ECC88 - 6DJ8 Cascode Plate Curves

[dsavitsk]

Does anyone have plate curves for the ECC88/6DJ8 in Cascode? Lots of mentions of doing this, but I can't seem to put my hands on the data.

[payitforwardeddie]

This any good? ECC88 @ The National Valve Museum

[revintage]

Did this manually in my AVO maybe 20 years ago as I didn´t find the curves. Used Excel to get the curves. Can see if I still have them. If I remember it right I just used the Sg-voltage to bias the upper grid. Should be doable with any tubetester.

[DF96]

You can estimate from published curves.

Zeroth approximation:
Low triode works into a short circuit (vertical load line). Anode current merely goes through the upper triode - infinite Ra so curves are actually horizontal lines.

First approximation:
Low triode works into a load of 1/gm, so almost vertical load line. Upper triode sees lower triode as cathode degeneration resistor of Ra, so upper anode impedance is (mu+2)Ra. Curves are pentode-like.

Second approximation:
Remember that gm depends on current. This is when it gets messy.

[pmillett]

Not sure if it helps you any but the datasheets for some of my favorite "cheap alternates" have cascode curves... like the 6BK7 and 6BQ7:

http://www.mif.pg.gda.pl/homepages/f...93/6/6BK7B.pdf
http://www.mif.pg.gda.pl/homepages/f...93/6/6BQ7A.pdf

Pete

[dsavitsk]

Originally Posted by pmillett

Not sure if it helps you any but the datasheets for some of my favorite "cheap alternates" have cascode curves... like the 6BK7 and 6BQ7:

Great, that is helpful. Thanks.

[cerrem]

I remember having the cascode curves for this tube somewhere...
I also remember the data sheets was written in Russian...so if you search the Russian tube makers website you might get lucky....

cerrem

[Merlinb]

ECC88 cascode curves with 50V on the upper grid.

[ruffrecords]

Is this what you need?

http://www.ianbell.ukfsn.org/pics/e88cc-phillips.pdf

Last page but one.

Cheers

Ian