Pumpkin preamp - ordered by Steen , official making thread

[Zen Mod]

Hi Tony

easy peasy , for 2SJ109, matching by Idss :

source and gate to +9 (max 12V)

drain to mA meter red probe

mA meter black probe to gnd

[tonimxp]

Originally Posted by Zen Mod

Hi Tony

easy peasy , for 2SJ109, matching by Idss :

source and gate to +9 (max 12V)

drain to mA meter red probe

mA meter black probe to gnd

Hi Alex i have just tried and the results with 9v power voltage are this :

1° 2sj109 91/92 mA

2° 2sj109 53,5/53,5 mA

Please what do you think about different idss betwen 1° and 2° jfet?

I also have four 2sj74 bl 6g and i tried with same idss matching method.
the results are this:

1° 2sj74 10,10mA
2° 2sj74 10,10mA
3° 2sj74 10,04mA
4° 2sj74 10,07mA

Please can you advise me what to use for your Aleph J Babbelfish?

Thanks in advance

[Zen Mod]

they're fakes

according to 2SJ109 datasheet , there are 3 groups of Idss for exactly same test setup :

GR , BL , and V

if you made test as I wrote ( see enclosed sketch) , they're fakes without doubts

look at 2Sj74 side , presume that Rs is zero , for your case of measuring (full) Idss

http://jm.plantefeve.pagesperso-orange.fr/2SJ109.pdf

[tonimxp]

Originally Posted by Zen Mod

they're fakes

according to 2SJ109 datasheet , there are 3 groups of Idss for exactly same test setup :

GR , BL , and V

if you made test as I wrote ( see enclosed sketch) , they're fakes without doubts

look at 2Sj74 side , presume that Rs is zero , for your case of measuring (full) Idss

http://jm.plantefeve.pagesperso-orange.fr/2SJ109.pdf

Yes my Rs is zero and my type are BL ,so...what should be the correct IDSS (if they were genuine) in my case, with 9V and without Rs?

[Zen Mod]

see picture above

6 to 12mA

[tonimxp]

Originally Posted by Zen Mod

see picture above

6 to 12mA

I have to open a dispute on ebay, please with what voltage value (with my set up measurement) should get from -6 mA to-12mA Idss?

[Zen Mod]

as I said already - in range of 9 to 12V

what you got are probably re-labelled bjt's

[tonimxp]

Originally Posted by Zen Mod

as I said already - in range of 9 to 12V

what you got are probably re-labelled bjt's

thanks Alex

[tonimxp]

So...about my four 2sj74 bl 6g

1° 2sj74 10,10mA
2° 2sj74 10,10mA
3° 2sj74 10,04mA
4° 2sj74 10,07mA

Are they ok to use for your Aleph J Babbelfish?

And about my post n°3420 of this tread what do you think?

For 2sj310 (Q1 and Q2) of Pumpkin i have found those values of Vgs:

180-184-(187-188)-(193-196) mV so i have match as in parenthesis.
The current draw is set to 5mA for five minutes test time.

I have to ask you your comments for results.




Thanks in advance

[Zen Mod]

Originally Posted by tonimxp

So...about my four 2sj74 bl 6g

1° 2sj74 10,10mA
2° 2sj74 10,10mA
3° 2sj74 10,04mA
4° 2sj74 10,07mA

Are they ok to use for your Aleph J Babbelfish?

perfect

just take care of pinout

Originally Posted by tonimxp

......
And about my post n°3420 of this tread what do you think?

For 2sj310 (Q1 and Q2) of Pumpkin i have found those values of Vgs:

180-184-(187-188)-(193-196) mV so i have match as in parenthesis.
The current draw is set to 5mA for five minutes test time.

I have to ask you your comments for results.




Thanks in advance

they're good , of course

attached pic - view from top (as a bird ....... or Batman )