There are quite a few errors on that PCB, nice idea - although needs tweaking.
The 2k resistors nearest to the front end will need to be adjusted many times to get the amp to work (THD/ bias etc), you would be much better allowing them to be through hole. The caps don't need to be 1500uF, 47uF Black Gate F's are the best that I've tried. Stick with the intended JFET front end. Not sure all those tiny bypass caps are needed either, likely they will cause ringing and no give you the result that you imagine.
The original designer was a genius, you'll not manage better
The 2k resistors nearest to the front end will need to be adjusted many times to get the amp to work (THD/ bias etc), you would be much better allowing them to be through hole. The caps don't need to be 1500uF, 47uF Black Gate F's are the best that I've tried. Stick with the intended JFET front end. Not sure all those tiny bypass caps are needed either, likely they will cause ringing and no give you the result that you imagine.
The original designer was a genius, you'll not manage better
I have the original 30w with the original pcbs and components and I confirm that it is an excellent amp, in any case, one of what I keep.
Greetings to all over there, I am going to build Le Monstre 8 watts, I have already asked for blue boards in HiFiStor in your experience which line preamplifier do you recommend, I take the soldering iron again the last project before the damn pandemic was a 1969 JLH . Thank you very much
https://www.diyaudio.com/community/threads/jlh-10-watt-class-a-amplifier.3075/page-474
https://www.diyaudio.com/community/threads/jlh-10-watt-class-a-amplifier.3075/page-474
Greetings again, I already ordered the following components
Thanks in advance for your advice.
Hiraga "Le Monstre" 8W A class Amplifier blue board
Hiraga A Class Power Supply PCB D.I.Y
VISHAY 256 47000uF 16v Power Miniaturized HQ CAPS FOR AUDIO HIRAGA AMP
LM338 Linear Regulated Power Supply Board 15A DC-DC Converter Board
I already have the chassis with heatsinks, it is small, which is why the psu will go in an old chassis of a sff dell 3040 pc, also have the 250 watt toroidal transformer (45-0-45-15v-0-15v).Thanks in advance for your advice.
Jean Hiraga's Le Monstre / Monster - Class-A 8W DIY Amplifier Project using a regulated power supply.
http://diyaudioprojects.com/Solid/Jean-Hiraga-Le-Monstre/
Attachments
Hello,
Best sound clc with LL2771 lundahl choke with both coils in parallel and possibly adjusted airgap to get maximum inductance at desired current rating.
My friend uses this in his Hiraga amp . I think he asked Lundahl to make it suitable for 2,75 A with coils in parallel. The standard one is 750 mH 2A .
Making it choke input could be even better but you must take care of the minimum current to make it work as a choke input all the time even with no amp connected.
Greetings Eduard
Best sound clc with LL2771 lundahl choke with both coils in parallel and possibly adjusted airgap to get maximum inductance at desired current rating.
My friend uses this in his Hiraga amp . I think he asked Lundahl to make it suitable for 2,75 A with coils in parallel. The standard one is 750 mH 2A .
Making it choke input could be even better but you must take care of the minimum current to make it work as a choke input all the time even with no amp connected.
Greetings Eduard
Hello,
Just putting lots of microfarads can be done without spending loads of money.
But you have to use the ones from reputable dealers. If you will put to many you will give your transformer and rectifier a very difficult task.
Much better to create a crc or clc network like Hiraga did or like the 50 watt Kaneda designed / described by William Walther in the French Audiophile magazine decades ago. That one used CLC with a 200 mH choke.
My friend used Tent shunts for the input stage of his 20 watt Hiraga amp very compact and easy to install right at the input stage.
Greetings Eduard
Just putting lots of microfarads can be done without spending loads of money.
But you have to use the ones from reputable dealers. If you will put to many you will give your transformer and rectifier a very difficult task.
Much better to create a crc or clc network like Hiraga did or like the 50 watt Kaneda designed / described by William Walther in the French Audiophile magazine decades ago. That one used CLC with a 200 mH choke.
My friend used Tent shunts for the input stage of his 20 watt Hiraga amp very compact and easy to install right at the input stage.
Greetings Eduard
Surely a soft start and delay solved the problems wrt large capacitance? Also what’s a tent shunt?
Thanks, lc is a very good alternative. I think the best thing to do is try and experiment with crc , clc , regulated power supply, smps and see how they behave. I'll look for Kaneda, I remember his famous preamplifier. Again thanks.
Hello,
The soft start will prevent the fuse to blow but there will still be a an on/of switching with current peaks much higher than the average current. In the attachment it is just a modest 180 mA which already has peaks up to 425 mA.
By introducing an input choke the current being drawn will be close to 180 mA ALL the time and the ripple will be smaller with a much nicer '' shape '' as you can see in the left picture.
A Tent shunt is a tiny circuit by a famous Dutch designer that is not series but shunt regulated. Just google.
Greetings, eduard
The soft start will prevent the fuse to blow but there will still be a an on/of switching with current peaks much higher than the average current. In the attachment it is just a modest 180 mA which already has peaks up to 425 mA.
By introducing an input choke the current being drawn will be close to 180 mA ALL the time and the ripple will be smaller with a much nicer '' shape '' as you can see in the left picture.
A Tent shunt is a tiny circuit by a famous Dutch designer that is not series but shunt regulated. Just google.
Greetings, eduard
Hello,
This was published in 1988 in french l'Audiophile magazine #43 written by Mr Johannet and Mr Walther
The choke was a 200mH model 0,7 ohm dcr. I used it in my 30 watt Hiraga and it was first used in Le Nemesis ( single ended transistor amp by Jean Hiraga.
Right drawing
#1 the shape of the '' dc '' at the first cap
#2 the shape at the second cap when using CRC
#3 The shape at the second cap when using CLC.
Pretty obvious. RC is only 6DB and LC is of course a 12 DB filter.
Greetings, eduard
Hello,
IF i would make a le Monstre/20 watt Hiraga or a single ended Nelson Pass design i would surely try LL2771 for choke input( maybe another Lundahl if it will have sufficient enough mH for a choke input and probably Tent shunt for input stage.
I have used choke input in many different builds and i expect it to work in class A power amps too.
The 50 watt Kaneda used a regulated supply for input stages too.
You will have to try to be sure.
Greetings, eduard
IF i would make a le Monstre/20 watt Hiraga or a single ended Nelson Pass design i would surely try LL2771 for choke input( maybe another Lundahl if it will have sufficient enough mH for a choke input and probably Tent shunt for input stage.
I have used choke input in many different builds and i expect it to work in class A power amps too.
The 50 watt Kaneda used a regulated supply for input stages too.
You will have to try to be sure.
Greetings, eduard