investigating the russian 6S6B-V tube

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How much less gain?

http://livinginthepast-audioweb.co.uk/index.php?p=valvegaincalcs
"Even the sparsest information usually lists the µ value, but be aware that the value can change somewhat with other parameters, so it should be accompanied by specific values for Va and Ia. That is, the stated µ is achieved with these other values being true. If the valve is a high gain triode like e.g. ECC83, then the µ doesn't usually change greatly, which makes it easier. If it's a low gain triode like ECC82 etc., then it can vary more so with changes in Va and Ia, so check it with the graph for the particular value of anode current you want to operate."
 
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I would like to find

RI is in KOhm
U = (mu) in MOhm
RL is 95,24
How can i do that ?
Thank you





6S6B-V en Mohms.png

Technical specifications:
  • Heating voltage: 6.3V
  • Anode voltage: 120V
  • Grid bias voltage: -2V
  • Heating current: 200 ± 20mA
  • Current in the anode circuit: 9 ± 2.5mA
  • The steepness of the characteristic: 5mA/V
  • Gain 25
  • Input impedance at a frequency of 5MHz: about 16KOhm
  • Service life: not less than 5000 hours.
 
According to that graph, at about 1mA anode/plate current, which is what we're looking at in microphones, Ri looks to be about 14Kohm.

You won't find "mu in MOhm" because mu has no dimension, it's a ratio (amplification factor; output amplitude divided by input amplitude).
At the above-mentioned 1mA, mu should be about 20-21. Maybe. Not sure the datasheet mentions the exact conditions (surrounding components, supply voltage etc) those figures were measured in.

What is "RL"?

That being said, you can find the gain of your circuit by applying a fixed, known-amplitude voltage to the input of your circuit (tube grid), and measure the amplitude you get at the anode (ideally after the DC-blocking capacitor, to avoid poking into high voltages).
 
Khron said:
According to that graph, at about 1mA anode/plate current, which is what we're looking at in microphones, Ri looks to be about 14Kohm.

You won't find "mu in MOhm" because mu has no dimension, it's a ratio (amplification factor; output amplitude divided by input amplitude).
At the above-mentioned 1mA, mu should be about 20-21. Maybe. Not sure the datasheet mentions the exact conditions (surrounding components, supply voltage etc) those figures were measured in.

What is "RL"?

That being said, you can find the gain of your circuit by applying a fixed, known-amplitude voltage to the input of your circuit (tube grid), and measure the amplitude you get at the anode (ideally after the DC-blocking capacitor, to avoid poking into high voltages).
Click to expand...
Thank you very much Khron
I saw this value
https://soviet-tubes.com/product/6s6b-i-tube-triode/
  • Current in the anode circuit: 9 ± 2.5mA
Does it has anything relating to mu? if yes what could be mu.
Yours Sincerely
 
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Given the size of the tube and the order of magnitude of that figure, sounds more like "maximum anode current" to me, but i could be wrong.
 
Khron said:
Given the size of the tube and the order of magnitude of that figure, sounds more like "maximum anode current" to me, but i could be wrong.
Click to expand...


Thank you Khron
I'm very interested with this conversation
If the current in the anode circuit: 2.5mA then what is mu?
Can you tell me where you have found 1mA as mu in the document?
1690455929595.png
If the greater power distributed 1,2ma then what is mu?







anod-6.png1690456359091.png
Thank you
Sincerely yours
 
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Echoing what RuudNL says, I have plenty of 6S6B and never had any that even varied a dB. More likely, you should check the biasing of the tubes in your circuit. The datasheet might say 9mA but that's at ONE specific point in the operation. In microphones, you are generally only running the tube at 500uA-1mA. You need to measure the anode and cathode voltage as well as the voltage drop across the B+ supply resistor to find the operating point. In most uses, the Ri will be around 12-14K and mA/V is around 1.6-1.8
 

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