Paradise Builders

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Joined 2005
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No, the trimmers will be adjusted once everything is in and settled, check the assembly guide there is lots of details there.
Please make sure you adjust BEFORE you hook up a cartridge and amplifiers - missing adjustment of the input offset can lead to a large output DC offset, and if the rest of your chain is DC coupled this can have interesting side effects particularly on your speakers ;-(
 
MATCHING Question

hi, a question about matching
SK170
J113
J310

i would go with a 9 volt batterie (no powersupply in the house) and a DC voltmeter. Connect the +V to the Drain, connect the Gate and Source together to a 100 ohm resistor, and connect the other lead of the resistor to ground.

i measure the voltage across the resistor, which gives the Idss.
1 volt = 10 mA of current.

1) is this correct?
2) i can use this matching situation for all those 3 N-Fets, right?
3) is it normal to get around 3V with the J310?
4) what values would be perfect working with
SK170
J113
J310

THANK YOU VERY MUCH!!!!!
 
hi, a question about matching
SK170
J113
J310

i would go with a 9 volt batterie (no powersupply in the house) and a DC voltmeter. Connect the +V to the Drain, connect the Gate and Source together to a 100 ohm resistor, and connect the other lead of the resistor to ground.

i measure the voltage across the resistor, which gives the Idss.
1 volt = 10 mA of current.

1) is this correct?
2) i can use this matching situation for all those 3 N-Fets, right?
3) is it normal to get around 3V with the J310?
4) what values would be perfect working with
SK170
J113
J310

THANK YOU VERY MUCH!!!!!

Hi miepa
So is it right for your JFet,s :)

http://origin.dastatic.com/forums/gallery/data/500/JFET_Bias_point_IDSS.JPG
http://origin.dastatic.com/forums/gallery/data/500/JFET_Bias_point_VSG.JPG

Take care
Werner
 
and what is the appropriate value to use in the paradise?

SK170 - idss 6.6-6.9mA
J113 - VGS 2.2 ?
J310 - VGS 3.2 ?

and is it a problem if i use on one board two J113 with VGS 2.2 and on the other board two J113 with VGS 1.9 ?


I don.t know is the my answer. I have balanced only BC 327 , BC337 and
the Calvin Buffer Transen.
I have checked, because I had in early times problems, the 2SK170
and they have in my build Idss 8,5mA.
My paradise sounds super fantastic in my last set up. :D
Tahe it easy
Werner
 
if you use a 9V battery and drop 3V across the measuring resistor then the Vds is ~6V.
Idss is the current when Vds=10V for most datasheets.
As you reduce the Vds the Id will change and with some devices it will change a lot.
Use a 10r measuring resistor to get closer to your 10Vds and use an adjustable regulated power supply and adjust the output so that 10Vds is maintained during measurement.
Note also that Tj=25degC for Idss. If you cannot maintain that 25degC then you have not measured Idss.
The best you can do is try to compare different devices and try to maintain constant P in the device during comparison.