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Old 5th December 2012, 03:50 PM   #301
wahab is offline wahab  Algeria
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Quote:
Originally Posted by loek View Post
Hi Alex. I hope not to disturb you but i found a small mistake in your beautifull layout: the right side of D3 goes via R0 to E of Q20 but has to go to the base of Q7, this is not connected now.
Regards, Loek
Nice find , thank for the patience in examining the routing.
I guess that since Alex dont want to layout anymore , people
that are interested in using this PCB will have to correct themselves
the said track....

On another note , i d like to point a caracteristic of high NFB amps ,
that is , their output impedance that can be extremely low at low
frequencies and particularly at DC , no more than a few micro ohms
for the latter.

As such , an amplifier with about 2 micro ohm theorical output impedance at DC , as this one , will yield a high amplitude short circuit current if ever there is a significant output DC offset.

Assuming 10 mV DC offset and a short circuit made with a 2.5mm2 gauge wire
with 2 metres long path ( about 13 milliohm resistance), this will yield 0.77A DC output current , hence , even if an amp is not supposed to be output shorted to ground , care must be taken during build as even with no signal there s a risk if the output is shorted for a long time with eventualy higher DC offset .(a situation prevented in this amp thanks to a trimmer that is to be set such that the said offset is 1mV or less ).
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Old 6th December 2012, 02:57 AM   #302
wahab is offline wahab  Algeria
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Output impedance....
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File Type: gif HITACHI FFET MOD5.5 OUTPUT Z.gif (25.3 KB, 354 views)
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Old 6th December 2012, 03:26 AM   #303
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Hello
I only could do anything with the Alex layout if I or someone has ability to remove from Adobe.
One of the reason I must use my own PC board layout.
The situation is interesting, until Alex helped on us many people had opinion, thoughts (not necessarily bad think) but now many of those people just disappeared.
I thought someone who has access will take care about (some one will finish) that nice job Alex gave up.
I mean at least debug the layout or take further care about if necessary..
It would be a waste to leave such a nice and well designed layout like that...
Maybe some of us are overly sceptical about the amplifier performance, I don't know.
One think is sure, I'll produce the PC boards tomorrow or Friday, I go own and build it.
Thank you wahab one more time

Greetings Gabor
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Old 6th December 2012, 03:58 AM   #304
Junie is offline Junie  Philippines
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Quote:
Originally Posted by loek View Post
Hi Alex. I hope not to disturb you but i found a small mistake in your beautifull layout: the right side of D3 goes via R0 to E of Q20 but has to go to the base of Q7, this is not connected now.
Regards, Loek
Something like this?

Click the image to open in full size.
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Old 6th December 2012, 08:22 AM   #305
loek is offline loek  Netherlands
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Originally Posted by Junie View Post
Something like this?
Check connections of C12 please
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Old 6th December 2012, 10:31 AM   #306
AndrewT is offline AndrewT  Scotland
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Originally Posted by Junie View Post
Something like this?

Click the image to open in full size.
something like this?
I see nothing.
__________________
regards Andrew T.
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Old 6th December 2012, 04:13 PM   #307
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Quote:
Originally Posted by gaborbela View Post
Hello
I only could do anything with the Alex layout if I or someone has ability to remove from Adobe.
One of the reason I must use my own PC board layout.
The situation is interesting, . . .
Hello Gabor,

Have You ever check the E - mail I send to You many moons ago when You Start this nice new Fet - Amp thread ?

It is still there .... I Hope

Cheers
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Old 6th December 2012, 07:06 PM   #308
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Hello
No is not there. I check every day my E-mail, how I did today to...
May be it went into spam, usually I delete that with out reading.

Greetings Gabor
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Old 7th December 2012, 02:13 AM   #309
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Originally Posted by gaborbela View Post
Hello
No is not there. I check every day my E-mail, how I did today to... Greetings Gabor
Resented again ..

Cheers
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Old 8th December 2012, 01:48 PM   #310
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Project will be said in previous posts can be downloaded from here:
DW300 project - one HiFI Audio Amplifier that can run stable on 2 ohms
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