Q&A for me

[Drock]

So I am looking everywhere for great ideas for my build/install. I've hired a graphic designer to draw up some custom designs for my RSD amps. Having a new base done in powder coating then getting custom graphics silkscreened. I'm going to add led's and remove the screens. ( I got a couple of those ideas from another member on the Phorum). I'm having 4X1200.1's and 2X500.4's done this way. I love being able to see the inside of the amps.

Now for my question of the day. I've looked at several nice installs with amps that show off the inside of the amps. But this means that the amps are installed upside down. Is this not bad? Are the sinks not designed to dissipate rising heat. That's why there are fins on top so that air flows through to cool the sink. I know those older amp made allot of heat.

Just curious,


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[audiophyle_247]

The heat is transferred from the mosfets into the heatsink regardless of orientation, and that heat is then spread into the entire heatsink regardless of orientation. The design of the heatsink is to maximize surface area so there is more air to transfer its heat to, also regardless of orientation.

Problems arise where the air is not moving, because the air just gets hotter & hotter and eventually stops cooling because its the same temp, which lets the amp get hotter, and eventually there is no heat transfer between the heatsink & the mosfet because they are both the same temp (heat soak).
As long as there is fresh air available and a means for the heated air to escape, there should be no issues with overheating no matter what orientation.

Hot air rises, so plan accordingly. As long as you can keep the heatsink doing its job, the temps inside the amp (rising off the heatsink surface inside) will be minimal. The same will happen to an amp when mounted right side up too, the internal air begins to heat & will radiate downward from the heatsink until all the air inside is the same temp. Doesnt take long because there is very little air inside an amp and most do not circulate fresh air into their chassis. Keep the exterior of the amp cool, and the interior will gladly put its heat right into the heatsink.

The RSD uses the top & bottom edges as the heatsink, so right side up or upside down the heatsink is pretty much always along the edges.
Cant wait to see these custom RSDs, sounds like they will look cool as hell.

[00goobs]

I love custom anything! You may want to try cold cathode tubes (mini fluorescent) for super bright and even lighting. Also, you could do an MS1000 style with the 2 1200.1s and use custom polished copper bus bars for the power routing. I would love to take on a project like this locally for a show install. The Roadster 66 uses a few heavy gauge wires to do the remotely located power and speaker terminals...

My 1200.1 and a friend's pair of 1200.1s don't get warm after hours of fairly loud playing at 2ohms. I believe the 500.4 would be the one to worry about most on the heat...



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[Drock]

Thanks for your posts. That all makes sense. I was just thinking about when I worked at a local shop many years ago, and every once in a while a kid would come in and want a big alpine amp mounted upside down under the rear deck in the truck. And we (the installers) were told to never do this. Many of the old alpines got very hot.

[Drock]

Ok new question.
Amp specs:

So I know that most PG amps are underrated somewhat. You get different wattages at different voltages and impedances. But what happens when you change the pre out voltages?
Say I have a 2 volt pre out and feed that to an amp do I get the same output from the amp as I do with say 8 volt pre out?
Does the 8 volts increase the output of the amp of does it simply make the amp work less harder to put out the same as 2 volt maxed out?

My reason for asking is this. On an older post I put up, I explained that my H/U has 4v pre outs. Avicz140bh. My signal then goes to my JBL MS8 processor, which has a max pre out of 2.8 volts. I was thinking of installing
a PG one66 line driver after the ms8.
I know that the ideal location for the line driver is as close to the H/U as possible, next in line as it were. But the
MS8 would knock the signal back down. So
If the line driver is installed what does
It do at the amp?

[Drock]

Oh ya, I almost forgot to mention, the design work for the RSD amps is under way. They are going to look sharp. I'm sure most guys on here will be impressed.
New school meet old school. And that's all I'm giving up for now.

[ttocs]

its two steps forward, two steps back and shouldn't hurt anything but ya never know.

[Drock]

its two steps forward, two steps back and shouldn't hurt anything but ya never know.

I know, sometimes I feel I'm going in circles to figure this stuff out. Trial and error I guess. I Just want to get it right the first time.

[Drock]

Hoping someone can help out on this question.
I spent a fair amount of time upgrading the electrical system in the truck. I currently have a 130 amp alt and I am thinking I might do another upgrade to the 250amp alt. my reason is ill be installing 2X elite.4's and 1x elite.1. I think that the amps and other goodies are going to be taxing on the electrical system.
What do you think?
Does the larger alt have any down side on the batts? One guy told me a larger alt could cook the batteries.

[Mr. Wild]

Any alt regardless of size can cook batteries if its output voltage is too high. I don't see why a more powerful alt should put out any more volts than a smaller one.

[ttocs]

as he said if everything is working correctly then there is nothing to worry about. What kind of car is this in(I am getting ready to replace my HO alt in my mustang) and if you need a battery isolator I can hook you up with that as well.

[Drock]

Going into my 2001 gmc Sierra 2500HD. The factory alt was 105 amp. It died a few months ago shortly after installing a couple amps. So I upgraded to a 130 amp alt and added a second batt under the hood in the stock location. My current setup is temp, but I have not tried pushing it yet. And so far it's good. But the new elites are what I'm worried about. And from what I read on a couple web sites my alt is too small for what I need. Problem I'm having is find fact.
If anyone knows how to calculate and figure out what it is I need. That would be very helpful.

[audiophyle_247]

Consider the factory put probably the smallest "acceptable" output alternator they could get away with, so base the 105a as what the vehicle could need. (meaning AC on, lights on, etc etc... all at the same time)
What (if anything) is left over after that your sound system will fighting for. Add up the fuse sizes for the amps you want to run then compare, that will tel you if you need a bigger one or not. lol

130a alt is nothing, two average sized amps could easily eat all 130amps from that alternator. Keep in mind too the alt does not constantly put out power, most modern cars have load circuits that control how much amperage the alt is putting out, so if there is very little stuff running the alt will not be putting out very much. Your 130a alt will most likely be running at 100% capacity while running just about any system with even a single amp at moderate volume levels, because it needs to cover the vehicle PLUS the demand from the amp. Running an alternator at 100% capacity will wear out the brushes & stuff inside far faster than running it at 50~80% capacity, so considering a 250a would not be a bad idea even if you wont need all of it because you most certainly will exceed the 130a one.

The only thing I could think of that an HO alt could do to cook a battery is either overcharging (no load circuit, so running full output constantly when the car didnt need it) or pushing voltages higher than 15~16v.

[ttocs]

yea as he said when I saw the 130 amp I wondered why. Two batteries on that size alt means it has to be running pretty hot to keep them charged.

[Drock]

Thanks guys, I ordered the 250amp alt today. I feel better about doing the upgrade. And considering that unless my phone rings, the stereo is always on. Lol. I should also mention that I have big trailers hooked to truck all the times to. So the two batts are also powering those too.

[ttocs]

who did you go with for the alt?

[Drock]

ALTERNATOR & STARTER in Calgary
$280

[ttocs]

I asked because I too once shopped around and then bought the best deal on a HO alt I could find. It lasted about a year before it went out and I took it down the road to an old timer that has run a shop for a few decades. He rebuild it and said that everything in the alt looked good and rated for heavy duty use except the bridge rectifier diodes and some of the connections between them which is what gave out. $280 for a 250A alot is pretty cheap, it might be worth your time to take it to a local shop to see if they cut any corners or else make sure there is a good warranty on it.

[Drock]

Thanks ttocs, I'll look into it. Good to know.

[Drock]

Just wondering, I'm picking up four elite12's but I did not realize how power hungry they are until talking with a Phorum member. Now I'm not sure that 1 elite.1 would be enough to run them. Was hoping not to spend more $$$ but I think I might need a second. The best subs I'v ever used are my current ti10d's and I don't think they are even in the same league as the elites.
Any thoughts?

[Drock]

Stupid question. If a speaker blows, will it fu-bar a ti amp. Or will the amp just go into protection mode?

[Drock]

Stupid question. If a speaker blows, will it fu-bar a ti amp. Or will the amp just go into protection mode?

[kg1961]

Stupid question. If a speaker blows, will it fu-bar a ti amp. Or will the amp just go into protection mode?

it can what speaker is damaged?

[ttocs]

no protection mode shuts the amp down to keep it from blowing. You should be able to take the speaker wires, short them out and the light will come on and the amp will be fine.

[Drock]

No speakers are blown. I was just wondering, because the ti's have no built in fuses.