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Thread: 12bh7 valve help

  1. #1
    Join Date: Jun 2014

    Location: Suffolk

    Posts: 383
    I'm John.

    Default 12bh7 valve help

    I currently have an unmarked 12bh7 valve in the line stage of my Croft 25R (which was modded by Glenn to better drive a low impedance s/s power amp) and would like to try a 'better' version of this particular valve.

    I cannot find much info on the web about the relative merits/sound quality of different versions of this particular valve and wondered if anyone here can offer any thoughts/guidance.

    There are a number of different versions of a 17mm Brimar 12bh7 currently on ebay being offered by the same seller with different prices/construction/codes etc but unfortunately, the seller was unable to offer any explanation of the differences between them. Does anyone have any experience of Brimar 12bh7's....?

    Thanks for any help/advice.

    John

  2. #2
    Join Date: Apr 2012

    Location: N E Kent

    Posts: 51,624
    I'm Geoff.

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    My inclination would be to leave it alone if it sounds as it should. If you don't know what brand/spec valve you have, there's no way of telling if an alternative will sound 'better'. Unless of course you buy one.
    It is impossible for anything digital to sound analogue, because it isn't analogue!

  3. #3
    Join Date: Jan 2013

    Location: Birmingham

    Posts: 6,772
    I'm James.

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    Quote Originally Posted by Sondekker View Post
    I currently have an unmarked 12bh7 valve in the line stage of my Croft 25R (which was modded by Glenn to better drive a low impedance s/s power amp) and would like to try a 'better' version of this particular valve.

    I cannot find much info on the web about the relative merits/sound quality of different versions of this particular valve and wondered if anyone here can offer any thoughts/guidance.

    There are a number of different versions of a 17mm Brimar 12bh7 currently on ebay being offered by the same seller with different prices/construction/codes etc but unfortunately, the seller was unable to offer any explanation of the differences between them. Does anyone have any experience of Brimar 12bh7's....?

    Thanks for any help/advice.

    John
    Hi John, I have a NOS RCA 12BH7a in my Croft 25R linestage and have tried a GE NOS 12BH7a but this did not sound quite as good. Never heard a Brimar but I have seen a few fitted in the Croft 25RS linestage, I presume these would be NOS. As with all 12BH7 valves I would suggest those NOS from the 60'or earlier sound the best so I would look into old versions of Brimar valves.

  4. #4
    Join Date: Feb 2008

    Location: South Wales

    Posts: 9,151
    I'm NotTakingLifeTooSeriouslyTheseDays.

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    Hi John,
    I have some original new old stock Black plate Brimar's if you need any.
    Quote Originally Posted by Sondekker View Post
    I currently have an unmarked 12bh7 valve in the line stage of my Croft 25R (which was modded by Glenn to better drive a low impedance s/s power amp) and would like to try a 'better' version of this particular valve.

    I cannot find much info on the web about the relative merits/sound quality of different versions of this particular valve and wondered if anyone here can offer any thoughts/guidance.

    There are a number of different versions of a 17mm Brimar 12bh7 currently on ebay being offered by the same seller with different prices/construction/codes etc but unfortunately, the seller was unable to offer any explanation of the differences between them. Does anyone have any experience of Brimar 12bh7's....?

    Thanks for any help/advice.

    John
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  5. #5
    Join Date: Dec 2008

    Location: Denmark

    Posts: 98
    I'm jan.

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    Hi
    The 12bh7a Tung-sol is very good :-)

  6. #6
    Join Date: Jun 2014

    Location: Suffolk

    Posts: 383
    I'm John.

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    Thanks to those that have been kind enough to respond to my request, any other contributions would still be appreciated.

    I did find one brief review of a small number of different 12bh7 valves and interestingly the reviewer concluded that a Brimar version sounded best to him in his system. I think the fact Jimbo has seen Brimar versions in the 25RS lends further support to one of these being a likely good option to try in my 25R.

    As such, I'd be very interested to hear more from anthonyTD with regard to the Brimars he mentioned.......

    Thanks

    John

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