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-   -   15 A Voltage Regulator with lm338 (http://www.diyaudio.com/forums/chip-amps/93342-15-voltage-regulator-lm338.html)

seftali 3rd January 2007 12:50 AM

15 A Voltage Regulator with lm338
 
Hi, I wonder why nobody has not talk about this configuration taken from LM338 datasheet...
http://img101.imageshack.us/img101/838/lm338mo2.jpg

LM307 is discounted but I think LF411 can be used instead...

Any ideas about this regulator? 15 A on each rail seem quite enough for a gainclone:D

DcibeL 3rd January 2007 07:21 AM

Hmm... 6 LM338 ICs (3 per rail) would take up a lot of PCB space when considering the size of some PCBs made for the LM3886, and I'm sure they'll require heatsinking of some sort. Would make for a fun experiment to try out. Are you planning to construct this regulator ans try it on an amp?

I hate that word....Gainclone...I especially hate it when the word is used to describe something that shares no similarity to the Gaincard except that it uses the same amp IC.

peranders 3rd January 2007 08:17 AM

Only one LM338 is probably sufficient but min d though that you need to separate windings becuase you'll use two positive regulators.

Check digi01's design.

seftali 3rd January 2007 09:50 AM

Quote:

Originally posted by DcibeL
Hmm... 6 LM338 ICs (3 per rail) would take up a lot of PCB space when considering the size of some PCBs made for the LM3886, and I'm sure they'll require heatsinking of some sort. Would make for a fun experiment to try out. Are you planning to construct this regulator ans try it on an amp?

I hate that word....Gainclone...I especially hate it when the word is used to describe something that shares no similarity to the Gaincard except that it uses the same amp IC.

Completely right;) I apologise for using the word "Gainclone", I should have used "ChipAmp" :)

Yes, I am planning to build this regulator as it is relatively simple than any other high current regulators. I am thinking bi-amping but I still don't sure about which chipamp to build:confused: Maybe Mauro's my_ref C..

seftali 3rd January 2007 10:02 AM

Quote:

Originally posted by peranders
Only one LM338 is probably sufficient but min d though that you need to separate windings becuase you'll use two positive regulators.

Check digi01's design.

I know, It will look like the regulated power supply of Carlosfm ; I will just replace the single lm388 with the circuit above...

I don't want the power supply to limit the sound that's why I looking for something more powerful than single lm338:)



MaxS 3rd January 2007 10:26 AM

Hello,

You'll have a look at LT 1083 ( 7,5 A ), it would be a good thing.

AndrewT 3rd January 2007 10:30 AM

Hi,
why are you considering regulation and chipamp?
That seems to defy the simplicity that chipamp brings.

Plain, ordinary rectifier/smoothing caps suffice.

Or, go brute force and fit VA=2*power output & smoothing @ +-20mF/channel

seftali 3rd January 2007 10:46 AM

Quote:

Originally posted by MaxS
Hello,

You'll have a look at LT 1083 ( 7,5 A ), it would be a good thing.

Thanks, I will consider them for future projects however I already have some lm338s in my hand.

Quote:

Originally posted by AndrewT
Hi,
why are you considering regulation and chipamp?
That seems to defy the simplicity that chipamp brings.

Plain, ordinary rectifier/smoothing caps suffice.

Or, go brute force and fit VA=2*power output & smoothing @ +-20mF/channel

I came across with chipamps a couple of months ago. Since then I was searching nihgt and day:o At first, I decided to built an unregulated one but then I red that the regulated is much better and I decide to build a regulated one... Somes says switching is even better than regulated one but I don't like switching psu.

Actually, I am not interested in simplicity much. My real goal is the sound quality. I have give up from buying a Creek Destiny amp. after coming across with chipamps. Therefore I want to make a chipamp which should sound at least as Creek Destiny does.

seftali 3rd January 2007 11:49 AM

By the way, Supply voltage range for LF411A is +/-22 V and diffrential input voltage range is +/-38 V.

So I think 35 V for Vin will not cause any trouble and I guess Vout will be something around 30 V.

theAnonymous1 3rd January 2007 02:41 PM

Another option is a pass transistor regulator like the type discussed here

I'm not sure how it compares in the audiophile world, but in my world it turned out to work very well.

Right now I'm using one 2n3055 per rail. I guess I could have just used a single LM388 per rail, but this was a lot more fun and I learned a few things in the process.

Pics of the supply powering a class-d amp at +-35v......

http://i11.tinypic.com/2exshz8.jpg
http://i11.tinypic.com/2hdmflg.jpg


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