Regulated PS distance from chip

[sunil]

Hello,

I'm designing a regulated PS based on Pedja's schematic.The PS board is in a separate case from the chip. The NS spec sheet says the input caps have to be near the regulators. Thats fine. What about the distance from PS board to the caps near the chip ? Does it have to be close as well ?

Adding the connector cord, the distance from the PS board to the chip-input cap is going to be 75cm (30"). Is this a cause for concern ?

Thanks,
sj

 

[carlosfm]

I'm designing a regulated PS based on Pedja's schematic.The PS board is in a separate case from the chip. The NS spec sheet says the input caps have to be near the regulators. Thats fine. What about the distance from PS board to the caps near the chip ? Does it have to be close as well ?

Use a film cap near the regs, at the input, as the big PS caps are unavoidably a little far.
220~470nf is fine.
On the output of the regs use 47~100nf, again, as close as possible.

On the amp, 100uf caps is fine.

Adding the connector cord, the distance from the PS board to the chip-input cap is going to be 75cm (30"). Is this a cause for concern ?

No.

 

[sunil]

Hi Carlos,

Thanks for that. My setup is a 3-way active. So if this is for the bass, should the tweeter & mid go with the classic unregulated-1000uf design or should these be regulated as well. Especially the tweeter ?

cheers,
sunil

 

[carlosfm]

Hi Carlos,

Thanks for that. My setup is a 3-way active. So if this is for the bass, should the tweeter & mid go with the classic unregulated-1000uf design or should these be regulated as well. Especially the tweeter ?

cheers,
sunil

Sunil,
Are you using separate trafos?
If you have just one big trafo you should regulate everything, otherwise you will have higher (too high?) unregulated voltage on some of the chips.

I'm not a fan of the typical unregulated 1,000uf PSU.
Or regulate, or use unregulated high-capacitance, with snubbers.
If unregulated, I would suggest 10,000uf for the midband and at least 4,700 for treble.

On the chip's PSU pins use 100uf bypassed with 100nf in any case (regulated or unregulated).

 

[sunil]

Hi Carlos,

They are 2 separate trannies. One 225va for the sub & another 1kva with 4 secondaries for the MT's, rear channels & the centre. I know it is not exactly the right way to do things but it was a mistake & I have to live with it. I guess in this case too I have to regulate.

Thanks for all the help.

cheers,
sunil