type 1185, extremely rare

Date code K1 and L1

Bottom D getter

TV-7D/U tested at 46,46 and 56,52

by using the settings for 6SN7 and

adjusted the minimum good value to 39 from 50 by applying a ratio of gm of ECC32 to 6SN7

So the tubes were tested good to strong

Further tests performed with plate voltage 100V and grid bias at 1.84 (by a LED connected at cathode)

currents were measured as followed:

Tube ECC32 L1, Ia = 2.06mA and 2.32mA

Tube ECC32 K1, Ia = 2.01mA and 2.13mA

where tube curves show that the current is around 2.1mA.

Therefore the static measurment of the tubes conformed to specifications.

By applying a 1V p-p signal to the grids, and then measured the AC current at cathodes,

the gm values were obtained:

Tube L1, gm = 1.53mA/V and 1.62mA/V

Tube K1, gm = 1.42mA/V and 1.47mA/V

These were also consistent with observations on the tube curves.

See pictures of the test setup.

Sound tests with the tubes inserted to a Sun Audio SV-KT88 were excellent.

With these test results, I have full confidence that the tubes will perform excellently.