Hi,
I tried your version but only with IRFP240/9240 and BD as drivers - THD is less - about 0.1-0.2% at the same level with 14V rails. BC show bigger THD then BD or MJE 15031/30.
I tried your version but only with IRFP240/9240 and BD as drivers - THD is less - about 0.1-0.2% at the same level with 14V rails. BC show bigger THD then BD or MJE 15031/30.
Hello
If you do not like the BC550C/560C as a driver try to use the same driver I'll will use in the mosfet version.
Greetings
If you do not like the BC550C/560C as a driver try to use the same driver I'll will use in the mosfet version.
Greetings
So you say the mosfet version is better after the sim??
I built the Le Monstre with the orig parts a couple years a go but the Class A sounded way better!
That is why I want to try these mosfet version. Something different!
Thank you
You can get those drivers easily
Greetings Gabor
I built the Le Monstre with the orig parts a couple years a go but the Class A sounded way better!
That is why I want to try these mosfet version. Something different!
Thank you
You can get those drivers easily
Greetings Gabor
For me it looks like it. I swapped only the output transistors (with gate stoppers and add 510R Resistor Between drivers collectors).
THD drops from 0.5 to 0.118 % in sim.
THD drops from 0.5 to 0.118 % in sim.
Yes you are right!!!?!?!
http://www.audio-constructions.com/monstre/DSC04059.png
I have mounted it as first suggested and it works! Mayby that is the reason for the shy bass?
But then should it work at all the other way round?????
Have I burned out them?
Why should it work the wrong way? Mine works the wrong way indeed but maybe this is the reason for the "shy" bass?
Can I use the same fets of are they burned out because of the wrong way connected?
Hello
I don't think your JFet is burned! It would not work at all if you burn the JFets.
I had similar issue with my Monstre. Shy bass! That is why I want to try the mosfet version.
My advise try to remove the electrolytic from the PC board and use only some good PIO (paper in oil) or teflon capacitors 1uF or so.
Greetings
I don't think your JFet is burned! It would not work at all if you burn the JFets.
I had similar issue with my Monstre. Shy bass! That is why I want to try the mosfet version.
My advise try to remove the electrolytic from the PC board and use only some good PIO (paper in oil) or teflon capacitors 1uF or so.
Greetings
The correct connection of the FETs is this one.
Only the 2sk170 needs to be reversed.
Please confirm if I am right, to avoid further confusion.
Only the 2sk170 needs to be reversed.
Please confirm if I am right, to avoid further confusion.
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Hello
Try to use Russian PIO K40-Y9 type or Teflon caps without the Cerafines.
Just give a try please.
I have a simple Class A amp ,I used PIO and I tried to replace it with Silmic.
It got 10 time worst sound, specially in bass..
Silmic one of the best caps in bass , and when I used only PIO much better. Different amp!
By the way nice layout design. It is your design?? I will use it..Thanks!
Greetings
Try to use Russian PIO K40-Y9 type or Teflon caps without the Cerafines.
Just give a try please.
I have a simple Class A amp ,I used PIO and I tried to replace it with Silmic.
It got 10 time worst sound, specially in bass..
Silmic one of the best caps in bass , and when I used only PIO much better. Different amp!
By the way nice layout design. It is your design?? I will use it..Thanks!
Greetings
Yes I have used these russian teflons in parallel with cerafine.
The layout is of another guy here in the forum but please note about the changes.
Please confirm if only one of the two fets needs to be reversed, or not. I am waiting for a reply for the other members on this on my post above.
If only one of the two needs to be reversed then it would be nice to have the pcb altered so that thermal equilibrium occurs between the two fets again. I have allready made the faulty PCBs so I cannot correct this now...
Hello Neazoi,
Source pins of the JFets must be linked to the 100ohm trimpot; drain pins must be linked to the resistor drain of 1k via the bipolar of the cascode (2SC1175/2SA872). Please check the datasheet of the JFet for correct pins identification, but in my memory you've got to reverse both.
Indeed, a Jfet can "work" wrong way, because its internal structure is more or less symetrical. You may measure same idss both way. For me, i match my trans with a curve tracer and a difference occurs with the choice of connection.
Anyway, i don't think your JFet have suffered.
Don't think neither that they are responsable for your "shy bass".
This last point is very strange !
Le Monstre was known to have exceptional, firm, quick and powerful bass, comparable to the Kaneda 50W. I have never heard a "shy" le monstre in bass, oh no !
This power is coming also from the huge PSU : the different versions used between 500000µF and 1.2F per way with or without battery (for perfect silent PSU). You use only 1000µF...Do a test with 300000µF, you may hear something different.
Knd Rgds
PYJ
Source pins of the JFets must be linked to the 100ohm trimpot; drain pins must be linked to the resistor drain of 1k via the bipolar of the cascode (2SC1175/2SA872). Please check the datasheet of the JFet for correct pins identification, but in my memory you've got to reverse both.
Indeed, a Jfet can "work" wrong way, because its internal structure is more or less symetrical. You may measure same idss both way. For me, i match my trans with a curve tracer and a difference occurs with the choice of connection.
Anyway, i don't think your JFet have suffered.
Don't think neither that they are responsable for your "shy bass".
This last point is very strange !
Le Monstre was known to have exceptional, firm, quick and powerful bass, comparable to the Kaneda 50W. I have never heard a "shy" le monstre in bass, oh no !
This power is coming also from the huge PSU : the different versions used between 500000µF and 1.2F per way with or without battery (for perfect silent PSU). You use only 1000µF...Do a test with 300000µF, you may hear something different.
Knd Rgds
PYJ
Hello
Yes you have to turn both both JFet.
I agree with jouff about the "shy bass" .
If you already has the PC board that is not a problem. Use a piece of heat-shrink and fill up the empty place with that warm glue.
You know that glue you have to melt it with glue gun. That has very good thermal conductivity!
Also try to play with different hockup wires. These amplifier is very sensitive to every parts U use.
Greetings gabor
Yes you have to turn both both JFet.
I agree with jouff about the "shy bass" .
If you already has the PC board that is not a problem. Use a piece of heat-shrink and fill up the empty place with that warm glue.
You know that glue you have to melt it with glue gun. That has very good thermal conductivity!
Also try to play with different hockup wires. These amplifier is very sensitive to every parts U use.
Greetings gabor
Seeing the datasheets and the schematic http://www.audio-constructions.com/monstre/Hiraga-Monstre-Monster-Class-A-amplifier-schematic.png I think only one of the two fets needs to be reversed.
Is that right? please check it
