Le Monstre it has an amplification of about 26dB (x20) while the M2 only has 14dB (x5), so that's why you hear the noise of the preamp that you didn't hear before. Reduce the 220k resistor below 47k and try again.
For Le Monstre, about 1.3Vp-p is enough for full power, so it doesn't need a preamp with a good source.
I drive mine only with my DAC, which has an output voltage of 8.64Vp-p or 3.02Vrms only through a passive of P&G 10klog slide pot .
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They have been out of production for 20-30 years, so if you get some, they are probably fake...
.. But what does the 'Y' imply /mean? I had assumed it was French shorthand for matched/ selected etc, but that's not the case
Hello,
Surely
The French company selling them surely was not big enough to get them closely matched.
Most of the time most of the Japanese parts they were selling were out of stock.
Greetings Eduard
So the 'Y' means lowest IDSS (bottom of the spec sheet)
I'm assuming this gives the lowest noise?
I'm assuming this gives the lowest noise?
No, for 2SJ74: The higher drain current, the lower noise. It's about the same for 2SK170, but for a drain current larger than about 4 mA, the difference is smaller.
But remember that the transconductance is about proportional with the square root of the drain current. This means that the original Monster has a higher open loop gain with the original transistors than what is obtainable with the GR or BL FETs.
I select from about 200 GR as low as possible, that means around IDSS 3.0, and lower down 1K resistor to around 750 ohm (in some circuit diagrams R2/3).
Thats ended into around 600 mA through the 2SD844 / 2SB754
Thats ended into around 600 mA through the 2SD844 / 2SB754
Anybody who has built this Hiraga 30W using prasi's pcb?
What transistors are you using?
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I have a Super 30w but with the PCBs and all the original parts (the audiophile's house), I can't help you with the Prasi boards.
on the other hand, I can tell you that it is an excellent amp, very sensitive to its power supply.
I had made a first assembly with a simple power supply before receiving my order of 6 x100000uF, the amp was very different afterwards.
It's been with a friend for 15 years and we even use it to have dance parties with Cabasse Sampans lourd.
on the other hand, I can tell you that it is an excellent amp, very sensitive to its power supply.
I had made a first assembly with a simple power supply before receiving my order of 6 x100000uF, the amp was very different afterwards.
It's been with a friend for 15 years and we even use it to have dance parties with Cabasse Sampans lourd.
Almost the same with 2uF 160V in parallel with the last two and 26 Vdc.
No soft start, and just DC protection at the output (Velleman)
I check it every 4 or 5 years (during the aperitif) and it has never moved.
look on the net, there are a lot of topics on the evolution of 20 and 30w depending on the times, transistors and supply voltages (especially in France).
Now i know the way for bias setting 😉
I need to reduse 27K7(47K//68K) even farther for +/-24v .
Keep in mind that i have a test heatschink (small).
I will go for the second channel and then i will have a listening test.
From a first,mono test,not bad.☺️
I need to reduse 27K7(47K//68K) even farther for +/-24v .
Keep in mind that i have a test heatschink (small).
I will go for the second channel and then i will have a listening test.
From a first,mono test,not bad.☺️
Hello,
Jean Hiraga wrote about le monstre when it first appeared in Japan being a small power amp with a big power supply.
In the famous French magazine appeared some articles about pimping the power supply. It was the general idea back then if you dont need a lot of power le monstre works very well. A bigger/ better power supply would make it sound more powerful.
The 20 and 30 watt were designed by Hiraga ( maybe based upon another design, i forget) . At least he and his " crew " in France spend loads of time making it better or making changes when certain parts ( drivers and output transistors disappeared from the market )
Since then there have been people who think they could do the same using a similar topology, other resistors, transistors, potentiometer, power supply caps turning it into an amp which is not an Hiraga anymore.
Greetings,Eduard