I have assembled 2 versions of the amplifier, but not the original circuit. Printed circuit boards are designed for a specific application. If anyone offers a more perfect version of this amplifier, then perhaps I will repeat it. But don't increase the number of transistors.
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Great! You'll have a lot lower distortion, due to higher loop gain, so no "Hiraga sound" but it's worth trying, cloning is boring...
I have another way to increase the open loop gain, in my Mimir, se the schematic. It is done with the two resistors R17 and R18, which then means it is possible to reduce the value of R23 and R24.
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KHN Audio Mimir
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KHN Audio Mimir
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Input repeaters are not covered by the global NFB. Replacing current-setting resistors with current-stabilizing diodes (CRD) or current generators helps to reduce harmonic distortion.
The use of scale current reflectors as a load also contributes to the linearization of the amplifier.
The use of scale current reflectors as a load also contributes to the linearization of the amplifier.
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If you want the same listening experience with this amplifier as Hiraga himself, you would have to use the same components, the build should not be different, the preamplifier should be the same, nor should the loudspeakers, the cables, the room acoustics ....
I don't think this is possible, is it?
Why you insult people who try different options?
He did not claim that he built something better than Hiraga himself.
I built several versions including the one with the original semiconductors, guess what I dismantled the original and sold the semiconductors on Ebay.
It does not mean I built something better than Hiraga.
No, I never said that even do I preferred other modern transistors over the NEC.
Only means different wine different taste.
Same time hard to find those old semiconductors from Hitachi or NEC.
Yes, we own Mr. Hiraga for his design a lot but please consider all I mentioned availability, etc, etc.
One who wants to build the original and has the semiconductors for it that will find the original design (schematics) also.
No need to insult people or called their version rubbish. It is a DIY forum!!!
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Was just going through the posts from 2017 and I realized now that I never posted the pic of completed amps here! I'm enjoying the amps ofcourse with occasional tweaks here and there!
Thanks to wonderful people here for guiding me!
Passive Pre-amp at the top followed by 30W Hiraga Mono Blocks
Here is a link you small pictorial build log of my amps:
Class A Amplifier Jean Hiraga Super 30W Amplifier Build Log - YouTube
and here is a link on how it sounds :
Class A Amplifier Jean Hiraga Super 30W and Alpair 10.3M Full Range speakers part-2 - YouTube
Thanks to wonderful people here for guiding me!
Passive Pre-amp at the top followed by 30W Hiraga Mono Blocks
Here is a link you small pictorial build log of my amps:
Class A Amplifier Jean Hiraga Super 30W Amplifier Build Log - YouTube
and here is a link on how it sounds :
Class A Amplifier Jean Hiraga Super 30W and Alpair 10.3M Full Range speakers part-2 - YouTube
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Hello,
Even the older people having a hard time reading properly lol. A diy forum is clearly different from the original French text.
Hiraga was looking for a special sound during his design. If you use other parts or alter the circuit you will get something different that possibly pleases you more than one made exactly according to Hiraga publication.
Greetings,Eduard
Even the older people having a hard time reading properly lol. A diy forum is clearly different from the original French text.
Hiraga was looking for a special sound during his design. If you use other parts or alter the circuit you will get something different that possibly pleases you more than one made exactly according to Hiraga publication.
Greetings,Eduard
I too appreciate the jlh/ hiraga circuits I'm always amazed when a good recording is playing.
Here's the circuit board I showed schematic off, just finished drilling heatsinks today and have power tested them for two hours, bias is 1.65 amps and heatsink settles at 53 degrees Celsius, I think that's not to bad, will make some soundcard measurements tomorrow, and see how it behaves.
Here's the circuit board I showed schematic off, just finished drilling heatsinks today and have power tested them for two hours, bias is 1.65 amps and heatsink settles at 53 degrees Celsius, I think that's not to bad, will make some soundcard measurements tomorrow, and see how it behaves.
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OK. I am sorry. I am aware of the unavailability of the original parts. I meant to say that the "improvements" will result in increased instability and distortion. Making a good circuit design worse is not a great achievement.
By the way, I am far from convinced that the NEC devices were the best choice.
By the way, I am far from convinced that the NEC devices were the best choice.
I stated I tested the NEC VS ON Semi and sold the NEC drivers and power transistors also. I got overall more controlled sound, cleaner, much detail, and way better bass improved dynamics.
The NEC sounded tube-like but not a very high category tube sound. Got a warmer sound overall but less separation, less clearance and the rest were in favor of the ON Semi.
I have to mention my NEC power transistors were used, removed from an older JVC receiver.
The NEC sounded tube-like but not a very high category tube sound. Got a warmer sound overall but less separation, less clearance and the rest were in favor of the ON Semi.
I have to mention my NEC power transistors were used, removed from an older JVC receiver.
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