Home » Audio » Thermionic Emissions » why do different tubes sound different?
why do different tubes sound different? [message #10089] Fri, 31 October 2008 14:01 Go to next message
toob noob is currently offline  toob noob
Messages: 1
Registered: May 2009
what makes a triode sound different from say a pentode? how bout a pentode wired like a triode or even the same kind of triode but from a different maker?

i guess different wiring makes sense and maybe different materials but i would like to know more details so to know what to look for.

Re: why do different tubes sound different? [message #10090 is a reply to message #10089] Sat, 01 November 2008 17:51 Go to previous messageGo to next message
Aki is currently offline  Aki
Messages: 36
Registered: May 2009
These are tough question to answer without getting overly technical, but let me give it a try.

Same tube type from different makes can sound different. This is due to subtle differences in characteristics due to variations in electro-mechanical design and construction.

A tube's characteristics is mostly defined by its internal geometry (electrode spacing, grid alignment etc.) and cathode emission character. Each make has a different design that ends up with its own set of peculiarity like certain inter-electrode capacitance (high frequency response), internal resistance (low frequency response for output tubes) or linearity (distortion).

So the same tube type from different manufacturer, dropped into the same circuit, can sound different. This is even more pronounced when comparing same tube types with different internal design (i.e. EL34 vs KT77 or 6CA7).

With pentode vs triode operate completely differently, so it's not something you can compare just in terms of tube differences.

Since pentodes and triodes behave differently, you will use them in different circuits. Generally speaking (and overly simplified), pentodes tend to have higher gain with worse linearity and frequency response than a triode. But you get higher output from pentode and extra gain can be use for higher NFB that you might not be able to afford in a triode design. So pentode vs triode is as much a comparison of circuitry.

Re: why do different tubes sound different? [message #10093 is a reply to message #10090] Mon, 03 November 2008 11:45 Go to previous message
Wayne Parham is currently offline  Wayne Parham
Messages: 18306
Registered: January 2001
Illuminati (33rd Degree)

Great write-up, Aki, thanks!

Previous Topic: Stoetkit ECL82
Next Topic: WE-275A
Goto Forum:

Current Time: Sat Jul 02 20:52:37 CDT 2022

Sponsoring Organizations

DIY Audio Projects
DIY Audio Projects
OddWatt Audio
OddWatt Audio
Pi Speakers
Pi Speakers
Prosound Shootout
Prosound Shootout
Smith & Larson Audio
Smith & Larson Audio
Tubes For Amps

Lone Star Audiofest