Thanks again, Garey - yeah I begin to wonder when a counter isn't at least toggling the last digit :) Great news, as I can finally get the R-4A back together so it will be off the floor of the shack.
I was sort of drawing the same conclusion that in mixer service there wouldn't be a lot of difference. In fact, I put a used 6HS6 in there anyway, figuring that performance could be degraded, and upon re-touching the trimmers last night, there wasn't much change needed to peak the signals. I did find another issue, but I'll save it for a separate post so folks can find it in the archives easier. 73, Steve, W1ES/4 in rainy NC. -----Original Message----- >From: Garey Barrell <k4...@mindspring.com> >Sent: Sep 22, 2011 2:42 PM >To: Steve Wedge <w1es1...@earthlink.net> >Cc: drakelist@zerobeat.net >Subject: Re: [Drakelist] R-4B V8: 6HS6 vs 6AU6 > >Steve - > >Your PTO is on the way back. I finally got the time to pack and ship it. >It's been sitting on the >bench, running for the last week or so with the counter on it. It stays >within +/- 100 Hz from day >to day, just sitting in the open. I turned the counter so I could see it from >my desk and would >just look up at it to check from time to time. When the AC kicks on, it moves >a little more, but >that's not going to happen mounted inside the receiver! We had a couple of >cool days when the AC >didn't kick on all day, and the frequency just sat there. > >I checked it several times yesterday, and about the third time I looked up it >dawned on me that it >hadn't moved a single Hz!! Hmmmmmm. Not likely. So I looked and the GATE >light on the counter >wasn't flashing........ So I hit the reset and it went to 0?!?!? I touched >the scope probe to it >and still full amplitude. So I switched the counter from low range to high >range and back on the >counter and it started counting again.......... > >The 6AU6 is an ok sub in the PreMixer, but is only about 1/2 the Gm of the >6HS6. I think there is >plenty of gain, so probably no big deal, but possibly less LO output, >degrading performance. The >6AH6 is a much better choice for a reasonably priced sub, with even higher Gm. > >It's not a problem in the R-4A, but the 'HS and 'AH are 0.45A filament, vs >0.3A for the 'AU may be a >problem in a series arrangement. > >73, Garey - K4OAH >Glen Allen, VA > >Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line >and TR-4/C Service Supplement CDs ><www.k4oah.com> > > >Steve Wedge wrote: >> I know the 6HS6 and 6AU6 have the same base and are actually listed as >> substitutes for each >> other. I also know the 6HS6 has higher Gm. >> I noticed, when putting this R-4B back together, that the PO put a 6AU6 in >> V8. The receiver seems >> to work fine, so how critical is it using a 6AU6 in V8 (the premixer)? _______________________________________________ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
