Long plate vs short plate 12AX7/ECC83s

[justonwo]

Is there a generalization that can be made about long plates vs short plates in preamp tubes in terms of the sound you get?

My very crude experiment on my Marshall seemed to indicate that short plates have less bass and gain than long plates. Is that true?

Just curious about the comparison.

[Timbre Wolf]

I'd generalize that long-plate 12AX7 are more articulate than short-plate: there's more air and dynamic potential (less compression) to the sound through long-plates, in my experience. I've found bass to be generally more distinct or percussive with long-plates, even though there may not be more bass (depends on the tube). Some long-plate 12AX7 break up earlier than other 12AX7, both long- and short-plates; I don't know if this is what you mean by "gain," but it isn't really the same thing.

Oh yeah, the other generalization is that long-plates are more prone to microphonics.

But when you talk about specific manufacturers/era/versions, etc., there can always be exceptions to these generalizations.

- Thom

[Speed_Racer71]

Oh yeah, the other generalization is that long-plates are more prone to microphonics.


- Thom


and some tube dealers say dont use this in a combo amp for such reasons, but im sure lots of people do ..trial and error

[Timbre Wolf]

and some tube dealers say dont use this in a combo amp for such reasons, but im sure lots of people do ..trial and error
I use 'em anywhere I want to, and relegate the microphonic ones to other uses. Trial and success!

- T

[Blue Strat]

and some tube dealers say dont use this in a combo amp for such reasons, but im sure lots of people do ..trial and error

Yep, this can prevent problems for customers who just want to plug and play and may not be open to experimentation.

[fast ricky love]

Can someone explain how to decifer between long and short plate?

[Blue Strat]

Can someone explain how to decifer between long and short plate?

Thom, got some photos handy?

[Timbre Wolf]

Thom, got some photos handy?
Sorry - I don't have the time right now. You should have some on your site, Mike.

FRL: short-plate = 14mm; long-plate =17mm

- Thom

[fast ricky love]

Thanks TW, sorry to be a bit thick but what is that measurement of...?

[Blue Strat]

Thanks TW, sorry to be a bit thick but what is that measurement of...?

The length of the plate (See discussion topic;) )

[mc5nrg]

The flattish metal pieces standing vertically inside the tube, often with ladderlike ridges.

[fast ricky love]

thanks!

[mountain blues]

Here you go — NOS Tesla and 80's Chinese:

http://www.highoctavehealing.com/Pics/tubes.jpg

[fast ricky love]

very helpful, cheers!

[Timbre Wolf]

This Tube Classics site (http://www.tube-classics.de/TC/Tubes/Valvo%20ECC83/ECC83.htm) has excellent information. Click on the Characteristics link, on the left side of the page, and you'll get a number of tube features to view. Great resource!

:BEER

- Thom