6N6P question

Tyimo · 9th January 2010, 09:27 AM

Hi!
I would like to ask from the experienced peoples:
- Does this tube need a grid resistor (grid stoppers)?
- What is an ideal value of the output bleeder resisitor? (after the output cap)

Greets:

Tyimo

Allen Wright · 9th January 2010, 10:05 AM

This tube, being hi gM and low impedance will CERTAINLY need a grid stopper. Only low gM tubes run in high impedance circuits don't need them, all other tubes it's safer to use them, at least at first.

Practical experience!

Regards, Allen

Tyimo · 9th January 2010, 11:07 AM

Thanks Allen!
Yes, I thought to use 1K for grid stopper, but a saw many design without it and it confused me.

What about the output bleeder resistor? 1M or 470K? I saw even 10K.
Tyimo

Zen Mod · 9th January 2010, 12:11 PM

Quote:

Originally Posted by Tyimo

Thanks Allen!
Yes, I thought to use 1K for grid stopper, but a saw many design without it and it confused me.

What about the output bleeder resistor? 1M or 470K? I saw even 10K.
Tyimo

bleeder resistor is there just to discharge output cap , in situations where same is "loadless" .

lower in value - faster discharge..... nothing more

feel free to use anything form 100K , up to 1M

Allen Wright · 9th January 2010, 12:30 PM

Tyimo,
I would start with a 1k grid stopper - RIGHT at the grid pin on the tube socket - and when it's all working maybe you could try reducing it down to say 330 ohms, but I wouldn't trust anything less than that. Unless you have 250MHz scope/or spectrum analyser and know how to use it.

What ZenMod says about the bleedeer R is correct, I always use 1 meg. 10k would be just stupid, IMO.

Regards, Allen

Tyimo · 9th January 2010, 06:31 PM

Thanks Zen Mod and Allen!

9th January 2010, 09:27 AM	#1
Tyimo diyAudio Member Join Date: Nov 2002 Location: Hungary	6N6P question Hi! I would like to ask from the experienced peoples: - Does this tube need a grid resistor (grid stoppers)? - What is an ideal value of the output bleeder resisitor? (after the output cap) Greets: Tyimo

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9th January 2010, 10:05 AM	#2
Allen Wright R.I.P. Join Date: Dec 2001 Location: Schaffhausen Switzerland	This tube, being hi gM and low impedance will CERTAINLY need a grid stopper. Only low gM tubes run in high impedance circuits don't need them, all other tubes it's safer to use them, at least at first. Practical experience! Regards, Allen

9th January 2010, 11:07 AM	#3
Tyimo diyAudio Member Join Date: Nov 2002 Location: Hungary	Thanks Allen! Yes, I thought to use 1K for grid stopper, but a saw many design without it and it confused me. What about the output bleeder resistor? 1M or 470K? I saw even 10K. Tyimo

9th January 2010, 12:30 PM	#5
Allen Wright R.I.P. Join Date: Dec 2001 Location: Schaffhausen Switzerland	Tyimo, I would start with a 1k grid stopper - RIGHT at the grid pin on the tube socket - and when it's all working maybe you could try reducing it down to say 330 ohms, but I wouldn't trust anything less than that. Unless you have 250MHz scope/or spectrum analyser and know how to use it. What ZenMod says about the bleedeer R is correct, I always use 1 meg. 10k would be just stupid, IMO. Regards, Allen

9th January 2010, 06:31 PM	#6
Tyimo diyAudio Member Join Date: Nov 2002 Location: Hungary	Thanks Zen Mod and Allen!