Yes, the 2A and 2B use 8BN8's. Garey (who else?) explained it on this list at http://www.mail-archive.com/drakelist@zerobeat.net/msg06662.html
Garey, we really need you. Glad you're getting better. Please let us know when you can take orders for your CDs. 73, Bob WW3QB --- On Sat, 9/5/09, Tom NØJMY <n0...@hayseedhamfest.com> wrote: From: Tom NØJMY <n0...@hayseedhamfest.com> Subject: [Drakelist] About those " right tubes" To: "Walker" <g...@worldnet.att.net> Cc: drakelist@zerobeat.net Date: Saturday, September 5, 2009, 9:14 PM I ran into roughly the same situation a few years back. I had a 2-C that was a real dog. It turned out that the manual said 12BZ6, the tube was a 12BZ6, but the chassis was lettered 6BZ6. So I measured the heater voltage at the socket just to be sure - 6.3 VAC. Changed out the tube to a 6-volt unit and what a difference that made, hi! On a little different subject, I was thinking that someone told me that Drake had some units that were designed to use an 8-volt tube with 6 volts to the heater, for some arcane reason. Am I imagining this? Vy 73, Tom Walker wrote: > I have a TR-4, 1968 manufacture date, serial number 28124. It has worked well > for years, with the last few being dormant as my vertical took a hit a few > winters ago with icing. I've replaced the vertical, and I'm trying to re-tube > the unit. Here is where the confusion arises: > The chassis lettering and schematic for tubes V4, V5, V11 and both agree and >are respectively: 6EJ7, 6BA6, 6BZ6. > Note: the schematic has V5 and V11 with a hand lettered "6" in front of 6BA6 >and 6BZ6 versus all other tubes which have stencil guided lettering. > The Manual's Voltage Reference chart and Tube List for V4, V5 and V11 are: >6EJ7, 12BA6, 12BZ6 > The Manual's Block Diagram shows V4 as 6HS6 > I'm not sure what's supposed to be right, though I have a tendency to >believe the chassis lettering and schematic. The manual is internally >inconsistent, and doesn't agree with the physical hardware or schematic. I >probably can take out V5 and V11 and measure the filament voltage present to >see if it really is set up for a 6 or 12 volt tube in those sockets. > I found some correspondence between the original owner, whom I purchased the >unit from, and the factory regarding a technical problem. The factory rep >wasn't sure in solving a problem whether the former owner needed a 6BZ6 or a >12BZ6 so he sent him one of each. Apparently the factory didn't know either! > Was there some changeover for different serial number ranges, between >various tube types or what, and what is the best way to tell which tubes >really belong in the circuits? > Thanks for pointing me toward a resource, if you know one, to help get some >answers. > Phil WA2CLX > > > ------------------------------------------------------------------------ > > _______________________________________________ > Drakelist mailing list > Drakelist@zerobeat.net > http://mailman.zerobeat.net/mailman/listinfo/drakelist _______________________________________________ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
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