[TenTec] Ear Phone Audio

[Gary Follett]

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.
>>>