Long & Short Plates

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boots
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Joined: Mon Jan 17, 2011 1:26 am
Location: SW Colorado

Long & Short Plates

Post by boots »

This has probably been discussed to death, but I am fairly new here and would like to get some opinions.

What are the pros & cons of long plate vs. short plate 12AX7's? I have a number of each type.

Are the long plates more susceptible to microphonics? Are they more apt to break into a howling sympathetic feedback ("good" feedback!) at high volumes?

How about black plates vs. gray plates? The black plates seem more rare. Do they sound sweeter?
Markusv
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Location: Toronto, Canada (yes it's friggin cold!)

Re: Long & Short Plates

Post by Markusv »

longer plate structure tends to be more microphonic as a general rule (from my experience) Still I have longer plate Sylvania's and also Philips that are stable as hell

Feedback is more a dynamic between your guitar and the speaker
IMHO I want nothing to shake or rattle the tubes. That causes unwanted uncontrollable feedback

My 2 cents

Markus
.........Now where did I put it?
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David Root
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Location: Chilliwack BC

Re: Long & Short Plates

Post by David Root »

Talking about preamp tubes here.

Long plates are nice in the first stage. The silicone rings can help with microphonic tendencies if necessary. For a distortion stage eg V2 in a Dumble circuit, I use short plates. For a long tail PI, long plate again.

Black plates generally seem to have more harmonics than gray plates. The early American blackplates have this. The Euro tubes you don't seem to see black plates in but they mostly have more nice harmonics than the American gray plates.

I like Amperex particularly in Euro tubes (Heerlen factory), and Mullard. In American tubes I like RCA black plates, Raytheon ditto, and Tung-Sol long gray plates in 12AX7s. 7025s can be even better for V1, generally a bit quieter. More expensive too.
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