[Elecraft] K3S SSB TX monitor - feature request

[Dave Fugleberg]

I think some of the misunderstandings on this thread are because the front
and rear panel Phones jacks behave differently. Here's the deal:
1) the original poster is using the front panel PHONES jack, and has
SPKR+Phones set to NO. This makes the radio behave like most rigs we're
used to - i.e., plugging in the phones mutes the speaker. In this case, if
Monitor is on, it comes through phones OR speaker, whichever you're using
at the time.  There is no provision to enable/disable Monitor based on
whether the front panel phones are plugged in, which is what he wants.

2) If you use the REAR panel phones jack, the monitor audio comes through
the phones as expected. If SPKR+PHONES is set to yes, the RX audio comes
through the speakers, but the transmit Monitor audio does not.


At least, that's the behavior with my K3, MCU version 5.57.  I just tested
the two scenarios above.  For the record, my normal configuration is to use
the rear panel phones and mic jacks, with SPKR+PHONES on.  I do have PF1
set to toggle that off, but rarely do, since I'm usually alone in the
shack.  I have yet to hear any kind of audio feedback when transmitting.  I
have no idea if the behavior is any different using the front MIC jack, as
I never do.

I'd be interested to hear if anyone has a different experience.

Incidentally, while testing option 1 above, I unplugged the phones from the
front and cranked the MONITOR until it was unpleasantly loud from the
speakers, but got no feedback howl, but that may just be a function of
placement.

On Sat, Apr 8, 2017 at 1:02 PM, Richard Lamont <richard at lamont.me.uk> wrote:

> On 08/04/17 18:11, Joe Subich, W4TV wrote:
> >
> >> On 4/8/2017 2:24 AM, Richard Lamont wrote:
> >>> The firmware, however, does not appear to support what seems a simple
> >>> and common-sense requirement.
> >
> > It is *not* the firmware - it is the *hardware* that does not support
> > what you call a "simple and common-sense requirement" and what others
> > call stupidity.  Perhaps you should study the schematic - at least of
> > the K3 which is published.   Notice on the sheets K3 DSP: CODECS and K3
> > DSP:DAC AUDIO the headphone/speaker amplifiers are fed *IN PARALLEL*.
> > LHPOUT/RHPOUT of U7 (the DC) goes through the audio lowpass filter to
> > U1 (speaker amplifier) and U2 (headphone amplifier) *IN PARALLEL*.
> > *THERE IS NO POSSIBLE WAY* to send monitor audio *to only* the
> > *headphone amplifier* (or for that matter *only* to the speaker).
>
> I studied the K3 schematics a few days ago. I've just studied them
> again. Thanks for the reminder.
>
> On receive, the rig is capable of muting the speakers when the
> headphones are plugged in. This is quite normal. This happens despite
> the two audio amplifiers having parallel inputs.
>
> There are switch contacts on the front panel headphone jack that enable
> the rig to 'know', firmware permitting, whether there's a jack plug in
> the socket. There is also a line labelled MUTE1 connected to the pin 2
> of the speaker amplifier U1.
>
> So the hardware exists to enable the firmware (a) to know whether
> headphones are plugged in, and (b) to mute the speaker amplifier. This
> hardware is, AFAICS, used on receive. All I'm asking for as an option to
> do the same thing on transmit, if a particular set of circumstances is
> true:
>
> Is the rig on a voice mode?
> Is the audio input set to mic (not line in)?
> Is the rig transmitting?
> Is there nothing plugged into the front panel headphone socket?
>
> If these four conditions are all true, then mute the speaker amplifier.
>
>
> 73,
> Richard G4DYA
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