15 A Voltage Regulator with lm338 - Page 2 - diyAudio
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Old 3rd January 2007, 04:27 PM   #11
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Thanks theAnonymous1, Your supply seems good but I don't want to go with discreets at now..

Here is the basic version of the circuit.. Voltage drop along the whole regulator is about 3 volts in this configuration and capable of giving more than 30 Volts according to Pspice simulations...
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Old 3rd January 2007, 09:45 PM   #12
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hi seftali,

If you build this and really want the 15A capacity, remember to size the heatsinks properly.

The minimum case at 15A with a voltage drop of 3V gives 45W. If you use a transformer that requires, say, 6V to be dropped across the regulator then that's 90W.

BTW: A chipamp won't draw 15A for vey long (because it would only draw this much current under fault conditions)

regards
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Old 3rd January 2007, 10:24 PM   #13
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Hi Greg, thanks for the advice.. I will place the amp inside a refrigerator both for cooling and EMI isolation

Is there any thing that is aganist audiophile aproach about this circuit?
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Old 4th January 2007, 03:33 PM   #14
Dxvideo is offline Dxvideo  Turkey
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15A is very big current for me.. But i have a question; how could you find MUR860s in Turkey? Did you purchase them from an on-line store?
PS: I am surprised to find another Turkish member in DIY Audio forums!
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Old 4th January 2007, 04:41 PM   #15
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Quote:
Originally posted by Dxvideo
15A is very big current for me.. But i have a question; how could you find MUR860s in Turkey? Did you purchase them from an on-line store?
PS: I am surprised to find another Turkish member in DIY Audio forums!
Hi, It's very nice to see another Turkish member here It is almost impossible to find specific electronic components in Turkey, I have bought them directly from On Semiconductor web site.. If you are interested, with a couple of friends, we'll buy some components form an online-store to share the shipping cost. You can send a mail..


15A is a big current indeed, but actually It's capable of giving 15A current and It will provide much less current in normal listening. So I don't see any problem in using a high-current supply.
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Old 4th January 2007, 07:51 PM   #16
cjd is offline cjd  United States
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Might want to step beyond MUR860's...
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Old 4th January 2007, 08:14 PM   #17
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Quote:
Originally posted by cjd
Might want to step beyond MUR860's...
I am thinking of some IXYS fast-recovery bridge rectifiers for the future
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Old 5th January 2007, 04:21 PM   #18
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Dxvideo, I have tried to mail you but I think there was a problem with your mail address as I'm always getting the same reply

"Sorry your message to xxxxxxx@yahoo.com cannot be delivered. This account has been disabled or discontinued"
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Old 1st February 2007, 10:00 PM   #19
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Quote:
Originally posted by peranders
[B]Only one LM338 is probably sufficient but min d though that you need to separate windings becuase you'll use two positive regulators.
I made a horrible mistake and bought a 26-0-26 V toroid
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Old 18th July 2014, 11:40 PM   #20
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Hi,
Sorry to re-open the thread 7 years later, did someone tryed this psu ?
I would try to improve it a bit, with my poor knowledge, and lot of feeling.
Why not using 1 op amp for each slave regulator so that there's no more need of output balancing resistor, and raising impedance so much lower ...? It would need to put the same input resistance for each 3 regulator...let say 0,05ohm each. It seem to be a cheap solution with ld1084 instead of lm138 and with ad712 as dual op amp. And supply voltage of the op amp need decoupling, and so should be taken before the resistors...
LM138 allow by itself 12A transient, so x3 =36A, wich could be a lot too much. Ld1084 is a ldo, and is current limited at 7A so 21A for 3.
And a common mode cheap inductor after rectifier should help reducing diode switching hamonics (cheap => high resistance=> protect from high current demand from capacitor bank).
To me this design seems simple and cheap, adding power and thermal protection for high power.
Does what i'm talking about make sense ?

Thanks,

Damien
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