Re: [AMRadio] Ranger Audio... the Pics
Hello Jack: One last suggestion from me, if you use a headphone near the microphone it can form a Helmholtz resonator effect which is to say that the audio will be narrowed up so I would use a speaker (3-10 inch dia) as a source. Is there no one near you who can help?? Good Luck. Charlie, K0NG __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Ranger Audio... the Pics
I did some more sig tracing and came up with some pics of where the trouble seems to be. Putting a 500 hz sine wave into the mic input, I see a nice sine wave until I get to the modulator tubes. The grid in standby looks close enough but when I go to phone mode it gets flaky. The plates look really flaky in standby but look more normal in phone mode but there seems to be a bunch of waves competing for the space. I posted some pics to http://schmidling.com/mod.jpg Comments eagerly awaited js -- PHOTO OF THE WEEK: http://schmidling.com/pow.htm Astronomy, Beer, Cheese, Fiber,Gems, Sausage,Silver http://schmidling.com __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Ranger Audio... the Pics
[EMAIL PROTECTED] wrote: Just my opinion. I have not been following the problem. What are you looking for?? Well, the current problem is the fact everyone complains about my audio. Tinny, yucky, narrow... like an old telephone, etc. New (used) D104 is the worst of the bunch but known good mics that I have used for years, doing voice overs for film and video don't sound much better. I taped tests of 3 of them and the D104 sounds lousy and the dynamic and electret lapel sound just fine and are nearly indistinguishable from each other. When I put them under an earphone tuned to a good broadcast signal and fire the Ranger into a dummy or antenna, they all sound lousy. Seems obvious the Ranger is doing something to the audio so I have been sig tracing to see where and the pics are what I found. In the meantime, I removed caps one at a time from the front end and none of them made the slightest difference. I left them all out and decided it's time for a break. I have no idea where to go from here. js -- PHOTO OF THE WEEK: http://schmidling.com/pow.htm Astronomy, Beer, Cheese, Fiber,Gems, Sausage,Silver http://schmidling.com __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Ranger Audio... the Pics
[EMAIL PROTECTED] wrote: Hi Jack: You did not give any reference to the p/p amplitude of the signals?? Missed this but I posted the numbers in a previous post but basically, they started at about 10 mv and increased with each step but I was in error with the 6l6 plate saying it was 50 v when in fact it was about 200v. I had forgotten to calibrate the scope before running the tests. The relationships were right but the absolute numbers were all too low. I actually measured them all again for the pics but when I got to the end I realized the problem and didn't fell like running them again so I didn't include the new numbers but all the stages amplify which I guess is what counts. js -- PHOTO OF THE WEEK: http://schmidling.com/pow.htm Astronomy, Beer, Cheese, Fiber,Gems, Sausage,Silver http://schmidling.com __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Ranger Audio... the Pics
I have no idea where to go from here. My advise is to crack open a beer and relax. The Radio will be there tomorrow klc - Original Message - From: Jack Schmidling [EMAIL PROTECTED] [EMAIL PROTECTED] wrote: Just my opinion. I have not been following the problem. What are you looking for?? Well, the current problem is the fact everyone complains about my __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Ranger Audio... the Pics
To repeat an earlier comment, try a load resistor on the output leads, say 5K or something in that range at least 20 watts and 50 watts would be ideal for full power tests. Pull the 6146 and the osc tubes to get rid of the RF. You have to have a load on the mod iron to keep things under control. The waveform that is puzzling is the 6L6 in standby. What is the amplitude? Looks like we have a parasitic oscillation in the amp circuit and it could still be there mixed in with the audio on xmit. There is hum too as it is showing up as a variation in the peak amplitude of the 500 Hz wave. You'll have to put back the bypass caps to gain some control over the RF getting into the audio. Maybe a few RF chokes in the audio lines to eliminate the RF. As you have seen. sticking the scope probe into a medium or low impedance is OK usually. But a high impedance like the 6L6 grid introduces more errors. Another antenna. Larry Jack Schmidling wrote: I did some more sig tracing and came up with some pics of where the trouble seems to be. Putting a 500 hz sine wave into the mic input, I see a nice sine wave until I get to the modulator tubes. The grid in standby looks close enough but when I go to phone mode it gets flaky. The plates look really flaky in standby but look more normal in phone mode but there seems to be a bunch of waves competing for the space. I posted some pics to http://schmidling.com/mod.jpg Comments eagerly awaited js __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
