[interben]

Hi Guys I am new to the tube scene....
I have recently setup a tube headphone amp and electrostatics.
The amp takes 4 tubes and I recently purchased 4 SVETLANA EL34 MATCHED QUADs
I also purchased a Psvane quad set as well.

Can someone explain the different roles tubes play and the different categories of tubes? Is it purely mounting?

Are matched tubes tested for output in order to match them?
Are there affordable devices for testing them?
Thanks

[FullRangeMan]

Welcome aboard 
Can someone explain the different roles tubes play and the different categories of tubes?
It would take a entire tome, but in a fast way:
Triode have 3 elements(cathode, grid, anode or plate)
Tetrode=4 elements: cathode, grid, screen, anode.
Pentode=5 elements: cathode. grid, screen, supressor, anode.
Decatron=10 elements.
Is it purely mounting?
No
Are matched tubes tested for output in order to match them?
No, the tubes are matched to have the same level of electrical performance at output, for there is no audible differences in music and imbalances in the amp circuit.
Usually amps that need matched tubes have no individual Bias.
Are there affordable devices for testing them?
I afraid no. In the past there was some simple gadgets(good/bad) but they are not reliable, the user may feel a false sense of safety in regards the tube.

[FullRangeMan]

A deep book that show in detail how tubes works:
http://www.amazon.com/Inside-Vacuum-Tube-John-Rider/dp/1882580427/ref=sr_1_1?s=books&ie=UTF8&qid=1423625521&sr=1-1&keywords=inside+the+vacuum+tube

[kentajalli]

I don't know if I understand your question, but here's my 2 cents.
Tubes (valves to us Brits) are the active components that actually do the amplifying, much akin to transistors and chips.
Indeed early transistors were modeled on tubes.
There are different kinds of tubes, as my fiend has explained in his post.
Just to add that, you can not get power and performance at the same time (that's life) so they made different tubes for different purposes from one end to another, and some  in between.
One way to get more power is to use pairs of tubes to amplify the signal.
In the absence of individual controls for each tube, we use matched tubes in order to share the load evenly and not burden one tube while another is relaxing.
Also by using pairs of tubes in opposite direction and adding their outputs together, we can cancel certain shortcomings (distortions or noise) -
if there is an imbalance ( not matched) then these distortions do not cancel each other effectively.
Hope this is enough, to get you interested in the subject.

[FullRangeMan]

This 3 video set will show a useful understanding from tubes working to the OP.
https://www.youtube.com/watch?v=UM3av6moJd4

[Guy 13]

This 3 video set will show a useful understanding from tubes working to the OP.
https://www.youtube.com/watch?v=UM3av6moJd4

Hi FullRangeMan,
thanks for the link, lots of good stuff there...

Guy 13

[G Georgopoulos]

Hi FullRangeMan,
thanks for the link, lots of good stuff there...

Guy 13

hi guy

yeah it tells how tube works in kindergarden terms,sorry i had to say this...

[Guy 13]

hi guy

yeah it tells how tube works in kindergarden terms,sorry i had to say this...

For you Mr. Georgopoulos, it's Guy with a capital letter " G "
and not guy as you wrote it. ( )
Of course, we cannot all be smart like you and FullRangeMan intentions were good
by posting that link,
because many of us, even if not completely ignorant on tube technology,
are always interested to learn something, even if it's just small details
and it's fun to see it via a video instead of just plain text.
Sorry, I had to say it... 

Guy 13
 

[FullRangeMan]

hi guy

yeah it tells how tube works in kindergarden terms,sorry i had to say this...

Maybe George could cheer us with its highly literate version.

[G Georgopoulos]

here i will show you how to transfer gain from one stage onto the next

the plate resistor is the output impendance of a triode

to calculate the coupling capacitor impendance

is output impendance =< /10th the o/p impendance

so if we have o/p impendance 68k then the coupling capacitor impendance becomes

6.8k or less

we calculate this at the lowest coupling frequency say 20hz

the formular for this is

1/(6.28 x 20 x 6800) = 1uf

the input impendance of a triode is the grid resistor of the next stage

this should be the output impendance => x 10 times the o/p impendance

68k x 10 = 680k or more

fullrangeman hope this helps...

[FullRangeMan]

Sorry George the subject are tubes working, but circuitage also is interesting.

[Guy 13]

Hi Mr. Georgopoulos,
nice to know that you are a knowledgeable person
when it comes to tubes (Design),
but I think what FullRangeMan was trying to do,
its just let us know about basic of tube.
The formulas that you have shown us,
might be a little too advance for the average Audio Circle members. 
But by showing us what you know
and sharing with us your knowledge on tubes is a good idea.
Just wanted top let you know.

Guy 13

[kentajalli]

. . .  might be a little too advance for the average Audio Circle members. 

Excuse me! Errrr . . .  .

[interben]

Appreciate All the input!

[G Georgopoulos]

Hi Mr. Georgopoulos,
nice to know that you are a knowledgeable person
when it comes to tubes (Design),
but I think what FullRangeMan was trying to do,
its just let us know about basic of tube.
The formulas that you have shown us,
might be a little too advance for the average Audio Circle members. 
But by showing us what you know
and sharing with us your knowledge on tubes is a good idea.
Just wanted top let you know.

Guy 13

Hi Guy13

thanks for your kind words
the formular i showed is taught in basic electronics and is transposition of
Xc=1/(2p x F x C)
it became
C=1/(2p x F x Xc) in my post

thanks also to kentajalli and interben

learning tubes is fun...


ps
more on the formula,google "capacitive reactance"
or
here http://en.wikipedia.org/wiki/Electrical_reactance
or
here (better) http://www.electronics-tutorials.ws/filter/filter_1.html

[interben]

Just on the tube topic.....
Watched a great video on the Mullard factory...
https://www.youtube.com/watch?v=GDvF89Bh27Y
and this cool little video on different tubes being tested
https://www.youtube.com/watch?v=Kf1MGEOQXZQ

I have purchased a tube amp but am waiting to run a dedicated circuit to run it from before using it.....
It requires matched quads...
I purchased some
psvanes 6ca7-t2
Svetlana el34 and it came with
Mullard el34s
So I am a bit excited.....
It's an electrostatic headphone rig
Again I appreciate now having a basic understanding of Bias and Amp rating in regards to tubes!
I am sure after I have burnt all these things in I will be on the hunt for some old school tubes to try...

[interben]

Just reread George's post...
So is it a tubes impedance that affects it's ability to reproduce the signal when amplifying?
Hence the different "colouring" each tube design provides?
And can I assume its the different materials and plate shapes that create the differing impedances?

or am I way off

Thanks again
Ben

[ACHiPo]

Just on the tube topic.....
Watched a great video on the Mullard factory...
https://www.youtube.com/watch?v=GDvF89Bh27Y
and this cool little video on different tubes being tested
https://www.youtube.com/watch?v=Kf1MGEOQXZQ

I have purchased a tube amp but am waiting to run a dedicated circuit to run it from before using it.....
It requires matched quads...
I purchased some
psvanes 6ca7-t2
Svetlana el34 and it came with
Mullard el34s
So I am a bit excited.....
It's an electrostatic headphone rig
Again I appreciate now having a basic understanding of Bias and Amp rating in regards to tubes!
I am sure after I have burnt all these things in I will be on the hunt for some old school tubes to try...

Interben,
Give Brent Jesse a call/email and he can hook you up with a wide variety of matched tubes. His prices are competitive and seems to do a great job characterizing and prepping tubes.
Brent Jesse Recording&Supply 847-496-4546

[FullRangeMan]

Just reread George's post...
So is it a tubes impedance that affects it's ability to reproduce the signal when amplifying?
Hence the different "colouring" each tube design provides?
And can I assume its the different materials and plate shapes that create the differing impedances?

or am I way off

Thanks again
Ben

You right. There is some hi impedances tubes that have great sound, as 211, 805, GM70 etc
And some low impedances tubes that also have great sound as EL34.

[kentajalli]

You right. There is some hi impedances tubes that have great sound, as 211, 805, GM70 etc
And some low impedances tubes that also have great sound as EL34.

I disagree in general terms.
The impedance's of a tube, do not have a direct relationship to colour! of its sound.
If designed properly, it should not add any colour (= distortion).
Colours and textures in tubeamps are in guitar amps, where these distortions are deliberately allowed to make that distinct guitar sound.
in HiFi we do't want any colours.