Hiraga "Le Monstre"

[kenev]

As of today, I can boast that I also have a Le Monstre amplifier, currently in the JLH69 box and with its regulated, +/- 19V supply, current through the output transistors is 1A, transistors are 2SK170 / SJ74 + 2SC3324 / SA1312, 2SC3467 / SA1370 and output pair 2SC4467 / SA1694.
It works perfectly, I'm satisfied. The sound is great. It's not like my version of the JLH69, but I've been working on it for almost a year to perfection, I also need to give Le Monster a chance, I still have plenty of transistors to try, though it sounds great as well.

Great job!
Just a quick question: Since this amplifier is in my future plans, what PCB design did you use for your build?

 

[grunf]

Great job!
Just a quick question: Since this amplifier is in my future plans, what PCB design did you use for your build?

I do PCB design by myself, a true d.i.y. 🙂

in the first picture above is a PCB of JLH69, below is a PCB for Le Monstre

 

[sfltrack]

Did you get your problems sorted with the Serbian kit? I purchased on and the 5w, resistors run extremely hot and the voltage drop from the power supply seems excessive - from 12.6 volts when not hooked to the boards down to 6.8volts when running.

 

[grunf]

Did you get your problems sorted with the Serbian kit? I purchased on and the 5w, resistors run extremely hot and the voltage drop from the power supply seems excessive - from 12.6 volts when not hooked to the boards down to 6.8volts when running.

I don't know, I didn't see that KIT from Serbia, maybe something was wrong-fused on PCB or something was short-circuited or maybe it had some fake part. These are high currents when there is so much voltage drop, over 6A.
Put a picture of the PCB so we can see the transistors.

 

[sfltrack]

The parts look legit and I used input jfets from DIY audio store (linear systems matched)

The ebay listing is here:

https://www.ebay.com/itm/Hiraga-Le-...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2648

 

[grunf]

maybe some resistor has been replaced.
is it the same problem on both channels?

 

[sfltrack]

I checked all resistors before assembly. Both channels run the same.
Thanks

 

[sfltrack]

I got the answer. The voltage across the 1watt resistors was lowered from 6v to the proper .58 volts by modding the 1K bias resistors with parallel 470ohm resistor. I found out how to set the quiescent current from an old publication on the original amp.

 

[Mamak]

hiraga sound problem

Hi all,
I build hiraga amp 2 channel using below schematic. Sound is good.
But last week i have issue for one channel.Sound like not enough power(hard to say,still have song).Another channel work excellent.

I measure at red point is -5.05V. Can somebody guide me to troubleshoot this amp?

One more question how to set bias this amp using trimmer?what value of trimmer pot ?

Thanks

 

[jameshillj]

Hi "grunf"
Could I ask for some details of the regulator circuit that you used, and will it work for the 30W version?

 

[Mamak]

It is fully possible to increase to +16/-16 supply.
This almost doubles the power output.
Bias should be increased to 1.0 Ampere

Like here. See image.
THD 0.200% 10.75 Watt +16/-16 Volt supply
compared to 5.87 Watt with +12/-12 supply

Hi,what software you use for circuit simulation?

 

[Farhadt]

Hi everyone, I boult jh 30w, now I need a protection pcblayout...

 

[grunf]

Hi "grunf"
Could I ask for some details of the regulator circuit that you used, and will it work for the 30W version?

I made this regulator for my version of the JLH69 amplifier.
The output voltage can be adjusted, tested at 4A, with a minimum voltage drop of 3 V. It is a high-current version of Walt Jung's superregulator.

https://www.diyaudio.com/forums/solid-state/3075-jlh-10-watt-class-amplifier-563.html#post5972683

https://www.diyaudio.com/forums/solid-state/3075-jlh-10-watt-class-amplifier-580.html#post6050539

 

[grunf]

Hi,what software you use for circuit simulation?

My Le Monstre works at +/- 19V, at 14W at 8ohm distortion should be about 0.2%. The current is 1A.

 

[Mamak]

My Le Monstre works at +/- 19V, at 14W at 8ohm distortion should be about 0.2%. The current is 1A.

Thanks for reply,
Which component i need to change to use +-16V POWER SUPPLY?
Using below circuit.

 

[gaborbela]

You should go back to the original Hiraga Class A (low power version). This is over 30W and it was modified based on that.
Take a look at these schematics.
You get the idea of how many changes you need. I prefer the second schematic over the first. I built and tested both!

 

[Mamak]

You should go back to the original Hiraga Class A (low power version). This is over 30W and it was modified based on that.
Take a look at these schematics.
You get the idea of how many changes you need. I prefer the second schematic over the first. I built and tested both!

Oh no..difficult to me to modified.🙁.
Some body can guide me?Can only change zener diode?

 

[Mamak]

Oh no..difficult to me to modified.🙁.
Some body can guide me?Can only change zener diode?

I think i need to change red component.Zener diode 22 to 12v.And resistor from 4.7k to 10k for run in 16v dual power supply.
Which resistor control bias?

 

[U230421]

Which resistor control bias?

There is not a single resistor which controls or set the bias, it is a compound circuit. When changing the value of the power rails, you better calculate everything again. But keep the first stage on the original lower (zener-) value. No need to change that (save the series resistor in value and dissipation).
Settings are mainy with the collector resistances.

 

[androa76]

Grunf
Nice work.
I see that you used ZLJ capacitors in Hiaraga and FC and KMG or some others at JLH. ZLJ are quite *dry* and little *light* e sounding compare to for example Muse ore Silmic . Also FC that you used at JLH are for my ears fuller and little rounded. If sound is little sharp than maybe try other caps.