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Old 10th July 2012, 04:59 PM   #831
Zen Mod is offline Zen Mod  Serbia
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Old 10th July 2012, 05:25 PM   #832
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I guess properimplementation entails trimming the distortion using P3 to minimum. By adding CS like in Leaving Class A article, you get some of that firstwatt sweetness back in form of second harmonics, but still benefit from lower overall distortion.
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Old 12th July 2012, 08:51 AM   #833
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I guess its built for 110v AC?Can it be used for 220v,I guess it is easy to use a f.e.x a 24v trafo?
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Last edited by Ryssen; 12th July 2012 at 08:54 AM.
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Old 13th July 2012, 03:09 AM   #834
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Quote:
Originally Posted by Ryssen View Post
I guess its built for 110v AC?Can it be used for 220v,I guess it is easy to use a f.e.x a 24v trafo?
It can be used in countries with 100V, 110V, 220V, 240V etc without the need to use any trafo. There are some good info in the build guide also.

Thanks
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Old 13th July 2012, 08:25 AM   #835
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Quote:
Originally Posted by Botte View Post
Has anyone tried adding a current source to one side of the follower output, Nelson talks about this in the "Leaving Class A" article? I'm thinking about giving this a try and wonder if anyone has any experience with it.

Thanks,
Hi Botte,
No I haven't butt If you do give it a try I would like to hear your results,
and if probability prevails ..papa said it will work,lol, I am going to to read that article and see how it works! GOOD LUCK!
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Old 15th July 2012, 06:01 PM   #836
nkdk is offline nkdk  Denmark
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Hi
I got a little trouble with biasing the ba3, i use thosiba fets.
Q1= 2sk170
Q2=sj74
Q3=2sj313
Q4=2sk2013
Dc. rails 25.2 Vdc Dc volts over r10-r11 max 0,4 Vdc.
everything is after the bom. so what is wrong?
Nkdk
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Old 19th July 2012, 10:22 PM   #837
tinitus is offline tinitus  Europe
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Quote:
Originally Posted by nkdk View Post
I got a little trouble with biasing the ba3

Dc volts over r10-r11 max 0,4 Vdc.
BA3 frontend schematic says 1V

wrong value on bias pot
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Old 20th July 2012, 01:59 AM   #838
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Quote:
Originally Posted by nkdk View Post
Hi
I got a little trouble with biasing the ba3, i use thosiba fets.
Q1= 2sk170
Q2=sj74
Q3=2sj313
Q4=2sk2013
Dc. rails 25.2 Vdc Dc volts over r10-r11 max 0,4 Vdc.
everything is after the bom. so what is wrong?
Nkdk
There are variations in parts that you have to account for. It was talked about that you might have to increase variable resistor P1 P2 in order to get the voltage up to turn on Q3,Q4 if their Vgs is higher than normal. The other way is to choose a higher Idss for the input devices.
What's the voltage across the 600 Ohm drain resistance, assuming you have adjusted for maximum.
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Old 20th July 2012, 08:02 AM   #839
tinitus is offline tinitus  Europe
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Quote:
Originally Posted by BDP View Post
.......you might have to increase variable resistor P1 P2........
with higher value bias pot, which 'side' is increased ?
supply side, or jfet side ?
reason I ask, you could try with a series resistor

but by using a slightly too big bias pot, it should be easy to lower its value with paralel resistor
btw, why isnt there any this time ?
isnt there usually one ?
for whatever reason
the above, or in case the pot fails ?
maybe it also takes some of the 'load' off the pot, but I dont know
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Old 20th July 2012, 05:10 PM   #840
nkdk is offline nkdk  Denmark
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Hi
Thx for the answers
I have swap p1-p2 too 1kΩ and the volts over R10-11 is 1,0 volts now, then this okay ,
there is running 45 ma , but how about Q1-2 there is only running 4 ma,is that a problem ??
600 Ω drain resistor? , there is no 600 Ω resistor only 10 Ω with a 100 Ω pot
Nkdk
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