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    alternate tubes EH 6CA7 6GH8

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    dmagazz

    Posts : 137
    Join date : 2018-06-20
    Age : 50
    Location : new fairf, ct

    alternate tubes EH 6CA7 6GH8

    Post by dmagazz on Sat Jun 23, 2018 4:52 pm

    are  6CA7 tubes a "drop - bios n go" tube? upgrade?

    also, what of the 6GH8. good less expensive sub with adaptors for the 7199?
    what should i expect using any of these?
    anyone?
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    PeterCapo

    Posts : 541
    Join date : 2008-12-05

    Re: alternate tubes EH 6CA7 6GH8

    Post by PeterCapo on Sat Jun 23, 2018 7:13 pm

    dmagazz wrote:...anyone?

    Electro Harmonix 6CA7 should be a good choice - a lot of positive comments around online. Yes, compatible with Stereo 70. I suggest a closely matched quad from McShane Design. Ask Jim about a new Gold Lion GZ34 while you're at it.

    6GH8 should be okay as long as they are good samples. I suggest same brand for both in the pair - same date code may also be a plus. Remember to support the PC board from underneath when installing the adapters and then the tubes. BTW, the 7199 pair you now have may be fine and may still last a long time.
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    dmagazz

    Posts : 137
    Join date : 2018-06-20
    Age : 50
    Location : new fairf, ct

    Re: alternate tubes EH 6CA7 6GH8

    Post by dmagazz on Sat Jun 23, 2018 10:49 pm

    BTW, the 7199 pair you now have may be fine and may still last a long time.

    well thats good to know. i also hear they are getting scarce, i wouldnt be suprised if someone didnt get on the ball with that in the near future though.

    Electro Harmonix 6CA7 should be a good choice
    and
    6GH8 should be okay as long as they are good samples


    i was looking at them on the tubes for hifi. and considering getting these and storing mine
    i made a little mistake(of sorts) today with mine though..
    i cleaned up the amp, got out the alcohol,Q-tips,paper towels,an old toothbrush,and flat tip dental pick and reset the pin connectors in the sockets.
    ill post the results Smile befor and after..
    but what i did wrong was i almost wiped off the dynaco logo's on the tubes wile wiping them. i was very delicate with them, but the first one i did i realized i wiped it away, the second one i was nicer to but it got unreadable a bit, the other 2 i stayed away from the print. as well as the recto tube and 7199's. also oooof.. the power tranny.. geeze. didnt expect it to turn to tar, thought it would stay firm cleaning it. but no, and the print smudged on that.
    all in all though. it came out pretty good i think.




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    PeterCapo

    Posts : 541
    Join date : 2008-12-05

    Re: alternate tubes EH 6CA7 6GH8

    Post by PeterCapo on Sun Jun 24, 2018 12:21 pm

    dmagazz wrote:...didnt expect it to turn to tar...

    Some of the power transformers were originally dipped in tar.  Looks like yours was.

    I wouldn't use alcohol on the end bells of the two output transformers - try regular car wax (not polish) on those.

    As far as your 7199s, if the voltage readings everywhere else line up with the chart in the manual, and if the amp sounds good and clean, then the 7199s should be okay to use.
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    dmagazz

    Posts : 137
    Join date : 2018-06-20
    Age : 50
    Location : new fairf, ct

    Re: alternate tubes EH 6CA7 6GH8

    Post by dmagazz on Sun Jun 24, 2018 3:58 pm

    already done cleanin pete,those other end bells were just painted steel.i got them with a little furniture wax.
    only the power trans was tar'ed.
    im going to check the voltages wednesday when i get my diode kit to change out the selenium rectifier for a diode,ill better determine then if anything else has to be done, like tube bios resistor change/add.or change any other resistors that might be suspect.
    i expect everything to be ok though, considering the shape its in.

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