LM338 regulated snubberized PSU for audio amplifiers

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Hello all,

Very, very interesting topic. But, I still have a question:

As my transformer only has an output of 22Vac (31Vdc) it is not suitable for me to use regulators in my supply. Therefor I want to set it up as follows:

From the transformer output I want to build 2 separate rectifier/buffer circuits.
- Diodes: MUR860 (as seen a lot here)
- Caps parallel to diodes: 100nF (any suggestions to brand/type?)
- 12000uF per supply rail, followed by 4700uF (both in the supply)
- wires to the chip
- 1000uF with 470uF parallel on the chip.

This would be my supply. Any suggestions?

O yeah, my transformer is a 500VA-type :bigeyes: :bigeyes: for 4 channels LM3875TF.

Best regards,
Mischa
 
Hi,
since you want to build a multi channel amp, I suggest you use dual bridge rectifiers and create the audio ground AFTER the rectifiers.
If you want you can repeat this for each channel. This way every channel has it's own and quiet separate audio ground.
 
Because I wil use the amps for bi-amping, 2 of them will share ground, so they will be put together (once Hi and once Low). Left and right will be separated just as you suggested.

I wil double the large capacity from 12000uF to 24000uF, followed by 4700uF, and each of the 4 amps will get its 1000uF with 470uF parallel on the chip.

Best regards,
Mischa
 
Hey guys, im trying to design diferents PSU for the Gainclone that i build, so i can compare the sound using the diferents PSU.

One of the questions that i have is for example, in the schematic of the LM338 snubberized say that the transformer used are 28-30v but the LM338 datasheet say that the maximun are 35v :S

if i use an transformer with secundaries of 30v, i dont will be using something like 41V?

Thanks in advance.
 
I thought that and tested it with 25vac. Works fine. Looking through the datasheet, unless your using a marginally rated transformer or your mains voltage alters dramatically, you should stay within the dropout limit when a 30v output is required.
 
samsagaz said:
Hey guys, im trying to design diferents PSU for the Gainclone that i build, so i can compare the sound using the diferents PSU.

One of the questions that i have is for example, in the schematic of the LM338 snubberized say that the transformer used are 28-30v but the LM338 datasheet say that the maximun are 35v :S
If you read very carefully, the voltage is _across_ the input and output, not to ground!

96 V in, 61 V out is OK!
 
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