Running Fosgate 75HD Amp Indoors

DreadPirate · 2007-10-26 2:42 pm

I'd like to run this amp on my bench with a set of 8 ohm speaks, though those specs are not listed:

http://ampguts.realmofexcursion.com/Rockford_Fosgate_Punch_75HD/

I do have a deep cell battery, but its probably pretty run down. I've read about setting this up with a car charger. Do I just hookup the car charger to the battery then jump from there to the power connections on the unit?

Any thoughts on how good this may sound for a home audio setup?

Perry Babin · 2007-10-26 10:09 pm

Have you confirmed that the amplifier is in good working order?

If you haven't used it 'recently' (<very important), you need to power it up and make sure that both channels play cleanly.

junglejuice · 2007-10-28 7:04 am

So you want to use the Punch as a home amp, what do you intend to use as a source unit?
Plus the 8 ohm speakers will want to be quite efficient as the Punch75 would only put out somewhere in the region of 20 or so watts at 8 ohms stereo....

Mr. Old School · 2007-10-28 2:17 pm

This is what I've been working on for the last couple of years.

Fully active system all 4Ohm speakers

Speakers:

tweters from MTX Black Gold series

mids from Lanzar DC Series and MTX Black Gold

subs from Monocar Raptor series.

Amps:

Lanzar Optidrive 4150

Autotek 300XI

Crossfire VR2000D

Head unit:

Rockford RFX 8140

Processors from Lanzar:

G2M

E30

X3

at the moment the box is a prototype but the sound is still amazing.

The power supply weighs in at 70 pounds and can put out a constant 240 Amps of current.

An externally hosted image should be here but it was not working when we last tested it.

I Am An Idiot · 2007-10-28 7:10 pm

It is not ever a good idea to run a Lead/acid battery indoors. If you have an old computer laying around you can take the power supply out of it and use it. Using 8 ohm speakers are the wisest choice unless you are wanting to spend big money on a power supply.
If you do go the computer power supply route, let us know and we can let you know what you have to do to get it connected. We will need to know if it is an AT or an ATX supply.

junglejuice · 2007-10-29 4:01 am

I Am An Idiot said:
It is not ever a good idea to run a Lead/acid battery indoors. If you have an old computer laying around you can take the power supply out of it and use it. Using 8 ohm speakers are the wisest choice unless you are wanting to spend big money on a power supply.
If you do go the computer power supply route, let us know and we can let you know what you have to do to get it connected. We will need to know if it is an AT or an ATX supply.

Firstly computer power supplies are not regulated so they won't actually provide any real current and maintain 12 volts.
Secondly why would you bother, you firstly need to bring mains voltage down to 12 then step it back up again just to drive the speakers which seems totally pointless and wasteful when a home amp will do the same job with far less waste and less heat.
Thirdly I know that I wouldn't want a car battery in the house with all the associated fumes and ongoing costs.

DigitalJunkie · 2007-10-29 6:30 am

SLA's are sealed,and won't vent gasses into the house (under normal conditions)

I rewound an old Microwave Oven Transformer (MOT) to use as a 12V supply.

http://www.users.qwest.net/~ptaylor/Electronics/MOTpowersupply/MOTPSpage.html

I should update the page someday,but I'm lazy. :clown:

junglejuice · 2007-10-29 6:57 am

DigitalJunkie said:
SLA's are sealed,and won't vent gasses into the house (under normal conditions)

I rewound an old Microwave Oven Transformer (MOT) to use as a 12V supply.

http://www.users.qwest.net/~ptaylor/Electronics/MOTpowersupply/MOTPSpage.html

I should update the page someday,but I'm lazy.

SLA's are even more expensive just to do the job of a home amp....

Clipped · 2007-10-29 8:37 am

i have a couple of old school non HD versions of the punch 75

these specific amps wont run off of some battery chargers, chargers cant provide the current fast enough for these amps,
you'll have to get a dry cell battery or something....maybe a UPS will work , those have 12 volt batts inside.

all you really need to run that amp is a 12vdc 18ah battery, around $30... and hook it up to the charger.

on the battery alone youll get about 30 minutes full volume playing full range on a 15" speaker...or... just turn on the charger when your playing.

cut out the sub bass and the battery will last longer, that way you wont have to turn on the charger and have the ripple come through the speakers.

i use a battery charger and SLA for my test bench...

Clipped · 2007-10-29 12:31 pm

almost frgot, you ma want to hook up a capacitor between the charger and battery to filter the ripple coming from the charger.

i

DreadPirate · 2007-10-30 6:45 pm

Some good ideas here, folks. I need to keep an eye on the microwaves popping up on garbage day. I do have a deep cell battery and charger in the meantime. Caps, huh? I guess these are placed in parallel to the charger leads? What size?

ppia600 · 2007-10-31 1:11 am

It will sound nice if the speakers are really sensitive, and you won't need a large power supply (MAYBE 10 or so amps constant capable to be safe) to produce the 50 or 60 watts the amp will be making. You definately won't need a battery, but a small cap, .5F or so will keep the dc smooth. The punch amps don't like AC ripple, like someone else said.
The good thing is the damping will be nice and the frequency response will be good if the speakers are decent.

DreadPirate said:
I'd like to run this amp on my bench with a set of 8 ohm speaks, though those specs are not listed:

http://ampguts.realmofexcursion.com/Rockford_Fosgate_Punch_75HD/

I do have a deep cell battery, but its probably pretty run down. I've read about setting this up with a car charger. Do I just hookup the car charger to the battery then jump from there to the power connections on the unit?

Any thoughts on how good this may sound for a home audio setup?

ppia600 · 2007-10-31 1:15 am

Mr. Old School said:
This is what I've been working on for the last couple of years.

Fully active system all 4Ohm speakers

Speakers:

tweters from MTX Black Gold series

mids from Lanzar DC Series and MTX Black Gold

subs from Monocar Raptor series.

Amps:

Lanzar Optidrive 4150

Autotek 300XI

Crossfire VR2000D

Head unit:

Rockford RFX 8140

Processors from Lanzar:

G2M

E30

X3

at the moment the box is a prototype but the sound is still amazing.

The power supply weighs in at 70 pounds and can put out a constant 240 Amps of current.

An externally hosted image should be here but it was not working when we last tested it.

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Nice looking setup! How do the subs sound in your towers? I bet you can dim the lights in your living room if you turn it up loud enough, eh??

Mr. Old School · 2007-11-03 2:57 pm

The whole set up sounds great. But I do have to rebuild the boxes with the correct air volume for the Raptor Subs. I had a pair of Phonocar midbasses previousely in there so the volume was correct.

At the moment I have no Sub attached to the VR2000D. 6 Months ago I had 4 10" MTX Black Gold running on the VR2000D and I could shake the lights in the basement, I live on the 3rd floor!!!

The problem I am having on the Sub issue is that I need something that is magnetically sealed so the magnets will not effect the TV picture!! This is turning into a problem. I could not even have the box with the MTX Subs on the same side of the room without turning the TV screen purple!

Running Fosgate 75HD Amp Indoors

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