Chip amp power supply- a beginners guide - Page 4

pirej · 12th November 2008, 03:16 PM

Need help:

I have transformer 32-0-32 ..5 Amperes... and wanted to use to "drive" my Gainclone, made by LM3886 (stereo version).

- If I use 40v capacitors can I get "normal" power supply for GC?(for example 36-37v per rail).

-Is there a schematics for regulated supply in which my transformer will fit? (Lt1083 or somethnig else..) to lower the supply on 35V per rail..

- No way - just to make single supply version (to use as 64V or twice by 32V?)

- Or...

Redshift187 · 12th November 2008, 08:04 PM

Your transformer puts out 32V AC. Multiply by 1.4 and you get 44.8V DC. The maximum for the LM3886 is 42V. Also, using a 40V capacitor with 44.8V rails will cause destruction of the capacitor. The capacitor is not a limiter, it must be rated for higher than the highest voltage it will see.

A regulated supply is your best bet if you want to use that transformer. Unfortunately I can't help with that.

Peter Daniel · 12th November 2008, 08:18 PM

Quote:

Originally posted by pirej
-Is there a schematics for regulated supply in which my transformer will fit? (Lt1083 or somethnig else..) to lower the supply on 35V per rail..

Check this thread: LM338 regulated snubberized PSU for audio amplifiers

pirej · 13th November 2008, 07:30 AM

Thnx for the response,
Last question -
The trafo that I have, has only three wires as secondary 32-0-32, which means - NO independent secondaries.

can I use Carlos regulated PSU as shown in attachment?

AndrewT · 13th November 2008, 08:42 AM

No.

pirej · 13th November 2008, 11:51 AM

The last try by me to use the trafo

Is this OK?

pirej · 13th November 2008, 12:07 PM

The last try by me to use the trafo

Is this OK?

AndrewT · 13th November 2008, 12:37 PM

Hi,
are you trying to get+-24Vdc from your regulators?
Then use a 24Vac or 25Vac transformer.
You need a single bridge rectifier if you use a centre tapped transformer.
You can use either a dual or a single bridge rectifier if you use a dual secondary transformer.

pirej · 13th November 2008, 02:33 PM

I'm trying to get 35v regulated as max. for stereo LM 3886.

The above schematic is OK with my trafo 32-0-32v?

j.wright · 13th November 2008, 02:51 PM

I would love to build a chip amp based amplifier for my automobile... Any chance of some advise on designing a Power supply for Automobile enviroment ?

13th November 2008, 08:42 AM	#35
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	No. __________________ regards Andrew T.

13th November 2008, 12:37 PM	#38
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, are you trying to get+-24Vdc from your regulators? Then use a 24Vac or 25Vac transformer. You need a single bridge rectifier if you use a centre tapped transformer. You can use either a dual or a single bridge rectifier if you use a dual secondary transformer. __________________ regards Andrew T.

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12th November 2008, 03:16 PM	#31
pirej diyAudio Member Join Date: Sep 2007	Need help: I have transformer 32-0-32 ..5 Amperes... and wanted to use to "drive" my Gainclone, made by LM3886 (stereo version). - If I use 40v capacitors can I get "normal" power supply for GC?(for example 36-37v per rail). -Is there a schematics for regulated supply in which my transformer will fit? (Lt1083 or somethnig else..) to lower the supply on 35V per rail.. - No way - just to make single supply version (to use as 64V or twice by 32V?) - Or...

12th November 2008, 08:04 PM	#32
Redshift187 diyAudio Member Join Date: Aug 2008	Your transformer puts out 32V AC. Multiply by 1.4 and you get 44.8V DC. The maximum for the LM3886 is 42V. Also, using a 40V capacitor with 44.8V rails will cause destruction of the capacitor. The capacitor is not a limiter, it must be rated for higher than the highest voltage it will see. A regulated supply is your best bet if you want to use that transformer. Unfortunately I can't help with that.

13th November 2008, 02:33 PM	#39
pirej diyAudio Member Join Date: Sep 2007	I'm trying to get 35v regulated as max. for stereo LM 3886. The above schematic is OK with my trafo 32-0-32v?

13th November 2008, 02:51 PM	#40
j.wright diyAudio Member Join Date: Apr 2008	I would love to build a chip amp based amplifier for my automobile... Any chance of some advise on designing a Power supply for Automobile enviroment ?

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