![Image](http://www.intactaudio.com/forum/files/img_0858_199.jpg)
the long narrow window and dual bobbins makes for a very low capacitance design. The tape appears to be around 4mil or in the M2 neighborhood.
They measure really well and should make wonderful plate chokes.
DCR is around 320 ohms.
L v. I
![Image](http://www.intactaudio.com/forum/files/screen_shot_2010_05_21_at_44410_pm_880.png)
I'd be comfortable with 15-20ma...
L vs. AC@50hz (10madc)
![Image](http://www.intactaudio.com/forum/files/screen_shot_2010_05_21_at_44619_pm_515.png)
the lower inductance at low excitation is typical of steel.
Now for the HF response and again it looks good.
![Image](http://www.intactaudio.com/forum/files/screen_shot_2010_05_21_at_44653_pm_143.png)
looks like a winner with any tube under say a 4K rP and 20ma of current.