Author Topic: Question regarding 6J5 and 6SN7 tube usage  (Read 559 times)

Offline Response Audio

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Question regarding 6J5 and 6SN7 tube usage
« on: July 04, 2022, 10:00:19 AM »
Greetings and Happy 4th.
I am building a custom amplifier for my own personal use. It is design with one 6J5 per channel. My question is about installing a 6SN7 into these positions. I have heard of a few different techniques on what to do with the unused side of the 6SN7 when used in a 6J5 socket.
For those who have done this, what have you done with the unused side. I know most of you will simply say, “Just stick with the 6J5” but I want to experiment with it both ways and try different tubes.
What is your preferred method of dealing with the unused half of a 6SN7.
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Offline P.I.

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Re: Question regarding 6J5 and 6SN7 tube usage
« Reply #1 on: July 04, 2022, 10:27:09 PM »
Greetings and Happy 4th.
I am building a custom amplifier for my own personal use. It is design with one 6J5 per channel. My question is about installing a 6SN7 into these positions. I have heard of a few different techniques on what to do with the unused side of the 6SN7 when used in a 6J5 socket.
For those who have done this, what have you done with the unused side. I know most of you will simply say, “Just stick with the 6J5” but I want to experiment with it both ways and try different tubes.
What is your preferred method of dealing with the unused half of a 6SN7.
Wire one channel using the first section and the other channel using the second section.  That way you can get ~ twice the life out of a matched pair of 6SN7.  One triode dies, swap the tubes.
"A man with an experience is never at the mercy of a man with an argument." - Hilmar von Campe

Offline Response Audio

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Re: Question regarding 6J5 and 6SN7 tube usage
« Reply #2 on: July 05, 2022, 06:40:13 AM »
Thanks Dave. While I will primarily be using 6J5’s, that is the plan for the 6SN7.
I’m am just wondering what others that do this do with the unused half of the triode that is not in the circuit. Some will ground the unused half while other simply leave them alone.
I know leaving the other half alone can still effect the unused half of the triode.
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Offline P.I.

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Re: Question regarding 6J5 and 6SN7 tube usage
« Reply #3 on: July 05, 2022, 11:39:16 AM »
Thanks Dave. While I will primarily be using 6J5’s, that is the plan for the 6SN7.
I’m am just wondering what others that do this do with the unused half of the triode that is not in the circuit. Some will ground the unused half while other simply leave them alone.
I know leaving the other half alone can still effect the unused half of the triode.
Grounding the unused side is the best, methinks.
"A man with an experience is never at the mercy of a man with an argument." - Hilmar von Campe

Offline steve

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Re: Question regarding 6J5 and 6SN7 tube usage
« Reply #4 on: July 05, 2022, 08:37:05 PM »
Greetings and Happy 4th.
I am building a custom amplifier for my own personal use. It is design with one 6J5 per channel. My question is about installing a 6SN7 into these positions. I have heard of a few different techniques on what to do with the unused side of the 6SN7 when used in a 6J5 socket.
For those who have done this, what have you done with the unused side. I know most of you will simply say, “Just stick with the 6J5” but I want to experiment with it both ways and try different tubes.
What is your preferred method of dealing with the unused half of a 6SN7.

I was wondering if you are re wiring the socket for each tube, an adapter, or "toggle" type switching of pins?

cheers

steve
« Last Edit: July 07, 2022, 08:51:56 AM by steve »
Steve Sammet (Owner, Designer, Electron Eng, SAS Audio Labs, Ret)
SAS "V" 39pf/m 6N copper ICs,
SAS Test Phono Stage
Accutex 320 iii STR Mov Iron Cart
SAS 11A Perfect Tube Preamp
SAS 25 W Reference Triode/UL Monoblocks
2 way Floor standing Test Speakers

Offline Response Audio

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Re: Question regarding 6J5 and 6SN7 tube usage
« Reply #5 on: July 06, 2022, 05:52:12 AM »
Hi Steve. The amp will use on 6J5 per channel and each socket will be wired for a 6J5. I simply want to be able to drop in a 6SN7 in each socket using only half the tube.
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Purity Audio Design www.PurityAudioDesign.com
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Offline tmazz

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Re: Question regarding 6J5 and 6SN7 tube usage
« Reply #6 on: July 06, 2022, 09:52:27 PM »
But based on the diagrams that Steve just provided you would not be able to just swap out a 6sn7 for a 6j5 becasue the pin outs on the 6j5 do not correspond the the pin assignments on either half of the 6sn7. For example Pin 2 is a cathode connection of the 6j5 but the plate connection for triode 2 in a 6sn7.

Although they both us the same size octal socket the two tubes are far from pin compatible.
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Offline Response Audio

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Re: Question regarding 6J5 and 6SN7 tube usage
« Reply #7 on: July 07, 2022, 08:12:40 AM »
Thanks guys for the responses….My apologies. I just figured out why this post is so confusing. Nothing more than a brain fart on my part in the first post.  :duh I left out the most important part. Im in process of making 2 tube adapters for the proper pin out change of 6J5 to the 6SN7. I’ve made several in the past to go from 6SN7 to 12AU7.
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Raven Audio - www.RavenAudio.com
Purity Audio Design www.PurityAudioDesign.com
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Offline tmazz

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Re: Question regarding 6J5 and 6SN7 tube usage
« Reply #8 on: July 07, 2022, 10:10:06 AM »
That would do it.  8)
Remember, it's all about the music........

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Offline P.I.

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Re: Question regarding 6J5 and 6SN7 tube usage
« Reply #9 on: July 07, 2022, 11:30:10 AM »
Thanks guys for the responses….My apologies. I just figured out why this post is so confusing. Nothing more than a brain fart on my part in the first post.  :duh I left out the most important part. Im in process of making 2 tube adapters for the proper pin out change of 6J5 to the 6SN7. I’ve made several in the past to go from 6SN7 to 12AU7.
Oh.  Gotcha!
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Offline steve

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Re: Question regarding 6J5 and 6SN7 tube usage
« Reply #10 on: August 07, 2022, 10:52:33 AM »
For newbies,

For someone who wishes to create their own adapter, or switching for multiple tube types,
it is very difficult to design such without affecting the sonic qualities of the music.

Depending upon how critical one wishes to listen and compare, one must consider the extra
number of solder connections/terminations, type of solder, if used, extra pin connections and
materials involved, wire type and purity used, materials in general in switches; all will  influence
the sonic quality and signal degradation. 

A poor quality adapter or switching tube pin assignment will give a false impression, or misleading
sonic difference between different tube types that may not be accurate.

cheers

steve
« Last Edit: August 07, 2022, 11:06:46 AM by steve »
Steve Sammet (Owner, Designer, Electron Eng, SAS Audio Labs, Ret)
SAS "V" 39pf/m 6N copper ICs,
SAS Test Phono Stage
Accutex 320 iii STR Mov Iron Cart
SAS 11A Perfect Tube Preamp
SAS 25 W Reference Triode/UL Monoblocks
2 way Floor standing Test Speakers

Offline Response Audio

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Re: Question regarding 6J5 and 6SN7 tube usage
« Reply #11 on: August 07, 2022, 01:21:32 PM »
You are absolutely correct Steve. Thank you for bringing this up. I don’t want to imply that using tube adapters is a proper way of doing things. When I do it, it is usually for testing purposes. The final design does not use adapters and always re-tested after using the proper tube socket for tube used.
I would never recommend a newbie attempt  to make their own tube adapters. One slight oversight and you chance damaging your build/product and possible bodily harm.
Design Engineer
Raven Audio - www.RavenAudio.com
Purity Audio Design www.PurityAudioDesign.com
Purity Foundation Buffer, Geshelli J2 DAC, Raven Osprey, Custom 98dB tower speakers, Sony SACD Player, Raven Cables, Musica Bella Cables, Levan Audio Rack

Offline tmazz

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Re: Question regarding 6J5 and 6SN7 tube usage
« Reply #12 on: August 07, 2022, 04:22:24 PM »
Oh yeah. Tube circuits do not use a simple 5v B+ rail.  :shock:

Get something wrong and things tend to go boom.
Remember, it's all about the music........

• Nola Boxers
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• McIntosh MC 275
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