Emission Labs 20A-Mesh / 20B / 20B-V4 / 30A Rør - Parret par/2 stk.

Guarantee: The first owner can register the tube at the Emission Labs ®website, to participate in the 5 years guarantee program.

Description / Application

EML 30A: One single tube for the first stage and driver

EML 20A-Mesh: First stage, or driver tube

EML 20B: Driver tube or output tube

EML 20B V4: Balanced Heater version of 20B

Using Directly Heated tubes in a separate pre amplifier is possible, but the design must be made with great care, and good understanding of signal to noise ratio (SNR). To keep SNR high, the volume control must always be at the output of the pre amplifier, and overall gain of the pre amp must be not higher as needed.

For these tubes we use a very fine gold grid wire, with a gain of 21x for the 20A and 20B, and 32x for the 30B. It is recommended to use these tubes transformer or choke loaded. This is because you can use them at normal supply voltage then. Of course you can also use them resistor loaded, but then you need a supply voltage of 700V or more.

The EML 20A / 20B / 30A are  universal  and stabile tubes, combining high gain with low output impedance. The 20A-Mesh and 20B at a gain of 20,  there is no comparable directly heated tube, that offers such a low  Anode impedance.  This makes it possible to use the 20B as an output tube. When using a step-up input  transformer, no additional tubes are needed , so it is possible to construct a complete HiFi amplifier with just one 20B tube.

As a driver tube,  when using a Anode resistor, 20A an 20B can work with high voltage circuits for an 845  using a high power supply voltage of around 800 Volt.   For supply voltages around 400Volt the use of a Anode choke is recommended to have sufficient Anode voltage remaining over the tube.

Features  Gold Anoded, Wolfram Grid
Center tapped filament
Slow Start filaments, for best lifetime
Hard metal Construction (Note1)
Two extra large getters
Hand blown Glass bulb
Anti-microphonic Anode- and grid  suspension
These tubes are shipped in a high quality dual box
Tube printing with real gold (metal),  red color is glass burned into the glass

Mere information HER

Varenr. 20A-Mesh 110-002-66, 20B 110-003-19, 20B-V4 110-046-56, 30A 110-014-91