Let's talk triode-pentode

[Lamber]

I recently built the K-12G kit and it comes with 4 10GV8 triode-pentode tubes, 2 for each channel.

Can anyone explain exactly what a triode-pentode tube is? Why do they use them? I'm new to tubes and I haven't been able to find much literature on triode-pentode tubes.

thanks!

 

[vinylkid58]

Can anyone explain exactly what a triode-pentode tube is?

Triode and Pentode sections in one envelope. I couldn't find a complete data sheet for the 10GV8, but you can see the pin-out at least:

NJ7P SQL Tube Database Query

I'm new to tubes and I haven't been able to find much literature on triode-pentode tubes.

You can search for data sheets on Frank's site: Frank's Electron tube Pages

 

[Soonerorlater]

The 10GV8 I believe was developed for use in a television set as a "sweep" tube. Putting a triode valve and a pentode valve in one tube saved space.

Here's a good read. ( Don't be put off by the guitar amp stuff )

How to design valve guitar amplifiers


Here's a link to the 6GV8 (ECL85 ) a 6.3V heater version of the 10GV8

http://www.r-type.org/exhib/aaa0427.htm

 

[kstagger]

another popular triode/pentode tube is the 6BM8. Having the two different types in the same bottle allowed easy (and cheap) amplification. In this case, the single triode would act as a driver for the pentode section. A simple way to squeeze a few watts out for a little console, radio, or portable record player.

 

[Soonerorlater]

The K502 ( very similar to your K12G ) uses the 11BM8 tube. It is equivalent to the 6BM8 except it requires 10.7Vac for the heaters instead of 6.3Vac. Another nice triode-pentode is the 6GW8 ( ECL86 ).

 

[Miles Prower]

Can anyone explain exactly what a triode-pentode tube is? Why do they use them? I'm new to tubes and I haven't been able to find much literature on triode-pentode tubes.

Just what it sounds like: a dual VT that has a triode and a pentode in the same bottle. The small signal types were frequently used as oscillator/mixers for TV and FM receivers. The large signal types were used in color TVs as plate coupled multivibrators and vertical deflection PAs.

The small signal types can be used as paraphase splitters or active regulator error amps; the large signal types can use the triode as a grid driver for the pentode final. Quite a few of these have good linearity and audio performance.

 

[Cassiel]

Triode and Pentode sections in one envelope.

Ladyboys.