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Question of the amplifier circuit Jean Hiraga's Class-A
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Author:  Gio [ 11 Feb 2018, 20:38 ]
Post subject:  Re: Question of the amplifier circuit Jean Hiraga's Class-A

Hello and welcome to the form.

Only one channel (mono) is shown on the schematic so you can duplicate the circuit for stereo.

Both toroid and EI core ("normal") transformers will work just fine.

Author:  gh0st3g [ 02 Jun 2018, 05:06 ]
Post subject:  Re: Question of the amplifier circuit Jean Hiraga's Class-A

Hello guys,
I woukd like some help from you.
I am goung to build one, but there is something about capacitor on power supply.
Should i place 330,000 uf insteed of 220,000 uf.
Follow the schematic firt capacitor 220,000 uf then registor then two 220,000 uf. Now i am going use 330,000 uf then registor and one 330,000 uf.
Could it be like this?
Thanks for all your help.
Regards,

Author:  Yungman [ 02 Jun 2018, 14:47 ]
Post subject:  Re: Question of the amplifier circuit Jean Hiraga's Class-A

gh0st3g wrote:
Hello guys,
I woukd like some help from you.
I am goung to build one, but there is something about capacitor on power supply.
Should i place 330,000 uf insteed of 220,000 uf.
Follow the schematic firt capacitor 220,000 uf then registor then two 220,000 uf. Now i am going use 330,000 uf then registor and one 330,000 uf.
Could it be like this?
Thanks for all your help.
Regards,


You mean the schematic use 22,000uF, then a resistor, then TWO 22,000uF in parallel?

Unless you have a good reason, I would stay with two 22,000uF in parallel.

the reason is two smaller value cap in parallel is usually ( say always) better than one single big cap. The bigger the cap, the higher the ESR and ESL. Two smaller cap in parallel with lower the ESR and ESL by half.

I design my amps using over 10 of the 10,000uF in PARALLEL to get the very low ESR and ESL. Hiraga is a high quality amp, I would not mug with this.

Author:  gh0st3g [ 03 Jun 2018, 05:27 ]
Post subject:  Re: Question of the amplifier circuit Jean Hiraga's Class-A

Yungman wrote:
gh0st3g wrote:
Hello guys,
I woukd like some help from you.
I am goung to build one, but there is something about capacitor on power supply.
Should i place 330,000 uf insteed of 220,000 uf.
Follow the schematic firt capacitor 220,000 uf then registor then two 220,000 uf. Now i am going use 330,000 uf then registor and one 330,000 uf.
Could it be like this?
Thanks for all your help.
Regards,


You mean the schematic use 22,000uF, then a resistor, then TWO 22,000uF in parallel?

Unless you have a good reason, I would stay with two 22,000uF in parallel.

the reason is two smaller value cap in parallel is usually ( say always) better than one single big cap. The bigger the cap, the higher the ESR and ESL. Two smaller cap in parallel with lower the ESR and ESL by half.

I design my amps using over 10 of the 10,000uF in PARALLEL to get the very low ESR and ESL. Hiraga is a high quality amp, I would not mug with this.


Hi and Thank you,
I am not meaning like this. I upload the schematic with my idea.
After modify like this the capacitor value still 1.2F
Thank you again.

Author:  Yungman [ 03 Jun 2018, 15:17 ]
Post subject:  Re: Question of the amplifier circuit Jean Hiraga's Class-A

Hi

Is this on a pcb or you are just wiring it up? PCB make it more rigid to changes. If it is just wiring, then you have a lot more option.

It is more important to have more capacitance AFTER the 0.5ohm resistors. My first post still stand, it is better to have more lower value caps in parallel to lower the ESR and ESL. I would not use such a huge cap. Even 220,000uF is very big and expensive. I would either stay with what is on the schematic or even use smaller caps.

As I said before, I use a lot of 10,000uF caps in parallel to make up 2F of total capacitance in my amps. It's cheaper as it's not screw top. I use snap in, but I make a pcb for that. It's a lot cheaper AND it works a whole lot better.

So it depends on how much DIY you are willing to do to wire the caps, the more the lower value caps in parallel, the better. Hope that helps.

Author:  Yungman [ 03 Jun 2018, 20:38 ]
Post subject:  Re: Question of the amplifier circuit Jean Hiraga's Class-A

I was just looking at the Hirage schematic ( same as the one in the first post here)

I really don't think you need that high value capacitance. The important thing is the front end stage, but Hiraga design really doesn't matter that much. If I were to do anything, I would add a 220uF like this:

Attachment:
Hiraga.JPG


But I don't even know it's that important as the first stage is only an emitter follower.

Let's be real, Hiraga is a well known design......BUT, it's NOT the real high end design. It ONLY has single output transistor pair. There is a lot of disadvantage with only one pair. There is a very good reason why the high end amps has over 8 pairs of output transistor, it's not for show, but with very solid theory behind it. I don't think it's worth paying a few hundred dollars on the filtering caps. You don't want to spend a few times the worth of the amp just on filter caps.

I really think you should just use about 33,000uF per side and listen to it to see. This is not black magic, all the cap is just to reduce the saw tooth ripple on the supply line, nothing more. No matter how much capacitance you put, there will be ripple..................

Bottom line, just build it and listen first. If you really want high end, there are better circuit that worth putting in more money. I would just use more smaller value caps in parallel and call it a day for a whole lot cheaper.


And let's put it in another way. If that little ripple is so important, I would use two 24V SMPS to power the whole thing, it would be a lot cheaper. I use SMPS from ebay ( about $25 each of the 24V 400W SMPS) to power up my first run amp and I got really good THD figure ( in 0.005% range). It worked. The only thing that stop me from using SMPS is I can't get about 36V supply cheap enough. Last thing I would do is to spend over $100 for each of those big caps.

Author:  gh0st3g [ 05 Jun 2018, 06:56 ]
Post subject:  Re: Question of the amplifier circuit Jean Hiraga's Class-A

Yungman wrote:
Hi

Is this on a pcb or you are just wiring it up? PCB make it more rigid to changes. If it is just wiring, then you have a lot more option.

It is more important to have more capacitance AFTER the 0.5ohm resistors. My first post still stand, it is better to have more lower value caps in parallel to lower the ESR and ESL. I would not use such a huge cap. Even 220,000uF is very big and expensive. I would either stay with what is on the schematic or even use smaller caps.

As I said before, I use a lot of 10,000uF caps in parallel to make up 2F of total capacitance in my amps. It's cheaper as it's not screw top. I use snap in, but I make a pcb for that. It's a lot cheaper AND it works a whole lot better.

So it depends on how much DIY you are willing to do to wire the caps, the more the lower value caps in parallel, the better. Hope that helps.

Hi yungman,
Thank you,
I still follow the original schematic, just replace capacitor, as the schematic that i highlight, is there any schematic that using 4 capacitor value 330,000uf instead of 6 capacitor 220,000uF.
If i am using parallel capacitor for reach 1.2F then I have to pay expensive than buying 220,000uF.
Regards,

Author:  szybkijanek [ 15 Feb 2019, 17:11 ]
Post subject:  Re: Question of the amplifier circuit Jean Hiraga's Class-A

Youngman, i'm very interested your latest answer, can U show me best schematic with SE transistor amp?

Author:  ILoveHiFi [ 17 Feb 2019, 01:36 ]
Post subject:  Re: Question of the amplifier circuit Jean Hiraga's Class-A

24v 4 amp SMPS from aliexpress is like about $15-20usd total to your house shipping included

Author:  szybkijanek [ 18 Feb 2019, 05:04 ]
Post subject:  Re: Question of the amplifier circuit Jean Hiraga's Class-A

Transistor ampLIFIER of course

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