All fet super buffer

[Pasul]

Hi all,
I have problem with this construction:
http://www.borbelyaudio.com/pics/EB-602-403 final.pdf

Buffer working good,but DC stability isn´t very well!When I switch on at out is 240mV and going down to 0V.After two minute stable on 3-25mV.Still going up and down.I did two this buffer ,and doing this both of them.

excuse my english,

regards,

 

[Upupa Epops]

Help is easy : 'cos EB like to listen DC signal , all his connections are DC coupled...If you make feedback loop not as " DC " and connect R 7 through some larger capacitor ( elyt + foil in parallel ), problems will be away....Second solution is to get this buffer into thermoisolated box with regulated constant temperature...

 

[Pasul]

Hi Mr.PD,
when I construct All fet line amp ,there is not problem with DC.But there is DC servo.In super buffer I make feedback loop.Gain 6dB.I put this Buffer in TopDAC.

I go try to put there capacitor.

Thanks for help

P.S.Second help looks fine!

 

[lineup]

i think you will get better dc-stability

 

[john curl]

Servo would be better.

 

[MINER]

Does anyone has schematics for this preamp???