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- 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.
Customer Reviews
Did the job, no issues. Easy to use.
This item arrived well packed, there was a small dent on an edge of box, but interior foam being fairly thick no harm done. I’m very happy with the analog meters as opposed to a digital readout. It’s good to be able to observe both sides of a typical output circuit simultaneously.Previously I had purchased a “no name” digital bias meter rig that had two sockets, one readout and a switch. WhenI opened up the el-cheepo housing, and traced the circuitry, I find that the meter was actually connecting just one tube cathode circuit at a time, leaving the other tube cathode floating! This setup was nearly twice the price of this unit. So much for my assumption the digital bias meter was just reading voltage drop across a 1 ohm resistor, and both cathode circuits were active.Current measurements agree closely to a Fluke DMM, so I’m confident with that. I’ve read elsewhere the supplied sockets are fragile, my experience so far is to be cautious.So far I’m satisfied with this unit, and the price.
Be very careful when aligning with pins and sockets. You can very easily misalign and cause damage to meter and tubes. Slightly smaller alignment pin will allow you to not get correctly aligned with sockets and tubes. I blew up one meter and red-plated a tube.Cannot find a replacement meter since meter does not have full scale parameters on face.
So easy to set up bias on mt 64 custom deluxe put the probe on first then tubes turn on amp and it reads both tubes. Took me about 5 mins after warm up to complete the bias.
It worked well the one time I have used it. The tube socket included with the bias tester is stiff and difficult to get into the tube socket on the amp chassis. Even though I thought I was gentle, the pin orienting the bias tested plug broke off on removal from the chassis, I imagine the tester will still work but I will have to be careful with orienting the plug since there is no alignment pin. Picture above. My biggest complaint is that although Amazon and Douk say there is an 18 month warranty, it is impossible to submit a product complaint with Douk because their automated assistant sends you to Amazon woho tells you that it is not returnable and talk to Douk! I just want them to replace the plug. I would otherwise recommend this device with the comment that it seems flimsy for a premium price.
