My bad. Why did they use six different components? Does each R/C "set" alter the phase a set amount?
W1ES -----Original Message----- >From: Garey Barrell <[email protected]> >Sent: Nov 2, 2011 10:27 AM >To: Steve Wedge <[email protected]> >Cc: Mark Nace <[email protected]>, "Michael A. Kelly" <[email protected]>, >[email protected] >Subject: Re: [Drakelist] Side Tone Adjustment for TR4CW Possible? > >Steve - > >Nope... The large section of the filter cap is additional decoupling >of the B+ for the low level audio stages, (V9), and the small section is >the cathode bypass for the VOX Amp, (V10a). C110, 111 and 112, along >with R97, R98 and R99 form a phase shift network at the frequency of >oscillation. There are plenty of formulas for calculating values for >any reasonable frequency on the internet. ALL six pieces form the >network, you can't just change one or two! :-) There is a limit to >what you can do with the T-4X, because the audio tone is applied to the >MIC input for TUNE mode (whistling into the microphone) and so has to be >within the audio passband of the transmit filters. The tone is also >used to drive the VOX, detected and integrated to control the 6EV7. > >The TR-4 series is a little different. It doesn't use the tone for >TUNE, only for SIDETONE and VOX. It is generated in the same way, C180, >C181 and C182, along with R126, 127 and 128. > >-- >73, Garey - K4OAH >St Charles, IL > >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've thought about doing this in my Twins. Now that I've got a few extra >> transmitters, this might be a good time to experiment. On the T-4X, I >> believe half the can electrolytic is part of the sidetone r-c circuit. >> >> Steve, W1ES/4 >> >> -----Original Message----- >>> From: Mark Nace<[email protected]> >>> Sent: Nov 1, 2011 10:14 PM >>> To: "Michael A. Kelly"<[email protected]>,[email protected] >>> Subject: Re: [Drakelist] Side Tone Adjustment for TR4CW Possible? >>> >>> Mike, >>> I think it's an audio phase-shift oscillator, so guess you would need to >>> change >>> some of the R-C values to get a lower freq. >>> >>> Others will give better thoughts I am sure. >>> 73 >>> Mark >>> N5KAE >>> >>> >>> >>> >>> ----- Original Message ---- >>>> From: Michael A. Kelly<[email protected]> >>>> To:[email protected] >>>> Sent: Tue, November 1, 2011 8:49:00 PM >>>> Subject: [Drakelist] Side Tone Adjustment for TR4CW Possible? >>>> >>>> Howdy, >>>> >>>> I had a 12AV6 tube (V2) go soft and after replacing it the "chirpy" >>>> audio for the side tone went away, (no chirp on the transmitted >>>> signal, just on my end) but the new side tone pitch is higher than I >>>> prefer. Is there an way to adjust the side tone audio to get it down >>>> in the 700-750 Hz range? (not volume, but pitch) >>>> >>>> Thanks, >>>> >>>> Michael N4MAK >>>> >>>> _______________________________________________ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
