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Old 23rd December 2011, 11:01 AM   #11
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OnAudio, why a new thread for this amp ??

You should show THD and FFT s at higher powers than 1 watt, then things dont look so rosy anymore. Show a 10 or 20 volt swing so members can better compare to other designs on the forum.
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Old 28th December 2011, 03:37 AM   #12
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Quote:
Originally Posted by Nico Ras View Post
Why? the device is rated at 150 degrees centigrade, it would be silly if they rated the diodes at any less.
Hi Nico,

Thanks about the heat. Apologies for that meant wattage. Could they handle say 4 watts ?

kind regards,

Harrison.
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Old 28th December 2011, 03:55 AM   #13
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Hi Nico,

Quote:
Originally Posted by Nico Ras View Post
Why use a Vbe multiplier with Lateral Mosfets, that whole arrangement including precision pots can be replaced by a single resistor.
That could work. However I prefer this setup or a zener or string of diodes and it has noting to do with heat tracking


Quote:
Originally Posted by Nico Ras View Post
What are the purpose of D9 & D10, the double diode Vdrop will remain the same regardless of the additional noise introduced by the zener.
There is a thread in this forums that could explain that. I have lost track of it. With rail modulation the current isn't firmly held, thus the applied measures. The Goldmund clone features one of the sinks discussed there.

kind regards,

Harrison.
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Old 28th December 2011, 03:59 AM   #14
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Quote:
Originally Posted by dadod View Post
OK show us +- swing, or you don't know how to do that?

dado
Hi Dadod,

Could you show me
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Old 28th December 2011, 04:16 AM   #15
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Hi Homemodder,

Quote:
Originally Posted by homemodder View Post
OnAudio, why a new thread for this amp ??
This amplifier isnt the one you think it is. With those FETs on the output, lets say its a different animal.
Quote:
Originally Posted by homemodder View Post
You should show THD and FFT s at higher powers than 1 watt, then things dont look so rosy anymore. Show a 10 or 20 volt swing so members can better compare to other designs on the forum.
The first watt is the most important . Exactly what do our ears perceive ?

kind regards,

Harrison.
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Old 28th December 2011, 06:10 AM   #16
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Quote:
Originally Posted by OnAudio View Post
Hi Nico,


That could work. However I prefer this setup or a zener or string of diodes and it has noting to do with heat tracking




There is a thread in this forums that could explain that. I have lost track of it. With rail modulation the current isn't firmly held, thus the applied measures. The Goldmund clone features one of the sinks discussed there.

kind regards,

Harrison.
Very likely it will not be held by a zener either. So your reasoning is hearsay?
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Kindest regards
Nico
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Old 28th December 2011, 03:04 PM   #17
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Quote:
Originally Posted by Nico Ras View Post
Very likely it will not be held by a zener either. So your reasoning is hearsay?
Hi Nico,

Really ?

How it works is that we take the first voltage. This voltage will have some variation, then we take a fraction of that variation by using a voltage divider. Resulting in better regulation.

How would you go about it ?

Kind regards,

Happy new year, hope your having a great time

Harrison.
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Old 19th January 2012, 01:56 PM   #18
RSK is offline RSK  Malaysia
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Default SYMFET - pcb first try

Hi Harrison,
I am not very good at pcb layout.
But at least I try to make the best I could. Q2 and Q17 has its individual heatsink. Output mosfets are mount under pcb.
Please commend any improvement.

Kind regards,
Raj
Attached Files
File Type: pdf SYMFET.pdf (44.3 KB, 60 views)
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Old 19th January 2012, 07:54 PM   #19
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Hi Raj,

Nice Job. I took a quick peek. I saw two pairs of mosfets instead of three. I found the ground slightly thin. The feedback looks ok to me since you took it from a stub.

I hope PCB domain experts will give their insights.

kind regards,

Harrison.
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Old 20th January 2012, 02:17 AM   #20
RSK is offline RSK  Malaysia
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Quote:
Originally Posted by OnAudio View Post
Hi Raj,

Nice Job. I took a quick peek. I saw two pairs of mosfets instead of three. I found the ground slightly thin. The feedback looks ok to me since you took it from a stub.

I hope PCB domain experts will give their insights.

kind regards,

Harrison.
Hi Harrison,
Can it work with two pairs of mosfet? What maximum rail voltage to use?
I will alter the thin tracks accordingly.

Regards.
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