6H30 VA stage? - Page 2

12B4A · 10th December 2012, 09:51 PM

When I was using this tube I had to use little ferrite beads wrapped around the wires directly connected to the grid pins along with a 1k grid stopper before things settled down.

deicide67 · 10th December 2012, 11:00 PM

Yeah,

It is probably very workable, but one was noticeable noisier than the other and the 6CG7 is very quiet. I'd be happy at this point with no more tweaks.

Thanks!

Blair

rongon · 05:57 PM

Did you build anything like post #8. Yeah, 38mA, with a 3k plate resistor would be ok. That would keep the output impedance nice and low.

I think the reason your 6N30P was behaving badly was that it's running with such low plate current. I really think it sounds best with at least 15mA plate current, per triode section. That gets it out of the "knee" in the plate curves.

deicide67 · 12th December 2012, 06:17 PM

Hi Ron,

Yes, regardless of how I swapped things according to various schematics for the tube, they were noticeably noisier than the 6CG7.

rongon · 12th December 2012, 06:19 PM

Did you try a different 6N30P tube? Or you only have that one?

deicide67 · 12th December 2012, 06:31 PM

I have two, and one was worse than the other for noise. I really only used them because they were here. I'm not bent on using them really.

rongon · 12th December 2012, 06:42 PM

Well, that is surprising, because I've used quite a few of them and had completely the opposite experience. Just the basic Electro-Harmonix, normal ones you get for way too much money. All have been very well behaved. I guess it's just one of those crazy things.

12th December 2012, 05:52 PM	#13
rongon diyAudio Member Join Date: Jul 2009 Location: Across the river from Rip's big old tree...	Did you build anything like post #8. Yeah, 38mA, with a 3k plate resistor would be ok. That would keep the output impedance nice and low. I think the reason your 6N30P was behaving badly was that it's running with such low plate current. I really think it sounds best with at least 15mA plate current, per triode section. That gets it out of the "knee" in the plate curves. Last edited by rongon; 12th December 2012 at 05:57 PM.

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10th December 2012, 09:51 PM	#11
12B4A diyAudio Member Join Date: Aug 2012 Location: Right here, on this screen	When I was using this tube I had to use little ferrite beads wrapped around the wires directly connected to the grid pins along with a 1k grid stopper before things settled down.

10th December 2012, 11:00 PM	#12
deicide67 diyAudio Member Join Date: Aug 2008	Yeah, It is probably very workable, but one was noticeable noisier than the other and the 6CG7 is very quiet. I'd be happy at this point with no more tweaks. Thanks! Blair

12th December 2012, 06:17 PM	#14
deicide67 diyAudio Member Join Date: Aug 2008	Hi Ron, Yes, regardless of how I swapped things according to various schematics for the tube, they were noticeably noisier than the 6CG7.

12th December 2012, 06:19 PM	#15
rongon diyAudio Member Join Date: Jul 2009 Location: Across the river from Rip's big old tree...	Did you try a different 6N30P tube? Or you only have that one?

12th December 2012, 06:31 PM	#16
deicide67 diyAudio Member Join Date: Aug 2008	I have two, and one was worse than the other for noise. I really only used them because they were here. I'm not bent on using them really.

12th December 2012, 06:42 PM	#17
rongon diyAudio Member Join Date: Jul 2009 Location: Across the river from Rip's big old tree...	Well, that is surprising, because I've used quite a few of them and had completely the opposite experience. Just the basic Electro-Harmonix, normal ones you get for way too much money. All have been very well behaved. I guess it's just one of those crazy things.