» » DUOKIT 3 - NEW DIGITAL ALL VACUUM TUBES, DIODES & VALVES TESTER - Very high plate voltage: 500v
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Full high performance digital tube tester kit, wired, adjusted & ready to use.


Full manual available here:



This kit is an evolution of the Duokit 2 of which it has all the characteristics but the plate voltage can go up to 500v against 450v for the Duokit 2.

This kit consists of a main card shown in photo 1 and a set of pre-wired peripheral elements + power sources, shown in photo 2.

Photo 4 is a view of the ready-to-use assembly.

Important: The heater power supply is not included in this kit because many users already have a suitable transformer. A regulated triple voltage power supply module (4v - 5v - 6.3V / 4A) is available on request.

The characteristics and performance are vastly superior to the whole traditional lampmeters and can measure a very wide range of tubes including valves, diodes and magic eye.

The display is shown in photo 3. It indicates the test parameters and the result in real time:

A: Plate voltage, adjustable from 2 to 500V +/- 5%

G2: Grid voltage 2 (screen), adjustable from 10 to 350V +/- 5%

G1: Grid voltage 1 (polarization), adjustable from 0 to -100V +/- 5% by 10-turn potentiometer

The plate current is displayed in 2 ranges in the lower right corner:

0 to 34mA, display on 2 digits + one decimal: XX, XmA

> 34mA, display on 3 digits: XXXmA

The maximum measurable current is 340mA for all types of tubes.

Complete documentation on request by giving me a valid e-mail address.

Summary of features:

Module: 130 mm x 110 mm maximum height 30mm

Backlit LCD display: 25 x 70 mm.

Single power supply: 110/230 V or on 12V battery via a converter
offered as an option.

Power from mains: 25W (35W max.) On mains and approximately 2A on 12V battery

Plate voltage: adjustable from 2 to 450 V

Screen voltage: adjustable from 10 V to 350 V

Grid 1 voltage: 0 to - 100 V (by 10-turn potentiometer)

Plate current range: 0 to 340 mA in 2 automatic sub-ranges: 0 to 34.0 mA (resolution 0.1mA) then 34 to 340 mA (resolution 1mA)

Neon short-circuit indicator in the plate.

Short-circuit protection: total

Overall accuracy: +/- 5% +/- 1 digit

Note: These values ​​are real, the use of a microprocessor allows a ultra fast measurement mode which minimizes power feed .


Few traditional lamp meters are capable of such measurements because they require heavy and bulky power supplies - the famous Metrix 310, for example, is limited to 100 mA of plate current.

The operation of the device is very simple: test parameters are adjusted, by means of 3 potentiometers, anode voltage, screen voltage (for tetrodes, penthodes, etc ...) and the bias voltage gate at the desired values ​​and, simultaneously, the plate currentcorresponding is displayed on the lcd screen.

The measurements are carried out at a rate of 2 per second which allows continuous reading parameters and result.

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Reviews about this DUOKIT 3 - NEW DIGITAL ALL VACUUM TUBES, DIODES & VALVES TESTER - Very high plate voltage: 500v (1 reviews)

- Review added the Sunday 18 June 2023 by Axel N
What a gerat product! I love the design of this kit.
It is very easy to work with and has, du... (Read more)
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The items will be delivered to the delivery address provided by the buyer during the order. Radioelec trusts La Poste to ensure quality and secure deliveries.

Upon receipt of payment, the sole proprietorship will dispatch the package to the buyer within the specified timeframe mentioned during the order (in-stock or on order products). Generally, La Poste's shipping time is 2 to 3 business days for deliveries within metropolitan France, in addition to the order processing time (maximum 48 business hours). The delivery times provided during the order are indicative and without guarantee. A delay does not authorize the customer to cancel the sale or refuse the goods.

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Alain DUCROCQ reserves the right to suspend any order processing and delivery in case of refusal of payment authorization by officially accredited bodies or in case of non-payment.

Alain DUCROCQ reserves the right to refuse delivery or honor an order from a buyer who has not fully or partially paid a previous order or with whom a payment dispute is ongoing.

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The shipment of available items is made after the cheque is cashed or the transfer is received. In case of out-of-stock or unavailable products, a refund will be made according to the initial payment method.

You can contact Radioelec at any time via email at the following address:


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