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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

    Stereo 35 rustling and smoke show


    Posts : 845
    Join date : 2008-12-05

    Stereo 35 rustling and smoke show Empty Stereo 35 rustling and smoke show

    Post by PeterCapo on Tue Sep 27, 2011 2:10 pm

    A few weeks ago, some rustling noises got louder out of the left channel. After a while, it went nuclear and incinerated the 1.3k resistor, R3, off of the driver's cathode at pin 8 (section one of the tube, according to an old GE datasheet I referenced).

    I replaced the burned resistor. After wrestling with the rustling for several days, I finally tried swapping the 18pf capacitor, C6 – and the rustling switched channels. Apparently it has an intermittent short that sent some serious DC from the OPT primary back to R3 and fried it. It's a new mica capacitor, too, so I guess defective parts out of the bin are something to consider. In any case, this was a bugger to isolate, and I thought I would pass it on. Great sounding little amp, though, I'll tell ya...

      Current date/time is Mon Jul 13, 2020 4:55 pm