New 12 volt amp rack for remote location work...

[jcmbowman]

No fight necessary. And I definitely concur on those who insist on bragging.

Truth be told - my litums test is generally limited to those on the DIY and local level. I just find myself gravitating towards others who are equally obsessive about good sound, and in my experience, good sound is something to be experienced at home, in the car, and at gigs.

It's just one of many indicators I use to weed out the hot air from the people who really care.

[djmarcelca]

If you want to use that little amp pack and running it off 110 volt grid power....

Just go to your local computer parts supplier tigerdirect.com for example and purchase a computer power supply. For people that didn't know a computer runs on 12 volt DC or 5 Volt DC depending on which connector you chose. You can get them quite powerful as well 1600watts for example

Advantages to this..

Smooth DC voltage output.
Super high power
Ultra Quiet
Cheap as hell.

No need for any more that a 6 inch cube box, & a strong car amp and about 4 or five fans to keep the amp cool and the P/S as well

I built mine and about 4 other DJ's DJ computer for Video mixing, and karaoke use.

[Sydney]

and purchase a computer power supply. For people that didn't know a computer runs on 12 volt DC or 5 Volt DC depending on which connector you chose. You can get them quite powerful as well 1600watts for example

Advantages to this..

Smooth DC voltage output.
Super high power
Ultra Quiet
Cheap as hell.

I would be curious to the details of your implementations...

Many of the computer supplies are primary switching power supplies with power switches arranged in a half-bridge configuration, many with a switch frequency just outside the audio band.
The outputs can drive the multiple 8 A (+12 V) sections.
I have not seen an ammeter reading using the "yellow/black" circuit to determine how much power is available. The wire gage utilized in a PS has inadequate ampacity for high power.
RE: http://www.powerstream.com/Wire_Size.htm
For #18 it is 16A for #22 it is only 7A. Any amperage beyond that runs the risk of burning the wire.
That is the reason 12V power systems have to have large gage wire if it is run more than a foot or so.
Coincidentally, I am replacing a computer PS that had a bad 5V section. I had been pricing replacements from TD. For a 700 watt PS approx $90, for a 850watt supply $160: the price increase is not linear. What does a 1600 watt PS cost?
A lot of 12V transformers and fully regulated power supplies and bench supplies can be found at vendors of industrial surplus ( AllElectronics for example ).
A fan-less switching 12V 29A PS can be had for as little $60. Hookup is via a chassis barrier strip, not a wiring harness. It is switched @ 25Khz however.

[djmarcelca]

Sorry be slow getting back.

Read the wiki on PSU:
http://en.wikipedia.org/wiki/Computer_power_supply

They are 12v DC continuous voltage supply. mounted in you rack it would be a decent conversion for using that rack on standard 110v AC.

Mind you would have to spend some time reading the specs on the individual PSU's to get the continuous power rating. Also they are remote switch controlled so, you would need a small 5v switch to turn the PSU on.

[Sydney]

That link contained this:
"The power rating of a PC power supply is not officially certified and is self-claimed by each manufacturer.[1]A common way to reach the power figure for PC PSUs is by adding the power available on each rail, which will not give a true power figure. This means that you cannot use the PSU maximum rating on one rail, but only as a total. Therefore you can overload a PSU on one rail without having to use the maximum rated power."

Also further down:
"The ATX12V 2.x and EPS12V power supply standards defer to the IEC 60950 standard, which requires that no more than 240 volt-amps be present between any two accessible points. Thus, each wire must be current-limited to no more than 20 A"

This is what I was referring to in my post
Ohms law: 240 watt power supply MAX, with about 120mv ripple.

[rjohs]

RubiconProSound,

This is a great idea! How has it performed now that you have had it for a year? What kind of run time and output?

I'd love to see some internal photos and maybe a wiring diagram to incorporate the farad capacitor that jcmbowman suggested.

Rich

[CafSentryGnome]

you could always do what i do with my car when im using it for shed music (in the next shed) hook it up to a 15amp battery charger.

[RubiconProSound]

RubiconProSound,

This is a great idea! How has it performed now that you have had it for a year? What kind of run time and output?

I'd love to see some internal photos and maybe a wiring diagram to incorporate the farad capacitor that jcmbowman suggested.

Rich

It's worked great! I'm an avid 4 wheeler and this rig comes with me out on the trail quite a bit. I've hooked it to my deep cycle as well as a regular car battery (just pop the hood and clamp on to the battery...) It's had my T18's and my T30's hooked up to it and everyone is always amazed by the output. I just got back from an off road race out in the desert and used this rig at the back of my trailer to provide tunes.

the race: http://www.kingofthehammers.com/

As far as run time is concerned I've run it at "background" levels (90 dB +/-) for about 16 hours with just the iPod before needing to recharge the deep cycle. With the deep cycle and the power inverter running the laptop I'd have to guess about 3~4 hours at war volume (105+ dB average) I say "guess" because I never wanted the battery to go dead on me in the middle of spinning so I usually "topped" the battery off every 2 hours or so by starting the car for a few minutes. The size of the deep cycle will also make a difference on run time.

I'll try to post up some better shots of the interior. The stiffening cap would just be installed across the hot and ground...

[SeisTres]

For the car audio post - They stole my $40 cassette stereo (which I would use and adapter for my mp3) so no I put a 2.1 creative computer speaker system in the car and now plugs into my mp3 output. Like that, I actually got a sub in the car, hooked the system (12v) to the car, and the tops got crossovered, not just the full signal. Tried th AT but didn't even bother hooking it up, that thing took up ALL of my trunk

And for the computer PSU post - while the PSU are rated for certain wattages, the major portion doesn't go into the 12v, it actually go into the 5v for the processor and all the digital stuff. the 12v is just to power the electric motors on the drives. That being said, unless you're going to power a 20w/channel amp, or simply a car eq or xover, it is of little use. Not to mention everything else sydney pointed out. Also, they don't like like it when no power is being draw which will cause it to go into protect mode. THAT being said, I'm still going to try to use it to make a monitor amplifier. along a with a car crossover when I dont want to bring out my DRPA out to play. If that doesn't work, I still have the 12v/2.9A transformer left over from creative speaker system which is currently in my car

[pyroja]

And for the computer PSU post - while the PSU are rated for certain wattages, the major portion doesn't go into the 12v, it actually go into the 5v for the processor and all the digital stuff. the 12v is just to power the electric motors on the drives. That being said, unless you're going to power a 20w/channel amp, or simply a car eq or xover, it is of little use. Not to mention everything else sydney pointed out. Also, they don't like like it when no power is being draw which will cause it to go into protect mode. THAT being said, I'm still going to try to use it to make a monitor amplifier. along a with a car crossover when I dont want to bring out my DRPA out to play. If that doesn't work, I still have the 12v/2.9A transformer left over from creative speaker system which is currently in my car

My first post on these forums and I'm gonna show how much of a computer nerd I am

It used to be true (and may still be so for cheap PSUs) that most of a PC PSU's wattage went to the 5A rail(s), A) to beef up the 'watts' number they could claim, and B) For the reason you stated. Back then, there wasn't a lot more than HDDs, Fans, and optical drives pulling much power from the 12v side of things.

Nowadays, with a quality PSU, the 12v side is made fairly beefy. Overclocked processors, insane video cards, and high power cooling systems have made this a necessity for the high-end PSU market. For example, in my gaming system, I have a BFG ES-800 (Named for its 800watt rating). It has 3.3v, 5v, and 12v rails. The 3.3v and 5v rails combined only amount to 170w total, whereas the 4 12v rails can provide up to 22A (for #1 and #2) and up to 36A (for #3 and #4). That accounts for a max of 780w on the 12v side. Now, sure, you won't be getting along very well if you max out the 12v rails for long, but the possibility is there for pulling some decent power.

If you want to entertain the idea of using a 12v PSU for certain things, and you want to know what's good out there, http://HardOCP.com does reviews for all manner of high-end PC components. In particular, they have a very rigorous testing process for PSUs. Rest assured, if a PSU passes their test unscathed, it's a quality unit.

Just, uh... Some food for thought

Also, question: I looked up those little amps you're using, and it looks like they have built-in crossovers. Of course, in true car audio fashion, the manual only describes them in the most vague of details. Did you make use of these x-overs? Do they do the job well enough? Man, it'd be nice if RoadMaster gave a half-decent spec sheet for these things