Klausmobile Tube Tester Files
Reflector (Saratov), 12/1975. I have a treasure chest - four nearly identical 45Pi's from one production batch. How they packed 8W plate power in a mini package is a mystery, but look at the plate - it's more than 1 mm thick metal!
| Standard specifications per each triode | |||
| Parameter | Maximum | Operating Point | Measured ** |
| Ua, V | 150 | 150 | 140 |
| Ug, V | - | (-1.2) | -1.2 |
| Ia, mA | 52 | 40 | 33 |
| Pa, W | 7.8 | (6.0) | (5.2) |
| Gm, mA/V | - | 45 | 38 |
| Rp, kOhm | - | 1.2 | 1.1 |
| Mu, V/V | - | 52 | 42 |
** The operating point is on the edge of my gear. I shifted a bit down to get reliable readings.
The tube was a nightmare to test. It oscillated above 15mA current (at negative Ug) - despite ferrite chokes everywhere. Note that it has 2 grid leads and 4 cathode leads. I hadn't had a clue what to do with it until I looked back at specs - they require maximum gris leak resistance of 150kOhm or less. I started loading 300k resistors across grid-cathode... it took 6 (R=50kOhm) to quiet down ringing. Unfortunately, this leakage path in grid chain was not within grid amplifier loop, so the actual Ug values are 10% less than those indicated on plate curves. This also means the Gm/Mu/Rp numbers need to be re-adjusted for this Ug error, so there's no Gm/Mu tables.
Full power curve. Oddities at extreme power are caused by weak power supply, disregard them. Also disregard the color coding - this is an effect of grid leak path. Useful grid voltage is up to +0.5? before significant currents.
32mA closeup. Remember, the Ug labels must be decreased 10%.
Legend: White curves: Ig<5uA Yellow: 5<Ig<20uA Red: 20<Ig<300uA. Measurements terminate at Ig>300uA
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