Western Electric Vacuum Tubes

[CeaSaR]

Another theory from YouAllKnowBob on YouTube:
"
They appear to be high power tubes so I would assume the holes in the plates are to help keep the heat even and not build up inside. I would bet that the large punch were the orignals which required the plates to be made special and the small punch, where the plate appears to be made of a screen material, was switched to as a cost saving measure by the manufacturer. "
You can see his reply to me here: https://youtu.be/nx8RFl-17LM

Still waiting on a reply email. Going to hit up Shango066 next. Then hopefully Uncle Doug.

[CeaSaR]

Reply from Mark at BlueGlow Electronics:

small punch is pretty close to wire mesh, they are the earlier made of these and some say they sound better. I think the large hole tubes are just as good sound wise.

There is no electrical difference, just difference in how the holes were punched into the metal.

https://youtu.be/gvogDrEkEMs

[Janitor Tzap]

Reply from Mark at BlueGlow Electronics:

small punch is pretty close to wire mesh, they are the earlier made of these and some say they sound better. I think the large hole tubes are just as good sound wise.

There is no electrical difference, just difference in how the holes were punched into the metal.

Hmmm............

But if there is no electrical difference.
Why do the 310A tubes on the Tube World Express site: https://tubeworldexpress.com/collection ... mall-punch
Have such different amounts of Gain?


Signed: Janitor Tzap

[CeaSaR]

That would be the difference between the actual tube rather than the holes. If I read his comments correctly, given the same construction of the same tube, there'd be no real discernible difference if it used either the large or small punch holes.

[Janitor Tzap]

Yeah,

There are multiple things to take in account, that can effect how well the Tube performs.
Materials used to make up the tube.
How good of a vacuum was pulled when the tube was sealed, and amount of impurities left in the tube.
Are they (N)ew(O)ld(S)tock, or used.
Have the tubes been "Burned In" to setup their thermal stability, for optimal performance under normal operation of the tube.


Signed: Janitor Tzap

[CeaSaR]

2 replies from Uncle Doug:

"Thanks Glad to hear it, TV. Since we only deal with vintage tube guitar (and some PA) amps, the exotic, horrendously-expensive HiFi boutique tubes are way out of our realm. I looked up the SP and LP terms and could find no explanation. Sorry."

"Since we deal exclusively with vintage tube guitar (and occasionally PA) amps, T.V., we have no experience or knowledge on this topic. Having seen the almost absurd degree to which cork-sniffing audiophiles go to when describing vacuum tube specs, however, I will guess that the terms refer to some physical characteristic, possibly the grid perforations as you described, that differentiates two forms of the same tube. I will also guess that there are rabid fans of each type, who argue to great length over their relative merits. None of this appeals to us, so we remain blissfully ignorant regarding the topic ."

[CeaSaR]

At last, a reply from Western Electric:

Thank you for your message.

First, we believe you mean the plate/anode, not grid. Mesh plate tubes like the 310A & 348A are designed primarily for audio frequency amplifier applications where exceptionally low noise is required. All internal elements were designed to optimize that requirement, as with all similar Western Electric tube types.

We do not have a concise explanation for the mesh design, pattern differences, and the overall effect on tube performance characteristics. Back then, as today, their appearance was rather novel, new, and distinguishable from other tube types. Interestingly enough, this "novelty" factor may have played a role in the engineering team's design decision.

A mesh plate tube's functionality is essentially the same as a traditional solid plate tube: the amplification of an audio signal. With that said, the introduction of a precise mesh pattern on the plate will alter its role in attracting electrons. Whether this alters the listening experience veers into the subjective and will vary widely from user to user.

It is a fascinating question. Our engineers will be sure to reach out if anything new is learned. If you are curious about mesh grids specifically, more information may be found in RCA's Electron Tube Design.

Thank you,

Western Electric
Service & Support

[Janitor Tzap]

A mesh plate tube's functionality is essentially the same as a traditional solid plate tube: the amplification of an audio signal. With that said, the introduction of a precise mesh pattern on the plate will alter its role in attracting electrons. Whether this alters the listening experience veers into the subjective and will vary widely from user to user.

Okay,
It sounds like the hole pattern on the plate/anode was an attempt to lessen the effect of the problem of microphonics in the tube.
Which makes sense, since these are audio tubes that are designed for the output stage of an audio amplifier.
Here is the Wikipedia page on the subject of Microphonics: https://en.wikipedia.org/wiki/Microphonics


Signed: Janitor Tzap