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Class D Switching Power Amplifiers and Power D/A conversion

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Old 31st August 2009, 12:33 PM   #11
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Quote:
Originally Posted by gexamb View Post
i was looking at the amp7 kit description and it says now they offer it with a PS so that would take care of that.
Really? I think you have a lot more reading and learning to do.

I'm not trying to discourage you, there just seems to be some very basic things you don't seem to understand. Basic things necessary to make a project like this successful.
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Old 31st August 2009, 06:27 PM   #12
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its okay, i dont give up easy especially on things like this. i am very eager to learn. i just need some help getting in the right direction.

i know there are more things involved than the way i posted and made it look like it is more simple than it is.

so i would basically need the kit w/PS, transformer to convert my 13.4V (car battery) source to a higher voltage for the the kit so as to produce more VA for the subs, correct?
and it states that i need another smaller PS for the housekeeping components, i believe one independent 5V rail and another 10V rail. now i am not sure if i can use the stock PS from the kit to achieve this or would i need a small compact independant PS for this.

it is after this point i am not exactly certain what else is needed to make this thing working. I have been searching other threads and post to figure out the basics of it all but its all jumbled. i cant connect the dots so to speak.

if you can guide me in the right direction, i would appreciate it. thank you.
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Old 31st August 2009, 06:59 PM   #13
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The "onboard PS" with the kit is nothing more than a bridge rectifier and smoothing caps. This is meant to be feed by a mains AC transformer. You can't hook up a transformer to a DC power source, they only work with AC.

That is a far cry from being a DC-DC converter capable of boosting the cars DC power supply.

http://en.wikipedia.org/wiki/Switched-mode_power_supply

There is a lot of good info about SMPS for car audio in this thread......

Making car amplifier SMPS with tl494 + DC Protection
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Old 31st August 2009, 07:24 PM   #14
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got it. i was reading up on the chip amp beginners guide and found all that out within 15min. i understand now transformer are for ac ONLY.

so for my situation i would not need a tranny or even a rectifier, just a DC-DC converter (voltage converter). how do i figure out how much output voltage is needed from the converter to get my desired (at least) 2x500w rms channels. because the amp7 kit can handle up to +-70V input.

i will read up on the voltage converter processes, i am sure i will be able to figure that out.

than the converted DC output goes to the chip amp, correct?
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Old 1st September 2009, 06:40 PM   #15
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ok, anonymous you win. maybe i am getting in a little over my head i still dont want to quit on this.

maybe to get some more experience with these amplifier designs, i should try and fix my old amp to see why it is not working. how does that sound?

well here goes:

i have a cadence txa-1000d 1000w @ 1ohm amp (i believe 700w @ 4R).
the problem is that the amp will just not turn on at all. sometimes the green light comes on indicating that the amp is on. sometimes it does not turn on. in any case, there is no power output to the subs. i have not measured anything because my multimeter can only measure up to 10 A so it would fry it basically.

i have posted some pictures of the amp internals, and from what I can see there is nothing burnt, browned, melted, discolored, no broken transistor legs, nothing seems out of the ordinary basically, but then again im no expert. so maybe these pictures can give you a hint as to what is going on.

what things should I look for and how do i go about testing this amp? i know it is hard without a schematic, but i will try and look for one.

thank you.
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Old 1st September 2009, 06:42 PM   #16
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here are the rest of the pictures
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Old 1st September 2009, 07:42 PM   #17
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Quote:
Originally Posted by gexamb View Post
ok, anonymous you win. maybe i am getting in a little over my head i still dont want to quit on this.
Well, that's not what I was after. I was just trying to be the voice of reason, as I've been where you are and wasted a lot of money and destroyed a lot of good components.

You should start a new thread in the car audio forum for your amp. There is a very nice and knowledgeable fellow there named Perry Babbin. If he can't help you fix the amp, no one can.
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