FWIW, standard Line Out is 1Vp-p at 600 ohms line impedance. matt
On Wed, 17 Dec 2008 01:01:51 -0500, you wrote: > > >> Consumer line level ins and outs are designed to handle levels >> corresonding to a sine wave of at least 1V. 1.4v peak, 2.8v >> p-p. 600mV p-p is 13 dB below that. So yes, I agree with the >> guy who says that the Line Out level is pretty low. Sorta like >> a hot mic level. :) > >Unfortunately, amateur manufacturers have never used the consumer >definition of "line level." Every manufacturer seems to have a >different definition for both level and impedance ... from 100 mV >at 50K to 4V p-p at 600 Ohms. > >With the AF output mod (47 Ohms in series with the primary of the >Line Out transformers), the K3's Line Out looks reasonably clean >at 1V or more of audio. Prior to the change, harmonic distortion >got fairly bad above 600 mV p-p. > >The absolute audio level is highly dependent on AGC settings - or >the gain reduction caused by AGC action. > >73, > > ... Joe, W4TV > > > > > >> -----Original Message----- >> From: [email protected] >> [mailto:[email protected]] On Behalf Of Jim Brown >> Sent: Tuesday, December 16, 2008 7:25 PM >> To: [email protected] >> Subject: Re: [Elecraft] LINE OUT output too low? >> >> >> On Tue, 16 Dec 2008 13:16:28 -0800, Lyle Johnson wrote: >> >> >On my K3, with the AFMODKT changes in place on the KIO3 board, and >> >driving an open circuit, I get up to 600 mV p-p of audio >> output if LINE >> >OUT is set to 100 while listening to a moderately strong signal with >> AGC >> >activated. This of course depends on the signal strength, >> AGC settings >> >and so forth. >> >> >A typical output level is less, since the LINE OUT is >> normally set much >> >lower than 100. >> >> Consumer line level ins and outs are designed to handle levels >> corresonding to a sine wave of at least 1V. 1.4v peak, 2.8v >> p-p. 600mV >> p-p is 13 dB below that. So yes, I agree with the guy who >> says that the >> Line Out level is pretty low. Sorta like a hot mic level. :) >> >> Now, audio is dynamic, and except for CW, is almost never a >> sine wave. >> Rather, it's dynamic, with its level varying widely depending on >> program. The RMS value of unprocessed (no compression or limiting) >> speech and music is typically 14 dB below the peak level. But >> think of >> it this way -- the audio circuitry has to be able to handle ALL the >> voltage in the audio stream, including all the noise and QRM, >> and most >> of that noise is very "spiky" -- that is, their peaks are >> often 20-30 dB >> hotter than their average value, and those peaks can clip and create >> distortion long before the signal distorts, making the audio a real >> mess. Bottom line -- an audio output stage for a >> communications RX needs >> a lot of headroom. >> >> 73, >> >> Jim K9YC >> >> >> _______________________________________________ >> Elecraft mailing list >> Post to: [email protected] >> You must be a subscriber to post to the list. >> Subscriber Info (Addr. Change, sub, unsub etc.): >> http://mailman.qth.net/mailman/listinfo/elecraft >> >> Help: http://mailman.qth.net/subscribers.htm >> Elecraft web page: http://www.elecraft.com > >_______________________________________________ >Elecraft mailing list >Post to: [email protected] >You must be a subscriber to post to the list. >Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > >Help: http://mailman.qth.net/subscribers.htm >Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
