Tetrode or Pentode? / Tube info

[FrankRoss]

Tube Info

Other than EI, who makes the Fat Bottle 6CA7 tube which is currently and readily available? Can you point me to any web sites?

!!I'm NOT refering to the EL34/6CA7 skinny tubes!!


Thanks!

 

[fdegrove]

Hi,

The only other fat boy 6CA7s I know of are the EHs that are said to be a copy of the Sylvania/ECG 6CA7.

They're made by Reflektor in Russia.

Cheers,😉

 

[FrankRoss]

Tetrode or Pentode?

I'm really trying, but I'm not a sound or electrical engineer by any stretch! Based on what I read, are either the EI or the Electro Harmonic tubes actually a true 6CA7, and not something made with a bigger bulb just for looks?

I'm trying to find a TRUE Big Bottle 6CA7, the ones that everybody talks about. I know that there are EL34/6CA7 tubes available, but they are not true 6CA7's, or at least not the Big Bottle design of which I'm refering.

Can anybody elaborate on the links below and finally tell me what currently available 6CA7's are on the up and up (not just labeled as such)?


This eplains the difference between Tetrode and Pentode tubes:

http://www.mosweb.com/tp2.htm



Here's the Electro Harmonix 6CA7 tube (click on pic to enlarge):

http://www.thetubestore.com/ehx6ca7.html



And the EI 6CA7 tube:

http://www.upscaleaudio.com/rare/ei6ca7.jpg

 

[FrankRoss]

But is the EH fat boy a "true" 6CA7 or is it merely labeled as such and just simply an EL34 with a bigger bottle?

 

[fdegrove]

Hi,

This is what they say about it themselves:

EH 6CA7

Note that they claim it's a tetrode.

Other than that, I just don't know.

Cheers,😉

 

[FrankRoss]

I'm familiar with that link, but isn't the EL34 a tetrode? That would lead me to believe that the 6CA7EH is just an EL34 with a bigger piece of glass - correct me if I'm wrong?

 

[dhaen]

I've always thought the EL34 was a penthode (as Frank calls 'em)...

 

[fdegrove]

Hi,

the EL34 was a penthode (as Frank calls 'em)...

😉

Yep,Penta Hodos.

EL34 HISTORY.

German only but interesting nonetheless.

Cheers,😉

 

[imix500]

Wow, Looks like a thorough history. Wish I spoke German.
🙂

 

[fdegrove]

Hi,

Wow, Looks like a thorough history. Wish I spoke German.

If there's anything in particular you'd like to see translated, just ask...
As long as I don't have to translate the pics....😉

Cheers,😉

 

[imix500]

Thanks Frank, I wouldn't ask you to do all that work, but I haven't been able to find a good history in English about the illustrious EL34.
-Ricky

 

[DrDeville]

Wow, Looks like a thorough history. Wish I spoke German.
🙂

You don't have to. 😀

Just go to one of these sites, paste in the link for the website you want to translate, select the translation languages, click, and your life is jelly! 😎

Best,

George "Babblefish" Ferguson

http://www.worldlingo.com/products_services/worldlingo_translator.html

http://www.google.com/language_tools

 

[fdegrove]

Hi,

While Worldlingo seems to be on strike tonight I thought I'd give Googles' service a go.

I must say I'm impressed. This is by far the best translation I've seen.

If I find the time I may just as well touvh up the lot, turn it into pdf format and archive it on CD-R for future reference.

Thanks, George 😉

 

[imix500]

That's really cool George, Thanks!

 

[DrDeville]

You are all very welcome. 😀

Consider it my first reciprocation of all the generosity
you have shown me in my incessant questions.

Best,

George Ferguson

 

[cogsncogs]

Hi Frank,

Thanks for the history lesson! The tree at the top of the page explains it all. Phillips invented the pentode, RCA as a counter the Beam tetrode beacause of the kink that all tetrodes produce when the plate voltage falls below the screen (G2) voltage. IIRC the so called kinkless tetrodes. That's also why Phillips invented the power pentode because of that kink. That's how the U.S. version 6CA7 got around the patent issues.
There's an article in one of my Audio Express mags. that covers this. I'll have to dig it up.

Wayne