitive loads connected to the same outlet. So I think you may really have only one reason, not two.

The $40 Emotiva box that has been discussed here looks neat, but doesn't seem to be able to stagger the triggers.

So, back to the question on top of the page: what's the most economical way for me to safely do what I want to do, without having to DIY electrical circuits?
If you google very hard and cannot find one you may have to go the DIY route. I think mostly likely you won't find one and I wish you luck.
 
D

DS-21

Full Audioholic
I use a power sequencer for my power amps. Triggers are staggered.
Interesting. Never heard of those before. Did it replace your power strip, or do you plug it into a strip?

Yours looks like a vintage piece. Cinepro's website only lists a "power product" for 30A circuits. Do you happen to know of a good new power sequencer? I live in a part of the country with lots of lightning, and when I was in 6th grade I was home along watching TV when lightning struck, killed the TV and VCR, and melted a Panamax surge protector to the carpet. So I'd want something that carried some surge-protection warranty as well. Or at least wouldn't void the warranty on the strip I'm using.

BTW just checked your signature, what's that Anthem doing in you system?
It was my AVR, but now it's just doing pre-pro duties: source switching, room correction, volume control, etc. The Sherwood A965 is actually just a ginormous hulk of 7-channel amp. You perhaps thought it was their AVR with Trinnov room correction? That's A-972 or something like that. Perhaps a picture of my "rack" (aka the space under the daybed against the wall in my living room - I prefer my audio gear out of sight) will clear things up:

Why the separate mains amp, given my stated position on the them? When I move, I plan to take my mains active, with the miniDSP 8x8 doing crossover duties. So I'd been looking on and off for a 6+ channel amp. I happened on a killer deal for a new, still-wrapped-up one locally, with a receipt from an authorized dealer included. So even though I'd prefer a more compact, cool-running, and energy efficient Class D unit, and honestly wouldn't need more than 30-50W/channel, instead I ended up with a powerful 80lb, 18" x 18" x 8" dual transformer Class AB space heater... (It does, for the record, carry a UL safety certification label on the back!) And based on Dr. Rich's review of the circuit design (see link, supra), I suspect it'll be my mains amp for a while. At any rate, should I sell it later for a more efficient and compact amp, I'll be able to pass a great deal onto someone new.

I bought it in anticipation of running my front three mains with active crossovers (need six channels for that) when I move in few months. But after testing it to make sure every channel worked and was quiet...I decided it would be less effort to put it in my "rack" it than to pack it up.



Note that speaker wire positive leads are keyed with heat shrink conforming to the CEA-865B color code - one of those little things that makes putting things together go so much more quickly! For some reason, the binding posts on this amp are a little small. I'll probably scrounge up some of my spade lugs and do spade connections when I move. But for now, whatever. The bananas ("Nakamichi" Z-shaped ones with insulated plastic barrels) seem stay in just fine.


It looks a bit like a left tackle next to two scat-backs and a fullback, doesn't it? And yes, I plan on making interconnects that fit without too much slack, and using a shorter trigger lead. I just used stuff I had on hand for now, but I'm OCD enough to want no more than ~6" slack. Obviously, that won't have any sonic impact, but it'll look better.


Of those five (well, 4.2 maybe, considering the relative size/mass of the miniDSP) ugly boxes, here's all that's visible in the room. I'd get an IR blister and hide the AVR too, if my ca. 2009 TV had HDMI-ARC. But it doesn't, so no on-screen display over OTA HDTV. I'd rather be able to crane my neck to the side and squint to see the volume level than not see it at all. :)



True, the fact that I had to lift its (even more gigantic, with a solid 4+" of space around every side) box up about 5' in my storage closet, or, in the alternative, rearrange everything, had a little to do with my decision to just use the damn thing. :)
 
avnetguy

avnetguy

Audioholic Chief
Of all my amps, only one of them would cause lights to dim and it is one with the lowest output (200X2).
Actually that's a pretty good and simple test to see if you really need a staggered start up. If you're not causing any significant dim to an incandescent light, as usually seen with starting high current electric motors, why bother.

Steve
 
walter duque

walter duque

Audioholic Samurai
[
QUOTE=DS-21;868871]Interesting. Never heard of those before. Did it replace your power strip, or do you plug it into a strip?

Yours looks like a vintage piece.
As you can see all my stuff is vintage, I got in this game early. I am vintage too, so it fits my needs.

It was my AVR, but now it's just doing pre-pro duties:
My mistake, I thought I've seen a Pre-pro in there somewhere. BTW that's a nice AVR.
 
Rickster71

Rickster71

Audioholic Spartan
I agree with Peng.
How many different circuits are you using?
If the circuit or circuits don't trip when you're using them, they aren't going to trip from inrush current.
The solution I use for my sub, is to unplug it after every use.
That's since you mentioned you wanted the 'most cost effective' way.
Just a thought.
 
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mtrycrafts

mtrycrafts

Seriously, I have no life.
I want to set up a delayed triggering system, with staggered delays, for my equipment.

I'm looking for the most cost-efficient way to get there, without DIYing an electrical box.

?
Not sure if this would work for you
APC AV 15 Amp G Type Rack Power Filter, 120V
While the page doesn't specifically mentions delay feature, it does have it.
It has 4 different time delayed turn on capability that you program how much delay you want and has 8 outlets.

I use it for convenience sake. It has some nice light on the front that lets you know if it overloads on turn on.;):D
 
P

PENG

Audioholic Slumlord
Not sure if this would work for you
APC AV 15 Amp G Type Rack Power Filter, 120V
While the page doesn't specifically mentions delay feature, it does have it.
It has 4 different time delayed turn on capability that you program how much delay you want and has 8 outlets.

I use it for convenience sake. It has some nice light on the front that lets you know if it overloads on turn on.;):D
Very interesting, APC has answers for most things! I probably want one.:D
 
D

DS-21

Full Audioholic
Not sure if this would work for you
APC AV 15 Amp G Type Rack Power Filter, 120V
While the page doesn't specifically mentions delay feature, it does have it.
It has 4 different time delayed turn on capability that you program how much delay you want and has 8 outlets.

I use it for convenience sake. It has some nice light on the front that lets you know if it overloads on turn on.;):D
Thanks! I have a feeling I'll be ordering one of those, even though it turned out to be a problem easily kludged through: the MRX-300 takes about 10sec to boot up, so if I set the trigger to go after a 5s delay and set the three sub-amps to signal-sensing turn on, the lights dim if anything less than they did with the sub amps on signal-sense and a Denon 4308 providing switching and power.
 
mtrycrafts

mtrycrafts

Seriously, I have no life.
Very interesting, APC has answers for most things! I probably want one.:D
Thanks! I have a feeling I'll be ordering one of those, even though it turned out to be a problem easily kludged through: the MRX-300 takes about 10sec to boot up, so if I set the trigger to go after a 5s delay and set the three sub-amps to signal-sensing turn on, the lights dim if anything less than they did with the sub amps on signal-sense and a Denon 4308 providing switching and power.
It is a bit confusing in their manual, for me. It has outlets that are always on, switched when you turn it on and 4 delayed possibility with delay 2 having 2 outlets.
On turn off it is the reverse of turn on.
The LCD display window can show one of several event: line voltage, amps, etc.
A neat, functional toy:D
 
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