The Dynaco Tube Audio Forum

Dedicated to the restoration and preservation of all original Dynaco tube audio equipment - Customer support for Tubes4hifi VTA tube amp and preamp kits and all products

    changing tubes


    Posts : 3
    Join date : 2010-01-10

    changing tubes Empty changing tubes

    Post by Varlagger on Thu Jan 14, 2010 7:39 am

    swapped out existing el34 in my st70 with a new matched quad of shunguang sp. EL34-B.
    Had a difficult time seating the tubes next to the xfmrs. Had to rock and roll them around quite a bit to seat them properly.The front ones went in very easy? The tube pins seemed slightly splayed outward and pin tips seemed a little rough compared to the tubes that came out.Can the tube pins be lightly dressed with emery sp.cloth and dressed with a contact enhancer?Also,is it appropriate to bias the EL34-B a little lower to start,then slowly raise bias as tubes burn in over time? Thanks Varlagger

    Posts : 91
    Join date : 2009-04-17

    changing tubes Empty Re: changing tubes

    Post by Bugs on Thu Jan 14, 2010 10:20 am

    I'm guessing that your EL 34Bs are Tung-Sols. I have two quads of them and have had to rock them some what to get them in, but my sockets are newly replaced.

    Try swapping the tubes front to back and see if the problem follows the tube. If it does the tube is the problem, if not. then it is the socket.

    The Tung-Sol EL 34B is a very nice sounding tube.


    Posts : 18
    Join date : 2009-01-18
    Age : 58
    Location : Richfield (S. Minneapolis) Minnesota

    changing tubes Empty Re: changing tubes

    Post by Tazsmonn on Fri Jan 15, 2010 7:31 pm

    Yes you could dress pins.

    Sponsored content

    changing tubes Empty Re: changing tubes

    Post by Sponsored content

      Current date/time is Mon May 25, 2020 9:21 pm