DIY AC to DC Power Supply for DIY Class D Amp - AVS Forum
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post #1 of 11 Old 05-07-2012, 10:42 AM - Thread Starter
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For some time I have been very interested in the DIY Class D amp boards from Sure. They normally are pretty reasonable with respect to price. I wanted to possibly DIY a power supply as the power supplies that were available seemed a bit on the weak side, especially if you were to run more than one amp off the same power supply with any output wattage close to 100W.

Are there reasons why more folks don't do this?
I am a novice/intermediate and understand the basic concepts at play here. I would like to get some advice on this design and see if its economical to build.


I already planned to build a "felix" EMF/RFI filter so I have all the parts for that covered. I plan to put the felix in front of the power supply as a filter.
What I would like advice on are the Bridge rectifier and the Capacitance for C4. I assume a series bank of capacitors will work here(C4) to satisfy requirement to reduce ripple? Any idea what total capacitance would be enough for a 24-50V output? Are there more details needed? I know overkill here is ok, I just don't want to undershoot.


Can Anyone recommend a Bridge rectifier which would work? What goes into choosing one?


Here is my diagram, please critique and suggest whatever I want to learn.


LL
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post #2 of 11 Old 05-07-2012, 11:00 AM
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Just buy what you need

https://www.hypexshop.com/shop/shop.jsp?groupID=117
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post #3 of 11 Old 05-07-2012, 11:21 AM
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Any modulation of the power supply modulates the output of the amp, thus the very high-end class D designs use regulated supplies. Making a regulated supply for a power amp is challenging. I agree, just buy one. If it is not regulated, put as much wideband decoupling (capacitors) as you can get on the output.

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post #4 of 11 Old 05-07-2012, 12:35 PM
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post #5 of 11 Old 05-08-2012, 04:47 PM
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Using a bridge rectifier on a Class D amp is a big no-no.
Only old-school Class A/B and H type amps use those types of circuits anymore.

High-end Class D amps that are +70% efficient use universal SMPS's with PFC (or equivalently esoteric solutions).

You will not see >50-70% by using a conventional bridge rectifier circuit.
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post #6 of 11 Old 05-08-2012, 05:18 PM
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Quote:
Originally Posted by BassThatHz View Post

Using a bridge rectifier on a Class D amp is a big no-no.
Only old-school Class A/B and H type amps use those types of circuits anymore.

High-end Class D amps that are +70% efficient use universal SMPS's with PFC (or equivalently esoteric solutions).

You will not see >50-70% by using a conventional bridge rectifier circuit.

do u know why amps these days only last a few years where is amps from 20 years ago are still going b/c those old power supplys are made to last unlike smps which will fail at some point. having a power supply that is 70% efficient isnt as bad as it seems when matched with a class d amp that is 90%. good amps dont use smps. the idea that smps are ever going to be superior is ridiculous. stick with the crc power supply.

what amp are u trying to use it with i could easily find a good ps for it.


heres a pic of my 8 channel amp that cost me a little over $500

wattage rms @56v
200/8ohm
400/4ohm

http://img407.imageshack.us/img407/3242/img9064p.jpg
http://img16.imageshack.us/img16/7775/img9063pl.jpg

using 500va formers from antek i replaced all the caps.

http://www.ebay.com/itm/Power-supply...item2c639b5a6b


http://www.ebay.com/itm/L15D-Digital...item1c198413d6

dont use sure boards they are pretty horrible as many have had problems with them,these measure amazingly for the price but they do need speaker protection boards also.
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post #7 of 11 Old 05-08-2012, 06:38 PM - Thread Starter
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I got turned onto these guys on another forum, seems cheap and the amps seem pretty nice too.....

http://connexelectronic.com/product_...usqc8acbovkjb5
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post #8 of 11 Old 05-08-2012, 07:23 PM
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Quote:
Originally Posted by NicksHitachi View Post

I got turned onto these guys on another forum, seems cheap and the amps seem pretty nice too.....

http://connexelectronic.com/product_...usqc8acbovkjb5

dont i got a smps that is dead from him after a few months of use.
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post #9 of 11 Old 05-08-2012, 10:18 PM
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Quote:
Originally Posted by cookieattk View Post

heres a pic of my 8 channel amp that cost me a little over $500

wattage rms @56v
200/8ohm
400/4ohm

http://img407.imageshack.us/img407/3242/img9064p.jpg
http://img16.imageshack.us/img16/7775/img9063pl.jpg

That's a pretty cool project. Do you have a build thread anywhere?

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post #10 of 11 Old 05-08-2012, 10:28 PM
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Quote:
Originally Posted by cookieattk View Post

do u know why amps these days only last a few years where is amps from 20 years ago are still going b/c those old power supplys are made to last unlike smps which will fail at some point. having a power supply that is 70% efficient isnt as bad as it seems when matched with a class d amp that is 90%. good amps dont use smps. the idea that smps are ever going to be superior is ridiculous. stick with the crc power supply.

Explain how I reached this number then?


I've been running 6 SMPS's for 7 years, with no failures.

Even if my IT8000 failed, they will put in a new one for almost nothing.

I waste more money on gasoline each month than the total sum of all SMPS failures repair costs I have experienced.

Compare 200lbs of Powersoft K20 amplifiers to 200lbs of bridge rectifier style amplifiers and see which plays loudest.

The internet runs on millions of SMPS's to power everything from CPU'S to routers and firewalls and UPS's to killawatt NVidia GTX 690 graphics cards.

Every touring band and supercomputer and data center (like google) uses zillions of SMPS to power their gigawatts of stuff.

SMPS are superior for everything except arc-welding sinewaves into water cooled resistors.

They are here to stay and will only get better with nanotechnology.
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post #11 of 11 Old 05-08-2012, 10:59 PM
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Quote:
Originally Posted by BassThatHz View Post

Explain how I reached this number then?


I've been running 6 SMPS's for 7 years, with no failures.

Even if my IT8000 failed, they will put in a new one for almost nothing.

I waste more money on gasoline each month than the total sum of all SMPS failures repair costs I have experienced.

Compare 200lbs of Powersoft K20 amplifiers to 200lbs of bridge rectifier style amplifiers and see which plays loudest.

The internet runs on millions of SMPS's to power everything from CPU'S to routers and firewalls and UPS's to killawatt NVidia GTX 690 graphics cards.

Every touring band and supercomputer and data center (like google) uses zillions of SMPS to power their gigawatts of stuff.

SMPS are superior for everything except arc-welding sinewaves into water cooled resistors.

They are here to stay and will only get better with nanotechnology.

sigh i was speaking in relevance to what is in his budget... the smps in the $80 range are all trash where is a liner supply is not. unless he wants to spend $200 on a smps that a $70 liner supply inc transformer can do. ALSO when the economy tanks and Apocalypse is upon us the heavy copper transformers can be made into a weapon.
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