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Scott 16A
#14

Well, the 16A started to produce some unwanted noises and symptoms I didn't like after playing beautifully for several months.  I decided it was time to dig into the Tobe and Sangamo  molded caps.  I could not find even 1 Tobe cap that measured anything reasonable on my  fluke DMM.  Every Sangamo measured fine (perhaps the Sangamo caps are all mica's???).  I realize that the Fluke is not a perfect cap tester, but my replacement caps all measured fine with this meter.  Anyway, they are replaced, the radio re-aligned ( and it did re-align better than before), and it plays again.  Now we'll see if it holds up.

I have a question for the 6L6 aficionados out there.  The push pull is self biased using a 210 ohm cathode resistor, 402 volt plate voltage, 277 volt screen voltage.  This yields a -20 volt grid voltage with 95 ma idle current for both tubes.  Most data sheets on the 6L6 talk about a grid bias more like -30 volts. These are new Solvtek tubes that I've had in my inventory for maybe 25 years. Is my idle current within reason or should I increase the size of the cathode resistor to shut the tubes down a bit? Perhaps these cheap Solvtek tubes have a bit different characteristics than original 6L6's??

Thanks for your input!

Rob


Messages In This Thread
Scott 16A - by rfeenstra - 01-28-2018, 02:03 PM
RE: Scott 16A - by Brad Winder - 01-29-2018, 09:46 PM
RE: Scott 16A - by morzh - 01-30-2018, 09:20 AM
RE: Scott 16A - by rfeenstra - 01-30-2018, 05:39 PM
RE: Scott 16A - by Electrothaumaturgist - 01-30-2018, 06:37 PM
RE: Scott 16A - by rfeenstra - 01-30-2018, 07:31 PM
RE: Scott 16A - by rfeenstra - 03-03-2018, 02:43 PM
RE: Scott 16A - by Phlogiston - 03-03-2018, 04:16 PM
RE: Scott 16A - by rfeenstra - 03-03-2018, 07:51 PM
RE: Scott 16A - by Phlogiston - 03-03-2018, 08:02 PM
RE: Scott 16A - by rfeenstra - 03-03-2018, 08:21 PM
RE: Scott 16A - by rfeenstra - 03-03-2018, 10:52 PM
RE: Scott 16A - by Phlogiston - 03-04-2018, 09:41 AM
RE: Scott 16A - by rfeenstra - 05-07-2018, 11:21 PM
RE: Scott 16A - by morzh - 05-08-2018, 07:58 AM
RE: Scott 16A - by Arran - 05-09-2018, 04:05 AM
RE: Scott 16A - by rfeenstra - 05-09-2018, 07:48 AM
RE: Scott 16A - by morzh - 05-09-2018, 08:49 AM
RE: Scott 16A - by Phlogiston - 05-09-2018, 09:02 AM



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