Another one for Steve Wedge: 2B or not 2B, that is the question - Shakespeare.
Nigel Patterson On Sat, Nov 12, 2011 at 5:00 PM, <[email protected]> wrote: > Send Drakelist mailing list submissions to > [email protected] > > To subscribe or unsubscribe via the World Wide Web, visit > http://mailman.zerobeat.net/mailman/listinfo/drakelist > or, via email, send a message with subject or body 'help' to > [email protected] > > You can reach the person managing the list at > [email protected] > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Drakelist digest..." > > > Today's Topics: > > 1. R-4B is "under contract" (Steve Wedge) > 2. Bias Adjustment on TR4CW (Michael A. Kelly) > 3. Re: Bias Adjustment on TR4CW (John Brown) > 4. Re: Bias Adjustment on TR4CW (Ron) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Fri, 11 Nov 2011 20:19:57 -0500 > From: "Steve Wedge" <[email protected]> > To: "k4eg" <[email protected]>, "Drake List" > <[email protected]> > Subject: [Drakelist] R-4B is "under contract" > Message-ID: <20A961ED89CA420DABB044FBA678B8DF@Shack7> > Content-Type: text/plain; charset="iso-8859-1" > > My "demodded" Drake R-4B is sold pending payment. > > I'll be looking for more restoration projects at Benson (NC, Nov 20th)! I > seem to be settling into working on Drakes and this burden is fitting to me > well. I'm considering my "hobby-job" to be finding more tired Drake rigs > and rejuvenating them. I'm learning even more as I go, and what I'm making > allows me to buy even more Drakes to bring back from the dead. > > I've always enjoyed working on Drake gear: there are some aspects that can > be challenging, but overall, it was well-designed and much more designed > for serviceability than many other radios of its time. My shack has felt > much more a "home" since I've set aside space for a set of Twins. > > Steve Wedge, W1ES/4 > > To be is to do - Socrates > To do is to be - Plato > Do be do be do. - Sinatra > > All my computers have my signature with various pearls of wisdom appended > thereto. > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://mailman.zerobeat.net/pipermail/drakelist/attachments/20111111/0c41b361/attachment-0001.html > > > > ------------------------------ > > Message: 2 > Date: Fri, 11 Nov 2011 21:53:55 -0500 > From: "Michael A. Kelly" <[email protected]> > To: [email protected] > Subject: [Drakelist] Bias Adjustment on TR4CW > Message-ID: > <CAJWwtAAP=ykqfvaxb8zj41qtug6qwdf75owtyzcynqsd+1k...@mail.gmail.com > > > Content-Type: text/plain; charset=ISO-8859-1 > > Question 1: > > Would tube life be extended if I ran my TR4Cw at 108-110 Volts AC > instead of 120VAC? (All of the 21 tubes, not just the transmitting > tubes?) I have access to a variac and could do it easily. Has > anyone else done this? Obviously output would suffer a bit, but I > typically run 90-100 watts maximum anyway. Aside from less possible > total power output, is there a downside here? > > Question 2: > > When you adjust the PA Bias to 0.1 what exactly is that doing, > decreasing the voltage similar to a variac? Does it affect all tubes, > or just the finals? If so, again, why not turn it down to say 0.009 > instead of 0.1 and again extend tube life? > > Thanks, > > Michael Kelly N4MAK > > > > ------------------------------ > > Message: 3 > Date: Sat, 12 Nov 2011 15:31:26 +1100 > From: "John Brown" <[email protected]> > To: "'Michael A. Kelly'" <[email protected]>, > <[email protected]> > Subject: Re: [Drakelist] Bias Adjustment on TR4CW > Message-ID: <[email protected]> > Content-Type: text/plain; charset="us-ascii" > > Reducing the mains input probably wouldn't make any difference to tube > life. > Regarding the bias setting, changing this would only shift the class of > operating the finals a tad from the design spec if any. Can't see much to > be > gained from doing either. Why not just use the rig and enjoy it? > JB > > -----Original Message----- > From: [email protected] [mailto: > [email protected]] > On Behalf Of Michael A. Kelly > Sent: Saturday, 12 November 2011 1:54 PM > To: [email protected] > Subject: [Drakelist] Bias Adjustment on TR4CW > > Question 1: > > Would tube life be extended if I ran my TR4Cw at 108-110 Volts AC > instead of 120VAC? (All of the 21 tubes, not just the transmitting > tubes?) I have access to a variac and could do it easily. Has > anyone else done this? Obviously output would suffer a bit, but I > typically run 90-100 watts maximum anyway. Aside from less possible > total power output, is there a downside here? > > Question 2: > > When you adjust the PA Bias to 0.1 what exactly is that doing, > decreasing the voltage similar to a variac? Does it affect all tubes, > or just the finals? If so, again, why not turn it down to say 0.009 > instead of 0.1 and again extend tube life? > > Thanks, > > Michael Kelly N4MAK > > _______________________________________________ > Drakelist mailing list > [email protected] > http://mailman.zerobeat.net/mailman/listinfo/drakelist > > > > > ------------------------------ > > Message: 4 > Date: Sat, 12 Nov 2011 04:28:44 -0800 (PST) > From: Ron <[email protected]> > To: [email protected], "Michael A. Kelly" <[email protected]> > Subject: Re: [Drakelist] Bias Adjustment on TR4CW > Message-ID: > <[email protected]> > Content-Type: text/plain; charset="iso-8859-1" > > Q1: It might help some, but it could just as well hurt the tubes.? All > tubes are rated for a specific filament voltage.? All voltage variations, > both above and below, specified voltage cause issues.? It is my > understanding that indirectly heated tube (as are in all the Drakes) are > more tolerant of slight voltage variations.? Other here have more > background and will hopefully comment. > > Q2:? The bias you adjust on the Drakes is just on the finals. It is > adjusted to make the final tubes amplify in a linear fashion.? Bias is a > compromise, more bias generally makes the amplification more linear (less > distortion) but less efficient, while less bias make the amplification more > efficient and less linear (more distortion).? In the case of the Drakes, it > is important to adjust the bias to the value that Drake engineered.? > Anything outside of that value will either cause more "splatter" > (distortion) or shorten tube life.? > > 73, > Ron WD8SBB > > > --- On Fri, 11/11/11, Michael A. Kelly <[email protected]> wrote: > > From: Michael A. Kelly <[email protected]> > Subject: [Drakelist] Bias Adjustment on TR4CW > To: [email protected] > Date: Friday, November 11, 2011, 9:53 PM > > Question 1: > > Would tube life be extended if I ran my TR4Cw at 108-110 Volts AC > instead of 120VAC? (All of the 21 tubes, not just the transmitting > tubes?)? I have access to a? variac and could do it easily.? Has > anyone else done this?? Obviously output would suffer a bit, but I > typically run 90-100 watts maximum anyway.? Aside from less possible > total power output, is there a downside here? > > Question 2: > > When you adjust the PA Bias to 0.1 what exactly is that doing, > decreasing the voltage similar to a variac? Does it affect all tubes, > or just the finals?? If so, again, why not turn it down to say 0.009 > instead of 0.1 and again extend tube life? > > Thanks, > > Michael Kelly N4MAK > > _______________________________________________ > Drakelist mailing list > [email protected] > http://mailman.zerobeat.net/mailman/listinfo/drakelist > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://mailman.zerobeat.net/pipermail/drakelist/attachments/20111112/75cccdae/attachment-0001.html > > > > ------------------------------ > > _______________________________________________ > Drakelist mailing list > [email protected] > http://mailman.zerobeat.net/mailman/listinfo/drakelist > > > End of Drakelist Digest, Vol 41, Issue 20 > ***************************************** >
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