B1 with no in/out capacitors..

Chul · 17th March 2009, 10:41 AM

Hi,

Am I doing something wrong here?

It works just OK and with random unmatched JFets, I read 0.09VDC at the output. I think I can decrease this number one way or another, maybe with matched JFets?

I'm a novice DIYer, any comment is appreciated.
BTW what maximum voltage swing can B1 accept?

Cheers,
Chul

Zen Mod · 17th March 2009, 11:45 AM

Quote:

Originally posted by Chul
Hi,

Am I doing something wrong here?

It works just OK and with random unmatched JFets, I read 0.09VDC at the output. I think I can decrease this number one way or another, maybe with matched JFets?

I'm a novice DIYer, any comment is appreciated.
BTW what maximum voltage swing can B1 accept?

Cheers,
Chul

put trimmer pot between jfets , and take output from wiper

let them cook for a while , then adjust exact 0 at output

use 47R trimmer pot

max swing ........ say - enough ........

( at least overall PSU voltage , decreased by ..... say ........ 3 V )

Chul · 17th March 2009, 12:43 PM

Just 50ohm pot. Thank you for the tip

I am planning to use this B1 in the linestage using old vacuum tube that suffers from high Rp and Zout. This way I don't even leave the 0.09V which affect little in the tube circuit.

But 3V swing may not enough...Should I use increase the voltage to 12V?

Chul

EUVL · 17th March 2009, 05:08 PM

See also :

http://www.borbelyaudio.com/adobe/ae699bor.pdf

http://www.analogzone.com/col_01302004.pdf

Some other Source Follower COnfigurations

Patrick

Zen Mod · 17th March 2009, 05:11 PM

Quote:

Originally posted by Chul
.....

But 3V swing may not enough...Should I use increase the voltage to 12V?

Chul

I meant PSUvoltage - few volts ;

Chul · 17th March 2009, 10:11 PM

Hi Patrick,

Thank you for the links. At least I now know I did not do something harmfull to my audio..

Cheers,
Chul

EUVL · 18th March 2009, 01:31 AM

Take a look at my version of the "B1" :

B1-Turbo on a Chip

Patrick

Nelson Pass · 18th March 2009, 09:12 PM

Quote:

Originally posted by Chul
It works just OK and with random unmatched JFets, I read 0.09VDC at the output. I think I can decrease this number one way or another, maybe with matched JFets?

You could use Q101 with a higher Idss than Q100 and place a
50 ohm pot on the Source to Ground of Q101. This would allow
you to set the current of Q100 at its Idss value which will give 0V
offset.

Chul · 23rd March 2009, 05:59 AM

It's nice to hear from the one and only..

I'm the guy who sent AER driver the other day..

Cheers

Nelson Pass · 23rd March 2009, 09:20 PM

How are you doing with those AER's?

17th March 2009, 12:43 PM	#3
Chul diyAudio Member Join Date: May 2003 Location: Pusan Korea	Hey, that simple? Just 50ohm pot. Thank you for the tip I am planning to use this B1 in the linestage using old vacuum tube that suffers from high Rp and Zout. This way I don't even leave the 0.09V which affect little in the tube circuit. But 3V swing may not enough...Should I use increase the voltage to 12V? Chul __________________

17th March 2009, 10:11 PM	#6
Chul diyAudio Member Join Date: May 2003 Location: Pusan Korea	Hi Patrick, Thank you for the links. At least I now know I did not do something harmfull to my audio.. Cheers, Chul __________________

23rd March 2009, 05:59 AM	#9
Chul diyAudio Member Join Date: May 2003 Location: Pusan Korea	Thank you Papa.. It's nice to hear from the one and only.. I'm the guy who sent AER driver the other day.. Cheers __________________

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17th March 2009, 05:08 PM	#4
EUVL diyAudio Member Join Date: Oct 2003	See also : http://www.borbelyaudio.com/adobe/ae699bor.pdf http://www.analogzone.com/col_01302004.pdf Some other Source Follower COnfigurations Patrick

18th March 2009, 01:31 AM	#7
EUVL diyAudio Member Join Date: Oct 2003	Take a look at my version of the "B1" : B1-Turbo on a Chip Patrick

23rd March 2009, 09:20 PM	#10
Nelson Pass The one and only Join Date: Mar 2001	How are you doing with those AER's?

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