I have tried this using a Grado, a Sony, and a David Clark headset and have not experienced it with any of them.
On Wed, Feb 16, 2011 at 5:02 PM, Larry Goga <[email protected]> wrote: > Gentlemen: > > From the day I received my Flex 5K, now over a year ago, I noticed what I > believed to be an excessive DC level on the front panel headphone connector. > Scott's message below made me go do some testing and here is what I found. > > It's easy to experience this DC level. All you have to do is have the > checkbox in the Mixer panel under Headphones selected (a check in the box) > and if you plug in the headphones or twist the connector in the Phones jack > on the front of the Flex and you'll hear a severe transient or a lot of > static in the headphones. The static comes from the fact that there is DC > on that connection. I have worked in professional audio for 40 years and I > know that DC on an audio connection of any kind is something to be avoided > at all costs. > > Measuring across the stereo outputs of the Phones jack with a Fluke 8060A > DMM shows that there is in excess of 2.4 VDC on both channels of that > connector. Looking across the stereo outputs of the Phones jack with a > scope confirms the presence of the same DC level and shows a variable rise > time and fall time. I have seen rising and falling time constants as slow > as 5 or 6 seconds and as fast as 250 milliseconds. I have not yet been > able to figure out what causes the change in the TC, but it is there. You > can see the change in level by checking and unchecking the box in the Mixer > panel. > > The Volume slider on the Mixer panel has no effect on this DC level. The > Mute All Outputs on the Mixer panel has no effect on this DC level. The > Mute button on the PowerSDR front panel has no effect on this DC level. The > only thing that makes this DC level come and go is the check box on the > Mixer panel under the Headphone control. > > I have tried two different headphone, both Sony's, one MDR-V150 and one > MDR-7506. The former has an impedance of 24 ohms per driver while the later > has an impedance of 63 ohms per driver. Both sets perform admirably on my > Kenwood TS-450SAT and my Yaesu FT-875D. The only place I experience these > DC transient issues is on the Flex 5K. Loading the output of the 5K with > either of these headphones will cause the DC voltage level to decrease, but > it is still well above 2 volts DC peak. > > Finally, if I switch the Fluke DMM to read current, I can pull over 100 ma > of DC current out of the Phones jack on each channel. > > My only solution to these problems is to make sure that I am NOT wearing > any headphones when I either plug them in or turn them on. > > I suggest that there might be something with the design or operation of the > headphone driver circuit that would cause these problems and I believe that > Scott's problems might be related to these issues. > > To answer Neal's question, I have no problem with the audio signals from > the Power Speaker Output connector on the rear of the 5K. However, when the > PTT switch is released there does appear to be another DC transient. I can > hear it in the speaker and headphone outputs and see it in the panafall > display. I'm not sure what that's all about, but the switching just doesn't > seem to be clean. I don't recall it being there before I sent my 5K back > for the VU upgrade, but maybe it was there and I just missed it. > > Respectfully submitted, > > Larry Goga, AE5CZ > > > > On Feb 16, 2011, at 10:34 AM, Neal Campbell wrote: > > Are you getting good sound out of the powered speakers? >> >> 73 >> Neal Campbell >> Abroham Neal Software >> www.abrohamnealsoftware.com >> (540) 645 5394 NEW PHONE NUMBER >> >> Amateur Radio: K3NC >> Blog: http://www.abrohamnealsoftware.com/blog/ >> DXBase bug reports: email to [email protected] >> Abroham Neal forums: http:/www.abrohamnealsoftware.com/community/ >> >> >> >> >> >> On Wed, Feb 16, 2011 at 9:35 AM, Tim Ellison <[email protected]> wrote: >> >> Are you using stereo headphones? >>> http://kc.flexradio.com/KnowledgebaseArticle50145.aspx >>> >>> >>> -Tim >>> >>> >>> -----Original Message----- >>> From: [email protected] [mailto: >>> [email protected]] On Behalf Of Scott Simmons - WA4DOS >>> Sent: Wednesday, February 16, 2011 9:08 AM >>> To: [email protected] >>> Subject: [Flexradio] only Clicking out of headphone jack >>> >>> Just received my new 5000a and smiling ear to ear..no glitches setting up >>> and getting it running (PSDR V 2.016, Win 7 64 home premium). >>> >>> BUT no sound out of the headphone jack except rhythmic, LOUD clicking. >>> Mixer was checked for headphones and powered speakers. I've tried two >>> sets >>> of headphones. Volume makes no difference on intensity of the clicking. >>> >>> Any thoughts or suggestions?? >>> >>> >>> >>> AMD Phenom II X4 955, 8 GB RAM. >>> >>> Scott S WA4DOS >>> >>> >>> >>> _______________________________________________ >>> FlexRadio Systems Mailing List >>> [email protected] >>> http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz >>> Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ >>> Knowledge Base: http://kc.flexradio.com/ Homepage: >>> http://www.flexradio.com/ >>> >>> _______________________________________________ >>> FlexRadio Systems Mailing List >>> [email protected] >>> http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz >>> Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ >>> Knowledge Base: http://kc.flexradio.com/ Homepage: >>> http://www.flexradio.com/ >>> >>> _______________________________________________ >> FlexRadio Systems Mailing List >> [email protected] >> http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz >> Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ >> Knowledge Base: http://kc.flexradio.com/ Homepage: >> http://www.flexradio.com/ >> >> > > _______________________________________________ > FlexRadio Systems Mailing List > [email protected] > http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz > Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ > Knowledge Base: http://kc.flexradio.com/ Homepage: > http://www.flexradio.com/ > _______________________________________________ FlexRadio Systems Mailing List [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flexradio.com/ Homepage: http://www.flexradio.com/
