Hiraga "Le Monstre"

[Nikos]

Finally setup for 4Ω version
+/- 22-24V
330pf input cap
Bypass resistor 68k
On 1k res cold 1.20V -1.34V
0.47Ω resistor bias 730 -750mv about 1.6A
220 -20Ω gain resistor
Offset +/- 2 mV
Trimmer 53-48 Ω
2sj74Gr -2sk170gr 3.0ma idss
Cascode 1845-992
Drivers 4793-1837
Output 1987-5359
1khz 10khz 40khz. Square wave 1khz sine wave before clip.

 

[EUVL]

You are running the output devices at 40W each.
With 3.2A output current in Class A, output voltage across 4R is only 13V.
Unless of course you also want to use it for 8R.


Good luck,
Patrick

 

[Nikos]

Thanks Patrick for your wishes and your comments
We'll see how it sounds in practice. 8R And 4R
Good luck to you too.😉
Nikos

 

[Nikos]

Test with load 2 X 6.8Ω parallel.
What made a big impression on me is the square wave at full swing It remains rock steady until clip.I can't wait to hear it, this little Μonster seems to have a lot of promise.

 

[Nikos]

Today I used the power supply Class A cap multiplier from the Alpha Nirvana 39 amplifier. All the more stable since the batteries are small and do not maintain their voltage for long .
Same measurements....
Voltage 22V +/-
Bias 712mV on 0.47Ω
Offset 1.5mV +/-

 

[Nikos]

Even with cheap materials, that is, resistors, the amplifier is very stable, i have two pairs of boards left.
If anyone is interested, please send me a Pm .
Dimensions pcbs 5cm x 5.5cm.

 

[m0rten]

Hello

These speakers I used with the Le Mosntre . The enclosure about 12L BR..
I use Visaton AL130 and Audax tweeters .
I was satisfied with the Le Monstre , and my speaker only 87db.
I had more than enough bass , with the P Daniel Gain clone the bass was a bit shy.
Right now mostly I build my amp using power mosfets..
But also I want to give a try the Hiraga Class A one more time , to me that has more balanced sound.
Has more tube like sound..
These is a new type of PC board , not finished yet. Power transistors etc need to be mounted.

Greetings

Hi Gaborbela!
I am looking through this long thread (again), and I notice this PCB. Did you ever finish this project? Did it work, and if yes, how?

 

[Nikos]

Output transistors for Hiraga.....
Has anyone used them? I would like your opinion.
It is original?

 

[grunf]

I have a feeling that these are copies, I don't remember ever seeing such 2SD1047/2SB817. There were other manufacturers besides Sanyo, but they still look different from Sanyo. Otherwise, if I knew they were original, I would try them at Le Monstre.

 

[Nikos]

Im ready for a box.....new boards Hiraga Le Monstre 4Ω version +/- 22V Bias 1.4-1.5 A, offset +/- 1-2 mv thermal couple Jfet and Cascode transistor.
The amp its rock steady.

 

[Nikos]

Progress....

 

[Nikos]

Ready the Hiraga Le Monstre module, in place of AN39 module.

 

[Nikos]

Well done.... excellent behaviour inside the box 1-2 mv offset 740 mv on 0.5Ω resistor about 1.45A bias.
22.5V +/-
Its time for listening.....

 

[Gill.T]

@Nikos, Rest of the system remains same?
Would be interesting to know how it compares to AN39.

 

[potepuh]

Interesting front plate

 

[Nikos]

@Nikos, Rest of the system remains same?
Would be interesting to know how it compares to AN39

Yessss the same exactly.
I will inform you my friend.

 

[Nikos]

Interesting front plate

It is made of two pieces of laminated oak flooring glued together.
Which together reach a thickness of 1.4 centimeter.
It will be cut to the appropriate dimensions tomorrow.

 

[Nikos]

From the short time I listened to it without reaching maximum bias 1.5A , my first impressions are very good ....very great clarity, large soundstage and not particularly excessive bass...No noise at all , hum or hiss.
In relation to ΑΝ39 I have the impression that Hiraga It has a sharper bass while the An39 has a more extended bass.
Impressed!!

 

[Remnant Parts]

Output transistors for Hiraga.....
Has anyone used them? I would like your opinion.
It is original?

It is not original. I use this original with 1 A bias with good result. I found this picture in Rotel amp RA-02 issue in this forum.

BR,

Josh

 

[Nikos]

Front plate Done....