Power Supply for Hiraga

In a French audio site there is a discussion going about the power supply for the 30 watt Hiraga. There are several members who did compare all kind of power supplies. And they all; agree that the one giving the best results was an CLC supply.
I would use all the 52000µF after the choke and get an extra 22000µF to use as an input cap after the rectifier.
Depending on the current you coulduse a Lundahl LL1694 or LL2733 with with the 2 colis in parallel.
Greetings, Eduard
p.s if pos and neg current are identical you could use a single choke and use it in what Lundahl calls coomon mode
I need to build a power supply for a 15W Hiraga Le Monstre clone (Jims Audio), I have 4 x 52000uf capacitors and a transformer, what else do I need or are there any suitable boards I can buy?

Mr Hiraga don't do 15 watts solid state amplifier
He presented 8 watts who was called " Le Monstre " with battery power supply .

Jims Audio amplifiers use probably other schematic.....are not original Mr Hiraga class A topology amplifiers.

The Class-A Amplifier Site - Hiraga 'The Monster'

Best regards :)


Paid Member
2008-10-18 11:31 am
I designed this supply for my 20W and am happy with it. As always, layout is a factor.


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@eduard can you please suggest approximate value of choke to be used in CLC for 30W Hiraga?

i'm planning to use 1/2 Farad of caps after rectifier. power transformer value would be 400VA for a mono channel.

In the EIGHTIES i did build a 30 watt Hiraga with componants which i did get in the famous shop in Paris. At that time they also did have the single ended Nemesis transistor amp designed by Jean Hiraga which did use a 200 mH 1 ohm 1,5A . Because i work in a company which manufactures steel products it was not a big problem to change the CRC filter into a CLC filter so i did ask them if that would be a good idea. THey said sure so i did!
I wouldnt make the first cap to big because it would be stressfull for the power transformer and the rectifier.
A few months ago i did ask Lundahl if it would ber possible to use the LL2733 or the LL1694 in what Lundahl calls a common mode for an amp like an Hiraga. They said sure if the currents going through both coils is the same.
Both Lundahls have their current rating specified for an AC voltage much higher than the voltage that will be present in a Hiraga CLC filter so they will be able to handle more current.
I dont know if i would go for the LL1694 or the LL2733. I think i would try choke input but then you will need another transformer .
Greetings, Eduard
P.s both Lundahls can also be used for choke input


Paid Member
2008-10-18 11:31 am
It is possible to use any transformer as choke.
Power transformers can be good value for choke input but for a second stage, or for CLC you may sometimes want more of an air gap, you might get away with a smaller value air core or just a very large core (not necessarily toroidal though).

I have a pair of these (95mH, 200mOhms) that I can't saturate in any position or current used with my SS amps.

These are the ones I am using with the above supply. It was previously choke input using these, and I had air cores as a second stage but I went to CLC to get the rail voltage up using the same power transformer and now I don't need the extra stage.


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For my soon to be finished DDDAC i am using Lundahl chokes. Current for the total circuit is around 900mA because there are some shunts. No problem at all with heating or noise because of high current.
End of this year i will take some LL2733 400mH 1,7A to a friend in Vietnam who will use it for a single ended transisitor design by Nelson Pass.( Sit nemesis)
So far people building Pass amps are using air coils or low below ( 10mH) Hammond iron core chokes while Lundahls are available
Give them a try!
In my dac i am using the LL2733 connected in common mode because i dont think the dcr is a big issue. It could be an isssue when used for a power amp?
If i had to choose i would use the LL1694 in common mode or the LL2733 with coils in parallel.
AND i would go for choke input but of course you can try CLC first. With choke input there are some issues like a minimum current you need to make it work.
Greeetings, Eduard
@eduard, sorry for the confusion. What I meant was 1/2 Farad of capacitance in total and not before L in CLC. I'm planning to split it 1:4 .

@cumbb , I'm planning for 2 mono channel builds in separate chassis. So for choke can I use a small toroidal transformer!? Or,
Can I use inductors meant for crossovers!? Like in the following link,
16 AWG Steel Laminate Inductors OFC
The stereo amp i build did use 2*68000µF and 4*330000µF for the complete power supply.
The original design did use use a small less than 300VA double c core but because it was out of stock i did return from Paris with a 500VA EI core that was used in another design lol. Recently i did read that the smaller transformer would also function as a kind of soft start up because these caps were considered really big at that time. Most of the money went into the power supply!
Making the first cap big is not so good. It will give the transformer and the rectifier a hard life and you will create all kind of switching noises that are hard to filter.
These crossover parts can be used but they are not the real thing. I think a 10 mH will not filter that much and i think the lundahls are constructed in such a way that they will interfere less with surrounding parts and a LL1694 will provide a nice soft start up as well.The group of people close to Hiraga did use 200mH chokes when they did use chokes.
I did use a lot of Lundahls chokes and they always did work perfectly.
A chance while using a trafo is, to shorting a winding to cut the impedance - to compare L/R and R, and to tuning by switching. L/R does not sound everytime very well. It seems a little bit "tough" often.
I would use a bigger one, for your pp-Hiraga (ca. 2 x 20 V, 2 x 1 A per channel?) 150 VA-trafo. Just try.
If mono-psus, make sure a connection between. At the last step. Positive - positive, negative - negative.
My mind.
thanks @cumbb

i've a query regarding the toroidal transformer. i'm planning to use 400VA trafo with 20V secondary for the power supply. but i also need power supply for speaker protection module - the one i'm looking for needs around 24V AC input. what should be the VA value of trafo to accommodate this 24V AC [dual secondary] - i don't want to 'disturb' power supply for amp circuit. or is it better to use a separate trafo for speaker protection module?
today i was playing around wit PSUD2 to simulate how would my new hand wound air core inductors would fair in a CLC filter against CRC.

the air core inductors are made with 13 AWG wire, around 1.5 inch of diameter and 1 inch length - around 80 turns. each of these weigh 500 grams have a resistance of 0.1 ohms. on calculating the inductance turns out to be measly somewhere around 350uH [micro Henries].

simulation on PSUD2 is far from encouraging. i was under the impression that if not indcutance, atleast resistance [0.1 ohm] in the coil would act as CRC.

CLC simulation:

CRC [R at 0.25 ohms]:

interestingly if i run the simulation for CRC with 0.1 ohms resistance, the output graph is very close to above CRC.
this is the first time i'm using PSUD2 and not sure if i've set parameters correctly. to look at it has simple UI.

so low value inductor is bad in filtering even with inherent coil resistance?
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