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  1. #1
    Do What? jrhymeammo's Avatar
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    Tube Replacement Question.

    My tube integrated's been up and running since repair, and it sounds as good as the day it arrived. Now, it's time to play with different tubes. It has stock generic tubes consisting of four KT88s, two 6N6s, and two 6N11.
    I'm thinking about changing pre-amp tubes, and I believe these model numbers are bit misleading.

    I have read that 6N6 are actually 6N6P. If that is correct, they can be replaced with 12BH7/5687. Although 5687 tubes look significantly shorter. Also, I have read that 5687 can be replaced with ECC99/E182CC / 6840 / 6BL7. Are 6N6P tubes used for input stages?

    Also, 6N11 are actually 6N1P, and should be replaced with 6DJ8/6922/ECC83,88. But, my stock tubes read CCCP XII-80 6H23N
    Are 6N11 tubes used for an output stage?

    If you guys can, pleased tell me if information above are correct/false.



    Only replacement I can find for 6N6P is http://www.tubestore.com/ru-6h6p.html. If they can be swaped with other models, my options for 6N6P will increase dramatically.

    I'm also thinking about playing with a different pair of 12AX7 for my phono pre-amp. So far I've narrowed it down to Sovtek 12AX7LPS, Tung-Sol 12AX7 new productions, and Electro Harmonix 12AX7 Gold Pin.

    All of the information really hurts my head, but this gotta be the best part of playing with tube gears.

    Please help me as much as you guys can.

    Thanks.

    -JRA

  2. #2
    Can a crooner get a gig? dean_martin's Avatar
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    Quote Originally Posted by jrhymeammo
    I'm also thinking about playing with a different pair of 12AX7 for my phono pre-amp. So far I've narrowed it down to Sovtek 12AX7LPS, Tung-Sol 12AX7 new productions, and Electro Harmonix 12AX7 Gold Pin.

    All of the information really hurts my head, but this gotta be the best part of playing with tube gears.

    Please help me as much as you guys can.

    Thanks.

    -JRA
    Here are some 12AX7 (and substitute) tubes I've tried:

    RCA 7025 - a little more detail and bass speed than my stock 12AX7As

    12AX7A from a Fender guitar amp made in the 70s. No brand labels, but I'm still researching these to find out who made them - probably RCA

    Ei Elites 12AX7EG gold pins - lots of detail and forward presentation.

    Siemens CV492 - lower output than a regular 12AX7, but has a nice laid back quality.

    JAN5751 by GE- even lower output than the CV492. It's a little too low for my phono/cart combo.

    I have some older Groove Tubes also from a guitar amp that I haven't tried yet. I've read some good things about a new production 12AX7 from Groove Tube that's supposed to be a Telefunken copy or something.

    Tungsram ECC83 (European number for 12AX7) - combines the better qualities of the Ei Elites and Siemens.

    Except for the nos RCA7025s which I got off eBay, the rest I either found or they were given to me. I haven't really shopped for new productions yet.

  3. #3
    Do What? jrhymeammo's Avatar
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    Hi DeanM, thanks for your findings and how is your ChowShep?

    I been to a local tube store and found out that 6H23n are actually 6N23P. I also had no luck with 6H6/(6N6?). The guy at the store showed me 12BH7 and it looked very similar to 6H6/(6N6?) I brought in. He wouldn't sell it to me since we were not certain of compatibility(great guy if you ask me). Does anybody know anything about this topic?

    I purchased a pair of Tung-Sol 12AX7 for my phono-pre. I may post a review after 7-14 days.

    Thanks

  4. #4
    Do What? jrhymeammo's Avatar
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    I have read alot of 6N6 questions/debates. One side claims 12BH7 can be used, but the other says that and 6N6P will not work. Nobody really knows or tried...... I did read someone used 6N6P instead of 6N6 and it blew up his phono-pre. I was hoping Bernd, Flo, Kovacs, Chrisp, Whitese, JT1 Stcav, Y_Suryadi, Unregistered....and a bunch of Cayin owners could help me out.

    Thanks
    -JRA

  5. #5
    If you can't run-walk. Bernd's Avatar
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    Quote Originally Posted by jrhymeammo
    I have read alot of 6N6 questions/debates. One side claims 12BH7 can be used, but the other says that and 6N6P will not work. Nobody really knows or tried...... I did read someone used 6N6P instead of 6N6 and it blew up his phono-pre. I was hoping Bernd, Flo, Kovacs, Chrisp, Whitese, JT1 Stcav, Y_Suryadi, Unregistered....and a bunch of Cayin owners could help me out.

    Thanks
    -JRA
    Hi,
    I was really busy and just saw your query, so apologies for not responding sooner.
    I will try my best.
    Chinese produced audio uses a lot of 6N6 (P) tubes. Cheap and availability the main reasons. The best sounding replacement for this Tube, that I have heard, is the Mullard labeled E182CC. It's a lot better.

    www.machmat.com

    For the 6N11 look into the Svetlana 6N1P it's a very fine tube and long lasting.

    www.watfordvalves.com

    As for the 12AX7s you have a great choice available to you.
    I would always vote for the Telefunken. But they are very expensive and there are a lot of counterfit Teles about.
    The Tungsram is a great sounding tube and available from Upscale Audio.

    As with all tubes, it's the circuit that determines how well the tube will work. As Deano found out. For example my findings with the Siemens CV 492 are different from his. I found them forward sounding.
    Hope this helps.
    Have fun

    Peace

    Bernd
    Last edited by Bernd; 06-25-2006 at 04:19 AM.
    "Let The Earth Bear Witness."

  6. #6
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    Tube Quality

    Quote Originally Posted by jrhymeammo
    My tube integrated's been up and running since repair, and it sounds as good as the day it arrived. Now, it's time to play with different tubes. It has stock generic tubes consisting of four KT88s, two 6N6s, and two 6N11.
    I'm thinking about changing pre-amp tubes, and I believe these model numbers are bit misleading.

    I have read that 6N6 are actually 6N6P. If that is correct, they can be replaced with 12BH7/5687. Although 5687 tubes look significantly shorter. Also, I have read that 5687 can be replaced with ECC99/E182CC / 6840 / 6BL7. Are 6N6P tubes used for input stages?

    Also, 6N11 are actually 6N1P, and should be replaced with 6DJ8/6922/ECC83,88. But, my stock tubes read CCCP XII-80 6H23N
    Are 6N11 tubes used for an output stage?

    If you guys can, pleased tell me if information above are correct/false.



    Only replacement I can find for 6N6P is http://www.tubestore.com/ru-6h6p.html. If they can be swaped with other models, my options for 6N6P will increase dramatically.

    I'm also thinking about playing with a different pair of 12AX7 for my phono pre-amp. So far I've narrowed it down to Sovtek 12AX7LPS, Tung-Sol 12AX7 new productions, and Electro Harmonix 12AX7 Gold Pin.

    All of the information really hurts my head, but this gotta be the best part of playing with tube gears.

    Please help me as much as you guys can.

    Thanks.

    -JRA
    To the best of my knowledge, the tubes with numbers only i.e. 7025 compared to the 12AX7 are the better tubes and have much higher standards. In an amp you can replace a 12AX7 with a 7025 but not vice versa. In other words if your amp is designed for a 7025 you can't go down to a 12AX7. The tube would work but not well. You might get noise or just plain inferior performance. I had heard the numbered tubes only called industrial or hi-fi tubes in the past.

  7. #7
    Do What? jrhymeammo's Avatar
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    Thanks Bernd and ruadmaa, great stuff so far.
    I believe the best way for me to achieve different sound would be to change input tubes. I would need to perform more research on E182CC and 12BH7. As for 7025, this is great to know for future reference. Are 7025 military tubes for 12AX7?

    Thanks

    -JRA

  8. #8
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    Number Only Tubes

    Quote Originally Posted by jrhymeammo
    Thanks Bernd and ruadmaa, great stuff so far.
    I believe the best way for me to achieve different sound would be to change input tubes. I would need to perform more research on E182CC and 12BH7. As for 7025, this is great to know for future reference. Are 7025 military tubes for 12AX7?

    Thanks

    -JRA
    An old RCA receiving tube manual that I have lists numberd tubes as "Industrial Tubes". There is no mention of military design/application.

  9. #9
    Up & Coming Bottlehead jt1stcav's Avatar
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    Sorry for not responding sooner...I don't frequent this forum all that much.

    I'm still basically a tube noob myself, only having experience with tubes I'm familiar with (valves on my amp and preamp).

    When I did need to look up equivalents for my amp's driver tubes, this site was more than helpful for me, so I'm recommending it to you. Hope this helps:

    http://www.valve-museum.org/

    Good luck in your quest!
    ~ Jim Tidwell ~



    "Uh, jazz flute is for little fairy boys." - Veronica Corningstone

  10. #10
    Do What? jrhymeammo's Avatar
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    I decided to post a reply here for those who might care in a future.
    I received 2 pairs of 6N6-Ts made by Shuguang from this company in France.

    www.audiotriodes.com

    I should've order at least 3 pairs. Oh well. I should at least have 1000 hrs left on stock tubes, and maybe 5000+ on those 2 pairs.
    If every goes right I'll be set for more than 5 years.

    Happy Glowing.
    JRA

  11. #11
    AR Newbie Registered Member
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    Exclamation

    Quote Originally Posted by jrhymeammo
    My tube integrated's been up and running since repair, and it sounds as good as the day it arrived. Now, it's time to play with different tubes. It has stock generic tubes consisting of four KT88s, two 6N6s, and two 6N11.
    I'm thinking about changing pre-amp tubes, and I believe these model numbers are bit misleading.

    I have read that 6N6 are actually 6N6P. If that is correct, they can be replaced with 12BH7/5687. Although 5687 tubes look significantly shorter. Also, I have read that 5687 can be replaced with ECC99/E182CC / 6840 / 6BL7. Are 6N6P tubes used for input stages?

    Also, 6N11 are actually 6N1P, and should be replaced with 6DJ8/6922/ECC83,88. But, my stock tubes read CCCP XII-80 6H23N
    Are 6N11 tubes used for an output stage?

    If you guys can, pleased tell me if information above are correct/false.



    Only replacement I can find for 6N6P is http://www.tubestore.com/ru-6h6p.html. If they can be swaped with other models, my options for 6N6P will increase dramatically.

    I'm also thinking about playing with a different pair of 12AX7 for my phono pre-amp. So far I've narrowed it down to Sovtek 12AX7LPS, Tung-Sol 12AX7 new productions, and Electro Harmonix 12AX7 Gold Pin.

    All of the information really hurts my head, but this gotta be the best part of playing with tube gears.

    Please help me as much as you guys can.

    Thanks.

    -JRA
    my 2 cents:

    If you stop your choose at 6N1P (you or some other who read this forum). Look at 6n1p-ev, "EV" symbols mean, that tube have high mechanical strength and reliability, increased durability (5000 hours or more)

  12. #12
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    Try this link for a comprehensive listing of tubes:

    http://tdsl.duncanamps.com/

    There are two general factors in tube replacement (beyond having the correct pin base.)

    The bigger factor is internal wiring - do two tubes have the same pin-out for the internal connections? A tube that has the heaters, plates, grids, etc. hooked to different pins simply will not work unless you rewire the tube socket.

    However, even if the pin-out is the same, the other factor is the electrical characteristics need to be fairly similar for a tube substitute to work. You may or may not be able to substitute a tube if gains, current draw, circuit voltages, etc. are different.

    As an example, I recently rebuilt a Dynaco ST-70 and used 6L6GC outputs instead of EL34s. I had to replace the 10K bias pot with a 25K unit in order to provide enough adjustment to bias the amp.

  13. #13
    Do What? jrhymeammo's Avatar
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    Thanks for the posts,

    Wow, a thread from over 3 years ago.
    Reading my first post really shows how much of a Tube-Nube I was.

    Though I still own the amp, I no longer use it. Also, I have resolve the problem by importing stated tubes from France.
    I had unpacked it 3 nights ago, and had thought about replacing some critical parts instead of selling it (my desoldering skills are improving... slowly).

    JRA - Still a Tube Nube, just less afraid.

  14. #14
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    I replaced my Chinese 6N1 tubes with Russian 6N1p-EV. The Russians on ebay are dirt cheap and much better. According to one Russian ebay merchant the Chinese 6N1 is a cheap copy of the Russian 6N1p. I have two Chinese tube amps and a Chinese tubed CDP. First thing I did with each piece was to get rid of those lousy Chinese tubes.

    Russian Migs still use vacuum tubes which are less vulnerable to a nuclear strike than transistors.

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