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Question of the amplifier circuit Jean Hiraga's Class-A
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Author:  Sample [ 15 Sep 2009, 14:10 ]
Post subject:  Question of the amplifier circuit Jean Hiraga's Class-A

Hello everyone!
I pick Jean Hiraga's Super Class-A Amplifier (http://diyaudioprojects.com/Solid/Jean- ... Amplifier/)
I have a question on the scheme, if there mistakes?
Lower diode RD22 is not connected with the resistor 1.1k, in contrast to the top.
Attachment:
Jean-Hiraga-Super-Class-A-Amplifier-Schematic.gif

Thank you in advance for your help!

Author:  Gio [ 16 Sep 2009, 20:20 ]
Post subject:  Re: Question of the amplifier circuit Jean Hiraga's Class-A

Thanks for pointing this out. Ironically another reader had noted this error as well as the polarity of the zener diode a few months back and while I had made the changes I forgot to upload the corrected schematic. Note that the zener diode polarity is incorrect on the original Hiraga schematic which appeared in L'Audiophile but it is shown correctly on the PCB image as well as on the (now corrected) schematic that we drew up.

If you guys note any errors on the site, just let us know and we will correct them.
Cheers.

Author:  Sample [ 17 Sep 2009, 05:19 ]
Post subject:  Re: Question of the amplifier circuit Jean Hiraga's Class-A

Thank you very much! :thumbsup:

Do you think, replacing 5200 and 1943 on the 2N5886 and 2N5884 will not cause problems? Easier for me to get a second pair!

Author:  Dan [ 17 Sep 2009, 07:06 ]
Post subject:  Re: Question of the amplifier circuit Jean Hiraga's Class-A

Hi Sample,
I would suggest if you replace the 5200/1943 with 5886/5882 the amp will operate fine, however the frequency response and speed in general will be a little slower based on the Cob of the 5886/58884 pair in comparison with the 5200/1943 pair.

-Dan

Author:  Sample [ 18 Sep 2009, 03:56 ]
Post subject:  Re: Question of the amplifier circuit Jean Hiraga's Class-A

Thank you, Dan! :)
Maybe I can try both pairs. Suffice interesting to compare! Moreover, the metal body would effectively removes the heat!

With best regards, Yuri.

Author:  Sample [ 22 Sep 2009, 07:53 ]
Post subject:  Re: Question of the amplifier circuit Jean Hiraga's Class-A

Hi!
Dan, tell me please, what Zener diodes (exact model name) you have used in the scheme?

With best regards, Yuri.

Author:  Sample [ 22 Sep 2009, 18:17 ]
Post subject:  Re: Question of the amplifier circuit Jean Hiraga's Class-A

Oops! Found! :?
http://www.datasheetarchive.com/pdf-dat ... 434064.pdf

Author:  CrazzyAbtTubes [ 22 Sep 2009, 18:35 ]
Post subject:  Re: Question of the amplifier circuit Jean Hiraga's Class-A

I have a power supply question for the 8 watt version of this amplifier.... I have two fully DC regulated 12V+ at 2A, 12V- at 2A(dual rail) power supplies that have really good noise rejection and would be perfect for a dual mono version of this amplifier, would these work?

Author:  Gio [ 24 Sep 2009, 15:49 ]
Post subject:  Re: Question of the amplifier circuit Jean Hiraga's Class-A

Hi Alan, in Jean Hiraga's article Le Monstre a 160 VA EI or C core transformer was suggested. Your supplies are only 48VA each.

Author:  CrazzyAbtTubes [ 24 Sep 2009, 16:22 ]
Post subject:  Re: Question of the amplifier circuit Jean Hiraga's Class-A

Yes, I do know that Gio, but I already have a 15V-15V 225VA Hammond turoid I can instead of the ones in the supplies, and the LM338K regulators are rated at 5A, but in this case I am using two supplies rather than just one, I am also pretty sure these are capable of a continuous 2A per rail with the addition of a bit more heat sinking.

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