Quiet Tube

Audio_idiot · 30th March 2007, 04:34 AM

Hi guys,

I am looking for non-microphonic, quietest 9-pin twin triode tube. As I am frustrated from differentiating tube (internal) noise and other externally generated tube oise.

Please kindly recommend

Thanks

rcavictim · 30th March 2007, 04:54 AM

Try a 2N6CG7.

Geek · 30th March 2007, 07:42 AM

I have a box full for JAN GE 5751's that fit that description

SY · 30th March 2007, 07:53 AM

Quietest in what circuit? Context is everything.

oshifis · 30th March 2007, 08:08 AM

I used Tungsram PCC88 for moving coil amplifier, and I could reach 60 dB S/N ratio (A weighted). E88CC is also very good, although a bit less quiet.

Tweeker · 30th March 2007, 08:18 AM

I have some 6L6s with white powdery getters. They are very quiet, but octal.

Audio_idiot · 30th March 2007, 08:20 AM

Quote:

Originally posted by SY
Quietest in what circuit? Context is everything.

As ground cathode.

Thanks

SY · 30th March 2007, 08:28 AM

OK, that's one bit. Signal level? Source impedance? Load? EQ? Noise weighting? You've barely scratched the surface.

Audio_idiot · 30th March 2007, 08:45 AM

Input signal the usual 1Vrms, Don't know much about noise weight of the input signal... will just have to rely on the meanufacturer's "usual standard".

I recon the PS noise ripple for the tube is about 0.04V but then I've yet to regulate the PS, so lots of room for improvements, I actually tried using noise injection at the cathode for noise cancellation, but since I do not have access to a scope so no maeasurements... This is the rational of asking for a quiet tube so that I could at least identify and sort out my "others" problems...

As for the stage gain, I really is not particular about it, as I'll probly cascade into anothe gain stage. I'll be happy with 10~30x.

I tried 6C45p, then to 6922 then, 6N1P, then 5965 then5842, then.... I'd lost trrack... but the sound is infested with a little hum which is only audioble 2" away, Also, a tat of white noise and which will getting to my nerves when listening in the depth of the night...

I hope these info got my skin scratched:-)

Cheers

Tweeker · 30th March 2007, 03:36 PM

Other things to be checked are heater dress and EMI (such as from transformers or chokes.) If the hum fundamental is 50/60hz and not 100/120 this is an indicator of heater or xfmr related noise.

You may also have dirty power and/or RFI.

30th March 2007, 04:34 AM	#1
Audio_idiot diyAudio Member Join Date: Feb 2006 Location: Malaysia	Quiet Tube Hi guys, I am looking for non-microphonic, quietest 9-pin twin triode tube. As I am frustrated from differentiating tube (internal) noise and other externally generated tube oise. Please kindly recommend Thanks __________________ Audio_Idiot

30th March 2007, 04:54 AM	#2
rcavictim diyAudio Member Join Date: Jun 2004 Location: Cool end of a soldering iron NW of Toronto	Try a 2N6CG7. __________________ I.Q.Test. Have you ever purchased a recreational snowmobile?

30th March 2007, 07:53 AM	#4
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	Quietest in what circuit? Context is everything. __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

30th March 2007, 08:18 AM	#6
Tweeker diyAudio Member Join Date: Dec 2004 Location: Cincinnati, Ohio	I have some 6L6s with white powdery getters. They are very quiet, but octal. __________________ Be sure your foil hat has a good low impedance ground.

30th March 2007, 08:28 AM	#8
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	OK, that's one bit. Signal level? Source impedance? Load? EQ? Noise weighting? You've barely scratched the surface. __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

30th March 2007, 07:42 AM	#3
Geek diyAudio Member Join Date: Sep 2004	I have a box full for JAN GE 5751's that fit that description

30th March 2007, 08:08 AM	#5
oshifis diyAudio Member Join Date: Mar 2004 Location: Budapest, Hungary	I used Tungsram PCC88 for moving coil amplifier, and I could reach 60 dB S/N ratio (A weighted). E88CC is also very good, although a bit less quiet.

30th March 2007, 08:45 AM	#9
Audio_idiot diyAudio Member Join Date: Feb 2006 Location: Malaysia	Input signal the usual 1Vrms, Don't know much about noise weight of the input signal... will just have to rely on the meanufacturer's "usual standard". I recon the PS noise ripple for the tube is about 0.04V but then I've yet to regulate the PS, so lots of room for improvements, I actually tried using noise injection at the cathode for noise cancellation, but since I do not have access to a scope so no maeasurements... This is the rational of asking for a quiet tube so that I could at least identify and sort out my "others" problems... As for the stage gain, I really is not particular about it, as I'll probly cascade into anothe gain stage. I'll be happy with 10~30x. I tried 6C45p, then to 6922 then, 6N1P, then 5965 then5842, then.... I'd lost trrack... but the sound is infested with a little hum which is only audioble 2" away, Also, a tat of white noise and which will getting to my nerves when listening in the depth of the night... I hope these info got my skin scratched:-) Cheers __________________ Audio_Idiot

30th March 2007, 03:36 PM	#10
Tweeker diyAudio Member Join Date: Dec 2004 Location: Cincinnati, Ohio	Other things to be checked are heater dress and EMI (such as from transformers or chokes.) If the hum fundamental is 50/60hz and not 100/120 this is an indicator of heater or xfmr related noise. You may also have dirty power and/or RFI. __________________ Be sure your foil hat has a good low impedance ground.

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