Hiraga "le monstre"

[Lumba Ogir]

Sigurd,
I`m really surprised by your instant interest. Are you sure? Is this thread appropriate for those considerations?

[Sigurd Ruschkow]

Lumba -

you have interesting ideas and some of them clash with mine, and THAT makes things interesting.

Not sure if this thread is the appropriate one. If your design is a Hiraga-style le monstre, I would say that it is fine.

You of course always open up a new thread.



Regards,
Sigurd

Originally posted by Lumba Ogir
Sigurd,
I`m really surprised by your instant interest. Are you sure? Is this thread appropriate for those considerations?

[bluevas]

Hi guys,

I plan to make power supply for my Le Monstre using Kaneda power supply based on post 19 on page 1 this thread, but could anybody help me explain or give me picture the pin of 2SK30GR on both positive and negative supply, especially 2SK30GR on the negative supply which uncorrect?

Thank you Gentlemen,
Best Regards,

Josh

[lineup]

Originally posted by bluevas
Hi guys,

I plan to make power supply for my Le Monstre using Kaneda power supply based on post 19 on page 1 this thread, but could anybody help me explain or give me picture the pin of 2SK30GR on both positive and negative supply, especially 2SK30GR on the negative supply which uncorrect?

Thank you Gentlemen,
Best Regards,

Josh

I have spiced a version of this Hiraga Monstre
with transistors that are a bit more 'modern' and can be found to buy.
I feel a bit guilty for given a less good advice to a guy.
I said: do not change and lower 1 Ohm resistor if you want to use higher Class A current.

My sim testing shows it is Very much good
to for example use parallell 1 Ohm // 1 Ohm, for higher currents in output.
Of course some additional increase of current in previous driver stage
is then to recommended.

This comes from the fact we benefit from higher voltage gain in output stage.
for example:
Speaker 8 Ohm / (1 Ohm//1 Ohm) = Vgain 16
Using four 1 Ohm resistors instead of 2 gives:
8 Ohm / ( 1 Ohm / 4 ) = Vgain 32

In short: doubled Voltage gain.
This is needed + good, as well as lower voltage drop across these Emitter resistors is a positive thing.

If anyone want me to
I post my optimal version of this great Hiraga Monstre Puure Class A amplifier.

Regards, Lineup
---------------------------------------
-------------------------------------------------

PS.
A MOSFET Class A amplifier with same output stage idea
is

the wellknown Zen version 5 ( Zen v5 )
by Nelson Pass.
http://www.passdiy.com/amps.htm
http://www.passdiy.com/pdf/zen-v5-hires.pdf ( 1.6 MB )
http://www.passdiy.com/pdf/zen-v5-lowres.pdf ( 500 kB )
This is one of my absolute favourites !!!
of All the many Nelson Pass Class A MOSFET projects

[danieljw]

post away lineup, it will be interesting to see your take on Le monstre.

-Dan

[hifidaddy]

Originally posted by bluevas
Hi guys,

I plan to make power supply for my Le Monstre using Kaneda power supply based on post 19 on page 1 this thread, but could anybody help me explain or give me picture the pin of 2SK30GR on both positive and negative supply, especially 2SK30GR on the negative supply which uncorrect?

Thank you Gentlemen,
Best Regards,

Josh

Hi Josh,

yes the gate of the SK30 on the negative supply should be placed to negative raw voltage, that means at the other side of the transistor.
The SK30 is symmetrical, in the mid there is gate, and the other leads are source and drain, and you can reverse source/drain with SK30.

best regards, Hartmut from Munich

[lineup]

Originally posted by lineup

I have spiced a version of this Hiraga Monstre with transistors that are a bit more 'modern' and can be found to buy.
----------------------
If anyone want me to I post my optimal version of this great Hiraga Monstre Pure Class A amplifier.
Regards, Lineup

Originally posted by danieljw
post away lineup, it will be interesting to see your take on Le monstre.
-Dan

Here you are, Daniel.

Some points:
- My spice testing shows, that for 8 Ohm speakers,
the original Hiraga idle current 0.8 Ampere, is a good level
- Mathematically:
0.8 A in push-pull gives max output current = 2x0.8 = 1.6 A
1.6 A x 8 Ohm = peak Voltage out +- 12.8 Volt.
- Which, using a dual 12 VDC supply should be enough.

It should be noted, that using Higher Idle Current bias, than you need,
will most often give more distortion, instead of any improvement.
=========================================

- Transistors in my May 2008 final version ( was doing this one day 1 month ago, 2008-05-31 )
input:
2SK170GR + 2SJ74GR .. IDSS is ~ 4-5 mA
... no problem using them without cascode, as 2SJ74 takes 25 Volt.
- But I added cascode at 6Volt level (half supply) with:
BC560C + BC550C
I do not remember, but probably this gives a bit lower distortion.
I usally avoid cascoding JFETs, unless I see there is some benefit from it.
- Second stage, drivers.
BD139 + BD140
Nothing mysterical. They are the best bang for buck drivers ever made and used in audio.
In this amplifier, Le Monstre, they will fit in very well regarding quality.

- Output transistors.
TIP41 + TIP42
I started out testing with MJ15024 + MJ15025 = TO-3 high power.
But these TIP41/TIP42 OnSemi devices performs better.
Probably because they have higher gain.
Rated 65 Watt and as they will only dissipate like 0.8 x12-15 VDC = 10-12 Watt for Class A,
there is no problem using these easy to find & budget price devices.
They are marketed as:

6 Ampere Complementary Silicon
Plastic Power Transistors
Designed for use in general purpose amplifier and switching
applications.
Datasheet: TIP41/TIP42, PDF
.

My first attachment.
Shows that we can possibly squeeze out like 6 Watt RMS
with very low distortion, into 8 Ohm speakers.
This is not bad
When we think of 12 Volt supply & that this means Output is at:
- 9,80 Volt peak
- 1,225 Ampere peak ~ 76% of max ( theoretical max = 1.6 A )

Lineup

[danieljw]

very nice lineup,

interestingly my le monstre puts out approx 6 watts RMS just like the sim

it is surprising how far 6w goes, however i am building the higher power Le class A (upgraded output stage) at the moment.

-Dan.....

[Lumba Ogir]

lineup,
unfortunately, I am less impressed expecting a sonic performance far from the original. Many deteriorating parts, especially the extended Cob of the VAS is extremely muddying. So it`s definitely not an improvement, rather an abuse of the beautiful original idea.

BD139 + BD140 Nothing mysterical. They are the best bang for buck drivers ever made and used in audio.

explicitly wrong, not to be used for voltage amplification.

[lineup]

Originally posted by danieljw
very nice lineup,

interestingly my le monstre puts out approx 6 watts RMS just like the sim

it is surprising how far 6w goes, however i am building the higher power Le class A (upgraded output stage) at the moment.

-Dan.....

The 6 Watt level, as being the limit, when using 0.80 A bias, is not surprise to me.

I have setup many such Class A amplfiers. Of very different circuits.
But most of the time such Class A have the same critical level, at where distortion begins to rise:
.. this is when Peak Output Current is between 75 - 85 % of theoretical Max
In this case was 1.2 A out of 1.6 A ( 2x 0.8A ).


Conclusion:
-------------------------------
When designing Class A amplifier, a good bias target value is:
1.33-1.25 x The max output current the amplifier will deliver


Regarding Lumba Ogir comment.
I don't take it too much serious and I am not very bothered. I have seen it looks like Mr. Ogir likes to be ciritical. In fact, I can not remember any post where Lumba actually has been positive to some other peoples works. There is always some detail he find to bang down into the head of other posters
And I am quite sure Jean Hiraga had been much more positive, if see my circuit. At least if he would have had any points, I think he would have been able to explain himself better.

Lumba is right in one thing.
My version is not an original Hiraga Le Monstre.
In this respect, it is probably like most of those 'Le Monstres' built today.
But my version is an attempt to try to improve on Hiraga's good idea. Using some of today's common and affordable transistors.
This makes my circuit a Lineup Class A, a la Hiraga Monstre.
If this is good or not, is much up to the many readers here to decide.

Lineup