Pen-toad Question

[wrenchone]

I'm thinking of using a triode-connected 6EJ7/EF184 pentode with current source loading as input/driver tube for an upcoming project. I have the choice of some Euro-made tubes that have an extremely sexy-looking mesh plate (I know it sounds perverse, but I'm an engineer, so WTF) and some domestic brands that have blackened envelopes that may visually veil the inner goodies but may also have lower distortion. Comments?

 

[planet10]

I have some EF89 (IIRC) that have that lovely mesh plate... know what you mean.

dave

 

[Bandersnatch]

hey-Hey!!!,
I think the mesh is just a screen. The anode should be a small solid plate on both sides of the cathode. That said, the open structure of those tubes is decidedly nice looking, and who am I to suggest a plain looking tube...heh-heh-heh.
cheers,
Douglas

 

[DF96]

Yes, the mesh is a screen. You will find this design in many Philips group pentodes and, with a different appearance, some Russian ones. They prefer anode cooling via holes in the screen, while other makers (German and US) prefer a grey solid screen which absorbs and then re-radiates the infra-red from the anode. I don't know any valves which have a mesh plate, but it is a phrase which people outside Europe often use when describing the screen.

 

[Captain archer]

Good choice

I think it is a good choice to use these EF184 tubes in audio.
I used it in a microphone amp ones and the shield comes in very handy at low level signal aplification.

 

[wrenchone]

Yes, we all agree that the screen is very pretty. This is also a question of aesthetics vs. function. I suspect that the 6EJ7s with the blackened envelopes may be better performers based on some comments by Morgon Jones regarding 6SN7 variants with blackened vs. clear envelopes. That is, unless the screen serves a similar purpose.