Not just an replacement, but an improvement!

EML 45 MESH

Data sheet. for new Type with gray mesh wire

Last Data sheet. revision:
2011-Oct-10


Description 

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.

Features
  • Gold plated Grid
  • Center tapped filament
  • Gray Wire Mesh
  • 30% lower distortion compared to any other 45. Read here.
  • Hard metal Construction (Note1)
  • Two extra large getters
  • Hand blown Glass bulb
  • Anti-microphonic plate- 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 plated pins,  black ceramic socket.  (White bottom.)

EML 45-mesh


High Resolution Pics


Nice 1929 Article


Plate curves


Distortion

EML 45 MESH Filament Ratings 
Filament Voltage 
= 2.5Volt (AC or DC) 
Tolerance on filament voltage
5%
Filament Current 
~ 1.5Ampere 
EML 45 MESH Maximum Conditions
Plate Voltage 
300Volt 
Plate Current 
45mA 

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 
250V 
Plate Current
34mA 
EML 45 MESH Typical Data 
Plate Voltage 
250V
275V
300V
Plate Current 
34mA
36mA
39mA
Plate Dissipation 
8.5Watt
9.9 Watt
11.7Watt
(only possible with mesh tube)
Grid Voltage 
50Volt
56Volt
58,6Volt
Plate Impedance (Rp)
1750 Ohm
1670 Ohm
1600 Ohm
Amplification Factor 
3.5
3.5
3.5
Transconductance (Gm)
2mA/V
2.1mA/V
2.2mA/V
Power Output in Class A 
1.6 Watt 
2 Watt 
2.5 Watt 
Load Impedance (Ra)
3900 Ohm
4600Ohm
5000-5600 Ohm
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)  Those DIY that loaded a tube with a power resistor instead of a loudspeaker, may have noticed the tube produces some sound by itself, without loudspeaker. This is caused by the electrical field force between the two plates of the tube, being a function of plate size, plate distance and momentary plate voltage. The mechanical force is considerable at high voltage, and proportional to the plate voltage. This will cause the plates to move with the sound frequency. Of course there is no sound in vacuum, but mechanical paths to the glass bulb do exist. With mesh tubes, the electrical field force is the same as with solid plate tubes, but there is less mechanical ringing caused by this. Another thing that happens, some portion of the electrons escape thought the holes in the mesh. These still return to the plates, since they search to move the highest positive voltage. They do however hit the plate from the outside, instead of from the inside. This is an amazingly large portion, and from some faulty tubes we were able to estimate this with perhaps 25%. Even some electrons will bounce on the glass first, and then be reflected back to the positive plate. These bouncing electrons can be as much as 5%, and this causes the blue glow on the glass, which is typical for mesh tubes. Interestingly these electrons are not lost, and stay a normal part of the plate current still, without affecting the tube curves even. The longer path means some longer traveling time, but this has no effect in the audio range, since the actual time delay is only relevant in the 100 MHz range. So the longer traveling time can not be be explanation for the magic sound of the mesh tubes. What remains is another path, so a part hits the plate from the outside. It can be expected, there is some sound effect from this, but actually we have no good explanation as to why mesh tubes sound different.

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