Emission Labs AD1 Mesh/AD1-UX4 Mesh Rør

The EML AD1-mesh is a 15 Watt single Anode directly heater triode, electrically similar to 2A3, but AD1 works at 4Volt heaters. Though it is electrically not identical, any existing 2A3 circuit diagram can be used, provided you have the 4 Volt heater voltage available.

We have a version with the vintage 8pin Side socket, and with the 4Pin UX4 base.

AD1, the queen of European DHT triodes, is an autio tube, intended for large radios and cinema amplifiers. It was introduced just before the second world war, und during the war 'big' radios and cinemas were no item. Already during the war, military small pentodes were made. Then after the war, the high need for new made radios ended the production of the AD1, before it had really started. The market required high quantities of small size, low cost tubes. It is not known how many AD1 were made, but estimated is 250.000 pieces. Also the AD1 socket type (P8) got obsolete, because it can only be connected to 'wired' tubes, and not to the after-war tubes which typically had their pins through the glass. This socket is however amongst the best ever made. It pulls the tube inside the socket, and it closes the chassis part like a lid, so not dust can get in.

Features
An important feature of the EML AD1-Mesh, is the possibility to operate it at higher voltage than the historical tubes. Some historical tubes allowed the use above 250Volts, but not all. At higher Anode voltage, the AD1 turns into a tube with amazingly high efficiency, outdoing 2A3. However at the higher Anode voltage, it requires a higher impedance transformer.

Gray Wire Mesh Anodes, mounted on a hard metal frame for best stability.
Gold plates, Wolfram Grid
Soft rubber suspended tube base
Center tapped filament
Slow Start filaments, for best lifetime
Anode voltage maximum 400V
Can be used continuously at maximum Anode dissipation
Hard metal Construction (See Notes)
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

Filament Ratings
Filament Voltage
4.0 Volt (AC or DC)
Tolerance on filament voltage
4%
Filament Current
1,5 Ampere

Maximum Conditions
(Not possible simultaneously)
Anode Voltage
400Volt
Anode Current
60mA
Anode Dissipation
15 Watt
Grid resistor
max. 300k Ohm

Typical Tube Parameters

measured @ Ua= 250V, Ia= 60mA
Anode Impedance (Rp)
670 Ohms
Amplification Factor
4
Transconductance (Gm)
6 mA/V

Mere teknish information kan findes HER

Vare nr. 110-025-48