Products


The Tube IMP mini TT

Information from owners manual subject to change with out notice.

The Tube IMP mini TT is designed to measure the steady state current, gain and transconductance characteristics of B9A double triodes with the standard ECC83 / ECC88 footprint

Controls and indicators

Test selector

The test selector selects between:
  1. Cathode current, this is a direct reading of the DC cathode (and anode) current passing through the section of the valve under test in mA.
  2. Transconductance. In this test an AC signal is fed to the grid, and the resultant AC current at the cathode is amplified and rectified to give a reading. Transconductance is the change in cathode current in mA divided by the change in grid voltage in volts (mA/V).
  3. Gain. For this test the HT supply is switched in to high impedance current source mode, with an impedance of about 2Mohms. An AC signal is fed to the grid and the resultant AC anode voltage is then attenuated and rectified to give a reading. As the HT supply is not a perfect infinite impedance current source, valves with a higher anode impedance will appear to have less gain.

Grid voltage adjuster

This knob adjusts the grid voltage between 0 and -10 volts, allowing the current flowing through the valve to be adjusted.

HT adjuster

This knob adjusts the HT voltage between 0 and 200 volts.

Section selector switch

This switch selects which half of the valve is to be tested.

Heater voltage selector

The valve tester connects the heater voltage to pins 4 and 5 of the B9A socket. To test series and parallel heater filament type valves, this switch adjusts the voltage between 6 and 12 volts AC.

LCD display

This display directly indicates the reading of the measurement being taken in the appropriate units for the test (mA, mA/V, and gain).

HT over current indicator

This LED lights to indicate that the HT supply has gone in to current limit, typically >12mA. Readings made in current limit will be inaccurate because the HT voltage will not be as indicated on the HT setting dial .

Specs

    HT voltage max 200 volts
    HT adjustment 0 to 200 volts *
    HT setting accuracy typically better than +-2% of full scale
    HT current 10mA max *
* Voltage headroom is reduced at higher currents. i.e. 200v between 0 to 5 mA, and then reducing to 150volts at 10mA.
Note: The power supply is not powerful enough to do all data sheet tests.
    HT impedance on GAIN setting > 200Kohm at 100v
    GRID voltage range 0 to -10 volts
    GRID voltage setting accuracy typically better than +-2% of full scale
    Heater voltage 6.3 12.6 volts DC, switchable
    Heater current 350mA, 500mA for less than 5 minutes

Measurement accuracy

    Cathode current 2%
    Transconductance 4%
    Gain +0 -5%

Equipment ratings

    Supply voltage 12 volts AC +20% - 0% *
    Supply frequency 47 to 63 Hz
    Input current 1A **
The units power input is protected by a resettable fuse.
    Power input connector coaxial 2.1 mm power connector
    Valve base Ceramic B9A
Operating environment: 5 to 35oC, 5 to 90 % humidity? 0 to 2000M altitude
* The supplied "wall wart" power supply output voltage is load dependent
** This is ultimately dependent on the heater current of the valve being tested and the HT current.

Specification subject to change without notice

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last updated Sun Apr 22 20:35:06 BST 2007