Not just an replacement, but an improvement!

New Type with gray mesh wire
Uploaded: 16-Sep-2018 13:24ate -->

Did you know? Emission Labs was the first company to re-introduce the 45 tube again, in the year 2001.


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

Initially we build the 45 using the larger glass bulb of the 300B. Later, several general improvements were made to all of our tubes, and also to the 45. The main change, optically was the smaller glass size. Electrically we changed to the tube to a "slow starter" tube, and this also reduced harmonic distortion. Vintage 45 will begin to work almost immediately after switch on, whereas EML needs a few seconds before anode current begins to ramp up. This will greatly improve the lifetime expectation of the tube, and also virtually eliminate the classical problem of heater breakage with older Directly Heated tubes. We believe at EML, we exceed the lifetime of the original RCA tubes by far. Fair enough we have to say that this was only possible, due to our larger size construction, compared to vintage tubes. However miniaturization is no target any more today, and some of the typical issues having to do with that, such as distortion, grid current, heater breakage, and too early loss of transconductance, just do not occur with the EML45. Moreover, this allowed us to build a higher power version of the 45, called 45B which has a separate data sheet.


We have now also build a mesh version of this tube, called EML 45-mesh.  It features a mesh window in the plates.  This combines the electrical stability of solid plate tubes, with the non-resonance mesh material. We think this is the most ideal combination for a low power audio tube.

Sound character of the 45 mesh tube

For general information on the sound character of this tube, we have the EML-45 data sheet. All features of the standard 45 are also implemented in the the 45 mesh. What is mesh? By the dictionary this means woven metal wire. The Chinese fool you with punched plates, the difference you can see already with a lens. Read here for a warning information. Mesh wire has a very high mechanical damping factor due to friction between the wire crossings. So it is free of any ringing effects. It is even used as damping system in instruments. If you make an object from mesh wire, and knock on it, there will be no bell sound. So this is the only mechanical proof we can find for the difference in sound. From listening tests an improvement in sound is confirmed by many users worldwide, mainly when using very high quality loudspeakers.

We are often asked to explain the sound difference. It is not easy to explain this, but when a tube is given mesh plates, something magic happens to the sound. A more transparent sound stage appears in many cases, meaning a more realistic stereo reproduction of the original sound recording.  With mesh tubes you will enjoy the very best of what small triodes have to offer.  Read this note if you are interested in very technical explanations.


  • Gold Grid
  • Center tapped filament
  • Gray Wire Mesh
  • Nano Ampere range grid current, vs NOS tubes which can have sometimes 2uA.
  • Center tapped filament
  • 30% lower distortion compared to any other 45. Read here.
  • 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
  • Machined, solid tube base pins for highest contact precision. YAMAMOTO tube sockets highly recommended.
  • Gold Anoded pins, black ceramic socket. (White bottom.)

EML 45 MESH Filament Ratings 
Filament Voltage 
= 2.5Volt (AC or DC) 
Tolerance on filament voltage
Filament Current 
~ 1.5Ampere 
EML 45 MESH Maximum Conditions
Plate Voltage 
Plate Current 

Continuous Plate Dissipation for new types with gray mesh plates:

13,5 Watt (Note4)

Continuous Plate Dissipation for older types with white mesh plates:

11 Watt (Note4)
Power Output in Class A 
3.5 Watt 
Grid resistor (Read note5)
500k Ohm
EML 45 MESH Factory Test conditions 
Plate Voltage 
Plate Current
EML 45 MESH Typical Data 
Plate Voltage 
Plate Current 
Plate Dissipation 
9.9 Watt
(only possible with mesh tube)
Grid Voltage 
Plate Impedance (Rp)
1750 Ohm
1670 Ohm
1600 Ohm
Amplification Factor 
Transconductance (Gm)
Power Output in Class A 
1.6 Watt 
2 Watt 
2.5 Watt 
Load Impedance (Ra)
3900 Ohm
5000-5600 Ohm
EML 45 Typical Data  Push Pull Application Class AB2
See also note 6 at page bottom.

Self Bias
Auto Bias
Plate Voltage 
Plate Current  2) 3)
Plate Dissipation 1) 3)
7.9 Watt
Grid Voltage  4)
Bias Resistor
775 Ohm
Power Output in Class A  2)
18 Watt 
12 Watt 
Total Distortion
Load Impedance (Raa)
3200 Ohm
5060 Ohm

1) Values for one tube
2) Values for both tubes together
3) Value are for zero Signal in this table, but will rise at higher signal. Avoid overdrive which exceeds maximum plate dissipation of 11 Watt per tube.
4) Adjust grid voltage for plate current of 28mA at zero signal

EML 45 MESH Mechanical Data 
Size including Socket: 

155 x 60 mm

Single Tube weight 
145 Gram 
Shipment weight for 
pair in gift box 
700 Gram
  • Note 1)  Hard-metal filaments prevent filament breakage with DHT Tubes.  This material has a higher melting point than the classical nickel wires. Wolfram grids  allow the most precise grid wire distance, because wolfram is an extreme hard metal.   This ensures better grid  precision, which gives uniformity and better linearity at the low end of the tube curves
  • Note 2)  Individual Test data, such as:  Matching Data, Grid Current, Vacuum, Filament Current, etc.,  are on the Certificate that comes with each individual Tube.  Each tube is numbered, inside the bulb  with a metal Tag
  • Note 3)  Tube Curves:  Made on the The Sofia Curve tracer, with courtesy of AMR, Wisconsin, USA.
  • Note 4) Historical 45 tubes have a maximum dissipation of 11 Watt, which means the maximum voltage and maximum current can not be applied at the same time. Our new type, gray wire mesh 45 (shipped since Q3-2006) has 13,5 Watt maximum dissipation, meaning maximum voltage and maximum current can be applied at the same time. Older types with white mesh have also 11 Watt maximum
  • Note 5) EML45 first generation (from before 2004) and all VV45 have a maximum grid resistor value of 100k. In most cases it will be possible to exceed this 100k, though we do not guarantee this. If you do, check if the bias current stays as stablie as before, but you need to check this at maximum signal level.
  • Note 6) In a class AB2 amplifier, the tubes are operated mildly into positive grid voltage, and output power as published here should not tried to be exceeded. The 2nd Harmonics resulting from this, are cancelled by virtue of the Push Pull circuit. A sufficient low impedance driver stage is needed for class AB2. This can be achieved with a step down interstage transformer, as recommended by the RCA receiving tube manual 1934, Page 93.

EML 45-mesh

High Resolution Pics

Nice 1929 Article

Plate curves


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