- CT1-BOX is designed by Douk Audio, in order to measure the cathode current of the power tube for bias reading (at low voltage side of the tubes), suitable for EL34, KT88, 6L6, 6V6, 5881, 6550, KT66, KT100, KT120, 7027 etc., equipped with large current meter, easily and distinctly to read.
- Ceramic socket and gold pins for longer service life, tough gold pins with a thick gold plating.
- Dual larger current meter reader, max test current range up to 100mA.
- Adopting copper wire to ensure excellent conductivity.
- Each probe tester is soldered by outstanding craftmanship.
- Metal case, more solid and with better shielding performance.
- Brand: Douk Audio
- Model: CT1-BOX
- DC Plug: 5.5/2.2 mm
- Length of tube socket cable: 23cm
- Material of tube socket: ceramic
- Range of current meter: 100mA
- Dimensions of box (W*D*H): 150*106*70mm / 5.90*4.17*2.75in
- Net weight: 500g / 1.10lb
- Package weight: 1000g / 2.20lb
- Probe Tester ×1 Pair
- Current Meter Box ×1
User Manual of Douk Audio CT1-BOX
How to use it ?
- Turn off your amplifier, and connect two probe testers separately to the A and B interface of CT1-BOX.
- Remove the power tubes, insert them into the bias probe sockets.
- Insert bias meter probes into the tube sockets of the amplifier.
- Turn on your power amp, let the tubes get warm about 5 minutes, then read the bias measurement.
- The left current meter is reading "A" input, and the right current meter is reading for "B" input. If the reading value of both are the same, that's perfect. If not , the difference should be no more than 2mA or 3mA for a good balance between the tubes.

Versatile Compatibility
- Designed for a wide range of power tubes including EL34, KT88, 6L6, and more, ensuring precise bias current measurement.

Optimized Performance
- Copper wiring for superior conductivity and a metal case for enhanced shielding, ensuring reliable and interference-free measurements.

High-Precision Readings
- Dual current meter reader with a 100mA range allows for accurate bias adjustments and easy readings.

Durable Construction
- Features ceramic sockets with thick gold-plated pins for long-lasting use and reliable connections.