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audio3 2nd August 2012 03:31 PM

Hiraga power supply
Hello. I have a problem, anyone help me thank him. I'm building a Hiraga 20w (DIYAUDIOWORLD PCB) with salvage parts, I have a voltage of 27,5V , how can I do to bring it to 21V ?

ChicagoJTW 2nd August 2012 04:30 PM

There are a couple of ways to accomplish this. The simplest would be to insert a power resistor in series with your power supply (one on each side, plus and minus). You might try something around 7-10 ohms initially. The power resistors should be rated for at least 25 watts and should be heat-sinked.

audio3 2nd August 2012 05:37 PM

Thanks, the other way?

ChicagoJTW 2nd August 2012 07:13 PM

You can use a regulated supply, though Hiraga generally does not recommend them for his Le Monstre or 20W amp.

Still another means of dropping voltage is to use a bunch of diodes in series. As with the resistors, they will need to be heatsinked.

StigErik 2nd August 2012 07:32 PM

It's no big problem running the 20W LeClasse A on 27,5V. In fact the original production version of the amp had 24V supplies, not 21V. At least the one I owned did.

Be aware that the PSRR of the LeClasse A is very low, so the PSU needs to be very stable and clean.

audio3 3rd August 2012 11:11 AM

Hello. Thanks guys for the answers!
Then I can feed it to 27.5 V, I make some changes to the values ​​of the resistors on the PCB?

juma 4th August 2012 03:50 PM

I do it with capacitance multiplier, like this:
Rails' voltages will be about 4V lower, the ripple voltage will be decreased by about 50dB and, most important, your amp will sound better.

audio3 7th August 2012 06:51 AM

Thanks, I'll try these solutions.

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