Thank you.
The "real" input pair appears to be a common base circuit. I learned about this configuration in school, but have never seen it used in a linear audio amplifier. It has a low impedance input and low gain compared to a common emitter circuit. I never gave it any thought for an audio amplifier application.
That's what I was thinking. 😉 It is quite a departure from conventional industry standards.
Guys,
If you want your Hiraga to sound even better, try replacing the zeners 22V with a regulated power supply +-22V. The result is even more headroom and much crearer sound.
Give it a try! I did this and the result is unbelievable!
If you want your Hiraga to sound even better, try replacing the zeners 22V with a regulated power supply +-22V. The result is even more headroom and much crearer sound.
Give it a try! I did this and the result is unbelievable!
How about a shunt with TL431?
- [I saw some noise on the output with this chip but less than a zener]
- In other preamps, I have had success with feeding the output through a small choke to take out HF noise [ such as 1 uH/10uF]. Here being on the collector it is reduced by at least 40 db.
I did it with the SSR03 regulator by Per Anders Sjostrom. Nice device and clean power. Don't know about the TL431. The SSR03 uses the LM431 or LM329. Opamp is AD825.
Check this out: http://www.diyaudio.com/forums/group-buys/241251-group-buy-ssr03-super-regulator-power-supply.html
Typo. TL431=LM431 🙄
Alone the LM431 has some noise left but with a small 1mH choke you can filter it all out.
That big Sjoström board looks a big big and costly (>> 50€?) for getting the sub-power for the input collectors to me!
Hiraga made good amplifiers.
If you have any questions on this amplifier, then ask.
Because Hiraga is certainly worth building!
🙂
If you have any questions on this amplifier, then ask.
Because Hiraga is certainly worth building!
🙂
Hiraga
Hi lineup,
All the best for 2014! And I couldn't agree with you more. The amp sounds better than anything I have heard, if built right ofcourse.... Did you build a lot of them? 🙂
Hi lineup,
All the best for 2014! And I couldn't agree with you more. The amp sounds better than anything I have heard, if built right ofcourse.... Did you build a lot of them? 🙂
Thanks. I did not build, but I was active in this topic.
This Hiraga is not so difficult to build.
But there are always details to be careful with.
Especially Hiraga needs a good clean supply.
This Hiraga is not so difficult to build.
But there are always details to be careful with.
Especially Hiraga needs a good clean supply.
Hi there
I have an old Hiraga 20/30W amp. The poor amp died because of a shorting of the output.....
I've been trying to repair but has only generated smoke so far.
I've found this schematic.
http://diyaudioprojects.com/Solid/Jean-Hiraga-Class-A-Amplifier/Jean-Hiraga-Super-Class-A-Amplifier-Schematic.png
I know that some of the transistors a rare as hens teeth.
I would use BC550/BC560 for the input.
I would use MJE15030/MJE15031 for the driver stage.
Finally MJL4281/4302 for the output.
As far as I remember the power supply is outputting +/-28V regulated.
Can any one tell me if I need to change any other components because the original schematic uses +/- 35V regulated.
Best Regards
Jan Jepsen
I have an old Hiraga 20/30W amp. The poor amp died because of a shorting of the output.....
I've been trying to repair but has only generated smoke so far.
I've found this schematic.
http://diyaudioprojects.com/Solid/Jean-Hiraga-Class-A-Amplifier/Jean-Hiraga-Super-Class-A-Amplifier-Schematic.png
I know that some of the transistors a rare as hens teeth.
I would use BC550/BC560 for the input.
I would use MJE15030/MJE15031 for the driver stage.
Finally MJL4281/4302 for the output.
As far as I remember the power supply is outputting +/-28V regulated.
Can any one tell me if I need to change any other components because the original schematic uses +/- 35V regulated.
Best Regards
Jan Jepsen
As far as I can see there is no changes needed for 28/28 Volt supply.
The difference between 28 and 35 is rather small,
You can go on follow that schematic with those transistors.
The difference between 28 and 35 is rather small,
You can go on follow that schematic with those transistors.
Hiraga
Hi Jan,
As long as you don't go lower than 24VDC the list is OK. But you might want to change some small things: 47K resistors to say 33K. 1K resistors to say 1.5K. That should do the trick!
Hi Jan,
As long as you don't go lower than 24VDC the list is OK. But you might want to change some small things: 47K resistors to say 33K. 1K resistors to say 1.5K. That should do the trick!
Thank you the replies !!
Regarding the heatsink....would this one do the trick for the 15030/15031 ?
And while asking....if the powersupply turns out to be 24V ?
Best Regards
Jan Jepsen
Regarding the heatsink....would this one do the trick for the 15030/15031 ?
And while asking....if the powersupply turns out to be 24V ?
Best Regards
Jan Jepsen
I link would complete the story......
Kb Kleplader Heatsink SK76 50mm 7K/W TO220 Fischer Elektronik SK76-50-TO220 online fra RS.
Best Regards
Jan Jepsen
Kb Kleplader Heatsink SK76 50mm 7K/W TO220 Fischer Elektronik SK76-50-TO220 online fra RS.
Best Regards
Jan Jepsen
BC550C BC560C is better.
Always buy "C", because they have higher gain
and so they are suitable for Audio.
For other non-audio projects you can use BC550B/BC560B and BC547B/BC557B
Always buy "C", because they have higher gain
and so they are suitable for Audio.
For other non-audio projects you can use BC550B/BC560B and BC547B/BC557B
I will use the C version.
And I was right about the power supply. +/- 27.8V. All should be well.
So it's off to the workshop.
Thank you for the help so far !!!!
Best Regards
Jan Jepsen
And I was right about the power supply. +/- 27.8V. All should be well.
So it's off to the workshop.
Thank you for the help so far !!!!
Best Regards
Jan Jepsen
Heatsinks
Those are OK 😎
I look forward to the pictures of your build! 😛
Happy soldering!
Those are OK 😎
I look forward to the pictures of your build! 😛
Happy soldering!