Do i need class D?

[bump465]

alright so I had a zapco 1000.4 that id thermal protect in about 45mins. Im from az and never had my amp thermal protect on me. (in Co. now) I thought the amp was on the fritz or just to old to function for extended periods. Replaced it with 2 audison lrx amps, (these ones)

Audison LRx-4.300 (lrx4300) High-fidelity, 4-Channel LRx Series

Audison LRx-6.SR (lrx6sr) High-end, Car Theatre 6-Channel

Now these amps last about an hour then the 4 channel thermals then the 6 channel 5 mins later... wtf.

my sq3500 never thermals.

All amps are in the spare tire location in the trunk so they are basicly getting zero airflow. the sq amp is basicly encased in a wooden box and the audison are on top of it, but i doubt that much heat travels through the 1/2in wood for my sq to be heating the audison.

Do i simply need a D block for vocals if i wish to mount in this location? or should i just "underdrive" a much more powerful a/b amp?

I really dont want to have to rewire everything to mount the amps elsewhere.

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[cthedinger 10+ year member]

The first thing I would check is make sure all the wires to your 4 channel are secure and double check your ground for that amplifier. Class AB amplifiers do have a tendency to get a lot hotter than Class D.

If you are looking for a nice Class D 4 channel check out this

https://www.ct-sounds.com/products/amplifiers/at-series/at-125-4d.html

 

[bump465]

my grounds definitely came to mind for the reason of heat.

however in my experience a bad ground will make the amp cut out at random.

These a/bs are stable while im beating the **** outta the frame of my car its only after an hour at full tilt I have problems, nothing random about it.

That lead me to believe the ground isnt an issue. It is grounded to a thinner peice of metal that I would like, but as long as my DMM reads 0 ohm when on battery + and ground location, its a solid ground, right?

ill check to see if I can wiggle it by hand though, good place to start.

 

[cthedinger 10+ year member]

my grounds definitely came to mind for the reason of heat. however in my experience a bad ground will make the amp cut out at random.

These a/bs are stable while im beating the **** outta the frame of my car its only after an hour at full tilt I have problems, nothing random about it.

That lead me to believe the ground isnt an issue. It is grounded to a thinner peice of metal that I would like, but as long as my DMM reads 0 ohm when on battery + and ground location, its a solid ground, right?

ill check to see if I can wiggle it by hand though, good place to start.

Yeah if it only cuts out after an hour of play it is probably that your class ab amplifier isn't getting enough ventilation since it is in the tire well.

 

[bump465]

super frown. so would a 2kw a/b amp driven at ~1000watts put of the same amount of heat as a 1kw a/b driven at 1000w? I might have to start looking at class D's. Are there any high powered 4ch D blocks - compariable to say an hcca 2000.4/twisted 2k15? that ct looks nice but 125@4 isnt going to cut it for me.

 

[cthedinger 10+ year member]

super frown. so would a 2kw a/b amp driven at ~1000watts put of the same amount of heat as a 1kw a/b driven at 1000w? I might have to start looking at class D's. Are there any high powered 4ch D blocks - compariable to say an hcca 2000.4/twisted 2k15? that ct looks nice but 125@4 isnt going to cut it for me.

Honestly from what I have found it when it comes to Class AB amps it really depends on the models. Some models don't seem to get hot at all while others tend to get super hot. Running a 2000w rms class ab amplifier at half power would for sure be less likely to go into thermal protect then if you were to run it all full power.

This 4 channel won't be in stock until December but it does 200w x 4 at 4 ohms or 350w x 4 at 2 ohms

https://www.ct-sounds.com/products/amplifiers/at-200-4.html

 

[garychoffmann 10+ year member]

Can you ventilate the area they are in? I mounted in the spare tire area and cut 2 holes for a push pull fan configuration. My box sat directly on the fans but I raised it 3/4 of an inch with mdf strips and it solved my heating issues. This was an old school setup of orion's so they got plenty hot.

 

[hispls 5,000+ posts]

Interestingly enough we did an older AQ 3500D in a friend of mine's spare tire well with a couple batteries and it never overheated. Class A/B gets super hot period. Get them mounted somwhere where they can get some air (even that may not solve your problem depending on the amp) or start shopping around for full range class D.

I can't imagine what drivers you have that need more than 125W per for fronts. What components do you use and how much power do you think you need for them?

 

[bump465]

Interestingly enough we did an older AQ 3500D in a friend of mine's spare tire well with a couple batteries and it never overheated. Class A/B gets super hot period. Get them mounted somwhere where they can get some air (even that may not solve your problem depending on the amp) or start shopping around for full range class D.
I can't imagine what drivers you have that need more than 125W per for fronts. What components do you use and how much power do you think you need for them?

iv yet to buy an amp that leaves me content with the power output 1 week later haha... got 4 cdt es 6.8 golds. they take as much power as I can give them. (redlining the zapco and audison.) I want to give each speaker about 250w +/- ish (depending how well they take it). so 1k to my midbass, and thats not even counting midrange and tweets.

So far I feel like im gonna smoke my amp before my speaker...This feels backwards to me as a daily driver who doesnt wire low.

oh also the midbass are 4ohm coils so that makes this even more difficult to acheive

 

[bump465]

Can you ventilate the area they are in? I mounted in the spare tire area and cut 2 holes for a push pull fan configuration. My box sat directly on the fans but I raised it 3/4 of an inch with mdf strips and it solved my heating issues. This was an old school setup of orion's so they got plenty hot.

well my car has a stock false floor for the spare tire. It seals up very nicely on its own to where no new air can get in. on top of that I also have my box directly on top of the floor. Theres 2 maybe 3 cubes of airspace left so I have my doubts that a 120v fan would sufficently cool them. let alone some 12v computer fan.

 

[hispls 5,000+ posts]

iv yet to buy an amp that leaves me content with the power output 1 week later haha... got 4 cdt es 6.8 golds. they take as much power as I can give them. (redlining the zapco and audison.) I want to give each speaker about 250w +/- ish (depending how well they take it). so 1k to my midbass, and thats not even counting midrange and tweets.So far I feel like im gonna smoke my amp before my speaker...This feels backwards to me as a daily driver who doesnt wire low.

oh also the midbass are 4ohm coils so that makes this even more difficult to acheive

The Brazilians make some HUGE 2 channel full range class D amps. There's a guy local that uses one on a couple doors full of mids and tweets. You'll just need to either buy more than one amp or create your own passive crossover. Best bet these days if you need 1000X2 in class D.

 

[bump465]

The Brazilians make some HUGE 2 channel full range class D amps. There's a guy local that uses one on a couple doors full of mids and tweets. You'll just need to either buy more than one amp or create your own passive crossover. Best bet these days if you need 1000X2 in class D.

im not familiar with many brazilians, taramp is the only one i can think of... that what you mean?

I just considered the 2 channel option when i looked at ct and found their 1600w 2ch for $200, im so tempted - talk about headroom. but its a/b and i fear id have the exact same problem, what class D brazilians?

 

[garychoffmann 10+ year member]

Before you buy new amps. Why don't you buy a cheap digital thermometer that goes up to 150 degrees. Set that in your false floor. Run like normal. Next time they shut off see what the ambient temperature in the false floor is.

Then just rig a piece of wood in there to keep the opening up roughly an inch. So it can exchange some of the ambient air and repeat the process. See if they shut off and the time difference and also the temperature.

The amount of heat exchange needed may not be much at all especially if you keep your cabin below 80 and the spare area exceeds 125-130.

Or buy new amps. That normally fixes everything.

 

[hispls 5,000+ posts]

im not familiar with many brazilians, taramp is the only one i can think of... that what you mean?I just considered the 2 channel option when i looked at ct and found their 1600w 2ch for $200, im so tempted - talk about headroom. but its a/b and i fear id have the exact same problem, what class D brazilians?

Taramps and Stetsom both make big full range 2 channels, not sure about soundigital, but they may. South Americans have a thing for loading up with horns and PA mids so they are a market that would demand some huge power full range amps.

You almost assuredly will have trouble with overheating on any A/B amp especially if you live in the desert and drive more than half an hour at a clip regularly. Really you'll even be putting class D's to the test if you mount them in a spare tire well and push them hard for hours. Still though for 200$ the CT may well be worth the audition. Not like you'll lose a lot if you have to re-sell it.

 

[trumpet 5,000+ posts]

You do not need to give your CDT 6.8s more power. That will eventually destroy them. What I suspect is going on is you want more volume yet you're fighting physics due to low driver sensitivity. What model are your CDT woofers? How are they installed? What are your crossover settings?