Hiraga "Le Monstre"

Thank you. Any other suggestions? And what about sound comparisson with Apex A14?

Well, some say the BC546 and BC556, and the BD139 and BD140 works just fine, but i am not sure. I can't compare it to the A14, but i can compare it to the JLH 10W, the TDA2050, the TDA7294, the STK-056. For me, this amp is better than all of these, because it produces a very natural sound. When you listen to it, it feels like a plug was removed from your ears. This is the best description i can give.
 
original parts

Are you sure these are the original parts of the Monstre? Hiraga was very fuzzy about parts and did a lot of testing and hearing (as stated in the articles at the time).
- cosmos pot from japan (very expensive, like €20 for 1 pot, yours seems to be Bourns?).
- white cement power resistor on pcb, don't know make (yours is green).
- caps on pcb were tantalum
- no toriodal transformer but some block-formed one.
- 1 Farad of buffer of brand so and so
- special brand of cable for inside wiring

etc etc it's all in the original articles.

I don't say you have to use the same components as Hiraga, it is virtually impossible these days.

BTW I have built tens of Monstres during my life. Some completely original and most with variations. It seems to matter but you have to try for yourself what suits you (not being happy too soon). For me the 20Watter was easier to build to the same standards with other components, this one seems to be more forgiving in character soundwise.


For the Monstre he used the same parts as used for 20Watt version:

I build the Hiraga 8W class A amplifier some 30 years ago using the original parts. At that time the power transistors I received were already surface viped to hide the part numbers!
It still sounds really good having more than enough power for normal listening. I even used it at parties together with some home made JBL based PA speakers.
A few more pictures from the project are found on this Norwegian forum.

PCB close-up:

View attachment 639716

Simple solutions also work! PCB was made with ink pen... :)

View attachment 639715

Amplifier chassis using an old main frame power supply:

View attachment 639714

Party speakers:

View attachment 639718
 
le class
 

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First Build of the le monstre, power supply ideas?

Hi to all my DIY Hiraga family out there! I decided to build this amplifier as it is popular and there are many kits available, plus it's not too expensive to build.

Please see attached schematics.

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So far i have bought 16x25v@47000uf capacitors, i also have two toroidal transformers 160va 2x12v 6.67A.

I have a few questions about the power capabilities of this amplifier, now i know it runs at 12V and i know that probably after rectification and going thought the capacitors the voltage will increase, so what i want to know is . will this be ok? Can these amp boards take the high voltage? If not what would you suggest i change in terms of components to handle the extra voltages? Or will it be ok?

I'm not fussed if it's 8w or 15w, i just want to learn how to set it all up i.e the bias and to get it sounding as good as i can with what i have.

Would i need a soft start and speaker protection modules? I will be building the chassis and heatsinks myself!

Any tips would be greatly appreciated.

Thanks

V
 
Hi to all my DIY Hiraga family out there! I decided to build this amplifier as it is popular and there are many kits available, plus it's not too expensive to build.

Please see attached schematics.

View attachment 664201


V

If I were to build this famous amp my Aquarius ascendant would force me to introduce some mods:

1) Choose higher power rails, anything from +/- 15VDC to +/-24VDC.

2) Use Power Regulator (in my case the PowerReg from Teddy Pardo) to save money on power caps. Of course, I would also use my other PS secret weapon: the "charge-transfer supply" from -ECdesigns-

Introducing the PowerReg | pink fish media

3) Cascode also the outputs with BJT. Given the higher power rails, no loss on headroom.

4) For the ultimate sound quality: do a cascoded common-source VFET output, but that would need another higher power rail for the bias.

At the moment I am totally busy with multiple projects but this one is in my "to do" list.
Best of lucks.
M.
 

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Here is my built. Enclosure work done by me. All PCB's purchased as a kit.
An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.


Here is the link of my drive folder in which i have stored all the built photos, might help someone to get ideas to built an enclosure.

Le Monstre - Google Drive

Sadik