2A3-Mesh Data Sheet


2A3 Mesh tube

The EML 2A3 mesh tube is a plug & play, direct replacement for original the RCA 2A3 tube. It features a mesh window in the Anodes. This combines the mechanical stability of Solid Plate tubes, with the properties mesh materia, which is soft, and has a resonance damping function. We think this is the most ideal combination for a low power audio tube.

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Guarantee program for first owner.

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

Sound Character of the EML 2A3-mesh

When a tube is given mesh Anodes, something magic happens to the sound. We believe this is caused by the high damping properties of the wire mesh material. When using mesh tubes, you will experience what people call a more "transparent" sound stage, meaning a more realistic stereo reproduction of the original sound recording. With this quality product you will enjoy the very best of what small triodes have to offer.

The EML 2A3-Meshtube is constructed for lowest microphonics. All critical parts, like filaments and grids are made of hard metal for higher reliability and reproducible quality. The tube base is now glued on the glass with anti-vibration rubber.

We have two versions for the heater: Normal heater, or Center Tapped heater.

EML 2A3-Mesh Filament Ratings
Filament Voltage
2.5Volt (AC or DC)
Tolerance on filament voltage
2.4 ... 2.6V at Tube pins
2.5 ... 2.7V at Socket pins
See also the Note about Heater Voltage
Filament Current
EML 2A3-Mesh Maximum Conditions
(not possible simultaneously)
Anode Voltage
Anode Current
Anode Dissipation Continuous

Highest possible Grid to ground resistor, Single Ended.


Highest possible Grid to ground resistor, Push-Pull.

EML 2A3-Mesh Factory Test conditions
Anode Voltage
Anode Current
Control Grid Voltage
as needed for 60mA
tested at 60mA
Typical application
Singe Ended (SE) Recommended operating point
All bias methods are possible
Anode Voltage
Anode Dissipation
Anode Current
Control Grid Voltage
Anode Impedance (Rp)
800 Ohm
Amplification Factor
Transconductance (Gm)
Load Impedance (Ra)
2500 Ohm
Power Output @ Ra = 2500k
3.5 Watt
Typical application
Push Pull (PP) Recommended operating point
Auto Bias
Anode Voltage
Anode Current at zero signal
(value is for one tube)
Cathode Resistor
(Common Resistor for one tube)
780 Ohms
Load Impedance (Raa)
5000 Ohm
Power Output @ Raa = 5k
10 Watt
Curves of 2A3 tube
EML 2A3 Average Plate Characteristics. See Note 3
EML 2A3-Mesh Mechanical Data

Size including Socket
(but excluding pins)

147 x 60 mm

Weight of one tube:
140 Gram

Pin 1: Heater1
Pin 4: Heater2
Pin2: Anode
Pin3: Grid

UX4 Base

Size including Socket
(but excluding pins)
147 x 60 mm

Weight of one tube:
140 Gram

Pin 1+2: Heater1
Pin 6+7: Heater2
Pin 8: Center Tap (Cathode)
Pin3: Anode
Pin5: Grid
Pin4: Not on tube base

Octal Base
(V4 Version)
Shipment weight for pair in gift box:
730 Gram
  • Gold Plated Grid (Note8)
  • Gray Wire Mesh
  • Soft rubber suspended tube base
  • Center tapped filament version available (order V4-Version)
  • Electrically compatible to vintage 2A3 tube by RCA.
  • 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
  • YAMAMOTO tube sockets highly recommended.
  • Gold Plated pins,black ceramic socket.(White bottom.)

Note 1) Hard-metals like Molybdenum and Wolfram are used in EML tubes. Though these metals are more costly to use and to buy, than classical tube nickel. At critical places, we use hard metal for better geometry. This results in best tube parameters, also after shipment. You will still find EML tubes mechanically much more stabile than comparable tubes on the market.

Note 2) Individual Test data, such as: Matching Data, Grid Current, Vacuum, Filament Current, etc., are on the Certificate that is on the outside of the tube box. Each tube is numbered from the inside, with a metal Tag

Note 3) Average Plate Characteristics: Made with the Sofia Digital Curve tracer.

Note 6. Some competitors claim to be the only one with a center tapped filament, but this is not true. At EML we build since approximately 2005 all triodes center tapped, not just the 300B. Such tubes which we offer in V4-Version have an electrical connection to the center tap. Thus offering a real cathode connection.

Note 7) Heater Voltage: Some people experiment with lower filament voltage, to expect better lifetime. This is essentially wrong to do. If the magic was that easy, we would make the tubes like this ourselves. Under Heating can lead to early loss of emission, though new EML tubes will fully recover once the heater voltage is corrected, older tubes will recover only partially. The specified filament voltage at 0% tolerance is the one for best lifetime. The voltage we specify, is at the TUBE PINS itself. Any voltage drop by the socket contacts must be compensated for. For 2A3 tubes, some sockets have 50mV voltage drop per pin, because the heater current of 2.5 Ampere is very high. Causing a total drop of 0.1V for both pins together. So a voltage of 2.6Volts at the socket pins is needed, to make sure there is minimum 2.5 Volts at the tube pins. If operated at 2.5V at the SOCKET Pins, this is the lowest limit, because at the TUBE Pins this means only 2.4V, at the lowest end of the tolerance, thus not achieving the highest lifetime.

Note 8) Gold Plated grids have a few advantages. Amongst other this will give better bias stability of the tube, some protection against accidental overload, and better linearity of tube curves.

Note 10) Some competitors offer what they call "Mesh" tubes, which are no mesh tubes at all, but only give the optical illusion of this. See our warning page for FAKE Mesh tubes.