Jean Hiraga Le Monstre 8 Watts Class A Amplifier

[radium7]

After I start building Vacuum Tube based Amp and preamp, I didn’t build any SS amp except repairing few SS amps and preamps. But I am interested in building some good SS Amps like Jean Hiraga and Pass Lab design. Now I got a chance to build the famous Jean Higara Le Monstre 8 Watts Class A Amplifier. Long time ago I tried this circuit with some locally available components, but now I decided to use high quality components.

One of my friend wanted to build SS Class A Amplifier, we took Jean Hiraga “Le Monstre” and Pass Lab “Alpha J” circuits and discuss about it and decided to build Le Monstre 8W Amplifier. I placed order for PCB’s and Components, I decided to go for original circuit without any modification and same parts recommended by jean hiraga. I got them from some genuine sellers, hope they are good.

I have good heat sinks removed from a power supply units of a industry. Regarding power supply I decided to use 22000uf / 35V X 10 capacitors and I am looking for Keltron capacitors, but it is difficult to get here in chennai. If any one know the source to get Keltron caps pls share details.

 

[manir]

I got them from some genuine sellers

Super...
I also have dream to get one Le Monster
please let us know the sellers and how to get this PCB and components?

Jims Audio PCB?

 

[drlowmu]

After I start building Vacuum Tube based Amp and preamp, I didn’t build any SS amp except repairing few SS amps and preamps. But I am interested in building some good SS Amps like Jean Hiraga and Pass Lab design. Now I got a chance to build the famous Jean Higara Le Monstre 8 Watts Class A Amplifier. Long time ago I tried this circuit with some locally available components, but now I decided to use high quality components.

One of my friend wanted to build SS Class A Amplifier, we took Jean Hiraga “Le Monstre” and Pass Lab “Alpha J” circuits and discuss about it and decided to build Le Monstre 8W Amplifier. I placed order for PCB’s and Components, I decided to go for original circuit without any modification and same parts recommended by jean hiraga. I got them from some genuine sellers, hope they are good.

I have good heat sinks removed from a power supply units of a industry. Regarding power supply I decided to use 22000uf / 35V X 10 capacitors and I am looking for Keltron capacitors, but it is difficult to get here in chennai. If any one know the source to get Keltron caps pls share details.

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The " Entree " Portion of that schematic : After you build it, I am no expert, but would GUESS the 1.2K and 47K parts are CRITICAL as to their effect on the overall listening results.

WHY ?? Common sense. They are the lowest signal level in the amp, and they " set the stage" for any possible fidelity goodness that follows, since they are right at the beginning.

I would suggest to AURALLY experiment with both those two resistive positions !!

Besides initially listening to Hiraga's part suggestions, I would TRY the best resistive parts possible - right there.

First of all, I would DOUBLE and PARALLEL each resistor position !! That is right, make the stock 1.2K " R1 " times two in parallel at 2.4K, each resistor, closely matched to each other in Ohmic Value ( 0.01% ). Listen to that one change ! Next do the same for what I will call R2, make it 94K Ohms ( up to 100K Ohms ) but within 0.01% matched to EACH OTHER. ( Matching avoids Ohmic SKEWING ).

So far, I personally prefer doubled Caddock TF020 resistors ( Michael Percy ) and they need 300 hours to fully break in .

Please, I am only GUESSING. If you listen - to - evaluate this, please be sure to personally contact me, to share with me your listening results. Thank you. It works great on all-out and excellent vacuum tube implementations. Try it with yours.

Jeff

 

[drlowmu]

I just noticed, there is a photo you posted of four pieces of black bodied 2.4K 0.5 W rated metal-film-looking resistors. It has " H4" printed on the resistor body. Is that by chance a HOLCO resistor????

If so, do not use it, get rid of it. You need better sounding resistors than that !!

If you want to P.M. me through HFV, we can try to find alternatives, affordable and better sounding.

Jeff

 

[manir]

Professor any updates?

 

[radium7]

Professor any updates?

Busy in few other work, Power transformer work not finished. Try to update soon.

 

[destino]

The " Entree " Portion of that schematic : After you build it, I am no expert, but would GUESS the 1.2K and 47K parts are CRITICAL as to their effect on the overall listening results.

WHY ?? Common sense. They are the lowest signal level in the amp, and they " set the stage" for any possible fidelity goodness that follows, since they are right at the beginning.

I would suggest to AURALLY experiment with both those two resistive positions !!

Besides initially listening to Hiraga's part suggestions, I would TRY the best resistive parts possible - right there.

First of all, I would DOUBLE and PARALLEL each resistor position !! That is right, make the stock 1.2K " R1 " times two in parallel at 2.4K, each resistor, closely matched to each other in Ohmic Value ( 0.01% ). Listen to that one change ! Next do the same for what I will call R2, make it 94K Ohms ( up to 100K Ohms ) but within 0.01% matched to EACH OTHER. ( Matching avoids Ohmic SKEWING ).

So far, I personally prefer doubled Caddock TF020 resistors ( Michael Percy ) and they need 300 hours to fully break in .

Please, I am only GUESSING. If you listen - to - evaluate this, please be sure to personally contact me, to share with me your listening results. Thank you. It works great on all-out and excellent vacuum tube implementations. Try it with yours.

Jeff

I'm curious. Is the purpose of using doubled resistors to get a resistor with twice the power handling or is there a performance advantage here? Also what is occurring in a passive component such as a resistor that it requires "breaking in"