[TenTec] Ear Phone Audio

[Arthur Lewis]

*Thanks Gary..*

*Art WA8VSJ*

On Wed, Aug 24, 2016 at 3:39 PM, Gary Follett <dukeshifi at comcast.net> wrote:

> No, it does not. The issue you now describe will require that I look at
> the schematic tonight and get back to you.
>
> Sent from my iPad
>
> > On Aug 24, 2016, at 1:58 PM, Arthur Lewis <wa8vsj at gmail.com> wrote:
> >
> > *Gary,*
> > *Thanks for your comments on my earphone problem. The part that is a bit
> > confusing is the fact that when I turn up the volume with the earphones
> in
> > use, the sidetone on CW is head banging loud in the phones. Does the
> > sidetone use a different audio source?  *
> >
> > *Art WA8VSJ*
> >
> >> On Wed, Aug 24, 2016 at 2:32 PM, Gary Follett <dukeshifi at comcast.net>
> wrote:
> >>
> >> Yes, and the peak to peak available output from an Orion, about 13 volts
> >> p-p, should produce head banging volume in virtually any headphone if
> >> working properly, even the old "cans" from the 1930's.
> >>
> >> You need to be looking at things that can affect both channels of the
> >> output since, at this point in the circuit, the thing is operating in
> >> stereo. This precludes defective dropping (ear protection) resistors or
> >> wiring problems. It is looking like the headphone amp output is
> defective.
> >>
> >> Gary
> >>
> >> Sent from my iPad
> >>
> >>>> On Aug 24, 2016, at 12:32 PM, Jim Brown <k9yc at audiosystemsgroup.com>
> >>> wrote:
> >>>
> >>>> On Wed,8/24/2016 10:08 AM, Robert P. Santella wrote:
> >>>> Impedance needs to be 30 ohms.
> >>>
> >>> NO! Headphone impedance is NOT critical. Audio power amplifiers are
> VERY
> >> different from RF power amplifiers. Virtually all audio amplifiers are
> low
> >> impedance sources, and are designed to drive any impedance greater than
> a
> >> design minimum. For example, the source impedance of a loudspeaker
> output
> >> stage is a small fraction of an ohm, and is designed to drive any
> >> loudspeaker load greater than 4 ohms. The relationship between these two
> >> impedances is called the "damping factor," and 100 is a typical value. A
> >> well-designed headphone amp will include a low-value resistor in series
> to
> >> protect the amplifier from being shorted when headphones are being
> plugged
> >> and unplugged.
> >>>
>
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