pin numbers European 7 pin (c)

hello all

I am building a valve tester and run into a small problem. I need to number alle pins of the sockets in order to switch the correct connecion to that pin. But for the European 7 pin socket (AK1, ACH1, I find numbering CCW counting from the cathode pin. But when I compare with the X22 with the same socket, the pins numbering starts at the same pin as the british 7 pin socket, but counting CW.

I think that this base is originally a Phillips base (C), so I tend to adopt the AK1 counting.

Please advise

Kind regards

Nico

• tube tester (116 KB)

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Hello Nico,

this drawing shows the arrangement of the Philips C35 base, shown from below (Unteransicht).
Hope this helps.

Best Regards, Jacob

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Thank you very much Jacob, problem solved. Now I can wire the last socket.

Kind regards

nico

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For high mu valves it is possible that they might oscillate due to long wiring and capacitance. If this problem occurs, damping ferrrite perls with the wiring may help.

Regards,

Dietmar

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Thanks for the advice Dietmar, highly appreciated.

I have at every switch MC a 100 Ohms in series with a 4700 pF capacitor in order to suppress oscillations. Also at the top connection a coil with resistor suppressor has been added. 

If I still have oscillations, I will add ferrite supressors.

kind regards

nico

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The tube tester is about finished and works very nice. By adding the damping using 100 Ohm is series with 4700 pF at the last socket in the cabling, all oscillation problems are solved.

I added a small circuit to directly measure S. by adding a block generator af approx 1 kHz and superpone 100 mV to the grid voltage. In the anode circuit I measured the AC voltage over 100 Ohm (low with respect to the anode impedance) using a 1 : 10 transformer tuned at the high impedance sec. to the generator frequency. The sec voltage is measured and rectified by a synchroneous detector circuit and displayed at a small digital voltmeter from Aliexpress. The result is a nicely stable display of S in mA/V.

The value displayed has been verified by measuring the Anode current variation with 1 volt of -Ug variation and is correct over the full range covered by the tube tester (max 450 Volt Ua at 120 mA or approx 60 Watts)

If there is interest in the circuit, I will publish

Kind regards

to all

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