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masag 20th May 2006 09:46 AM

Hiraga MC + Pass PSU
2 Attachment(s)
Dear Sirs,

I've found these schematic in the forum, and want to start with it.

Does anybody can give me some information?

I want to substitude the MAT's with matched 2SA1316 and 2SC3329

the jfets are matched 2SK170's.

What do you think about?

For the PSU I want to use the Pearl-PSU, but I would need help to calculate it down to 12 V. Maybe I can get some advice from this great forum?

Thank you


masag 20th May 2006 09:51 AM

2 Attachment(s)
Here the Pearl PSU

hacknet 21st May 2006 04:54 AM

imo, if you want to build a nice fancy power supply, you should try the jung regs. apparently they sound really good on noise sensitive equipment like phono amps.

masag 21st May 2006 06:01 AM

Super regulators
Thank you,

but I believe that a simple circuit needs a simple psu.

Nobody here that can help me calculating the pearl psu down to 12V?


hacknet 21st May 2006 06:04 AM

you have to change the voltage divider ratios R10 and R11 with reference to the zener D1.

masag 21st May 2006 06:23 AM

Can you give me a formula how the the the voltage devider should be calculated?


forr 21st May 2006 10:37 AM

2 Attachment(s)
The design you show is not due to Jean Hiraga but to Serge Rabeyrolles. The starting idea was the so called Hiraga's circuit which was a simple common base circuit biased like a current mirror. Here it is. The Rabyerolles's circuit has some negative feedback which makes it having a little more input impedance than the Hiraga's.

masag 21st May 2006 11:08 AM

thank you for taking a look at my thread.

Now I found the original print at Bonavoltas. You are right Forr!

Did you ever listened to Serge Rabeyrolles version of the prepre?

Yesterday I finished my TD160 an plugged it to my Rotel 970 Phono-preamp (my only non-modified part in my audio chain, sound not really good)), and made immediately the decission to start up a new project.

A friend of mine has built a wonderful Hiraga Pre-Pre battery powered, but why not start a new project?



Onvinyl 26th April 2008 10:16 AM

Right at the moment, I'm experimenting with a version of the circuit of the first posting. Im using 2sk389 for the current sources and THAT-corporation 340er transistor die for the current mirrors. And trying 2sc1775/2sa872, zvn3306/zvp3306 and 2sk982/2sj148 as the bipolar driven folded cascodes, all with decent results. Hard to say which sounds really better.

I use a bit different resistor values and no NFB. I'm experimenting with a servo, because the DC wanders a bit, but with no luck so far.

If I cap-couple it, it sounds very nice: both relaxed, serious and very detailed. (with passive riaa and pass/curl/hansen -style open loop second stage).


c.d.s. 31st May 2008 03:58 PM

hiraga le pre pre

Im interested to know what results have been had with a 12v source from a PSU as
opposed to battery power, has anyone done a comparison?



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