[Elecraft] K3S SSB TX monitor - feature request

[Joe Subich, W4TV]

On 4/8/2017 2:19 PM, Dave Fugleberg wrote:
> 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.

That is *NOT* my experience.  With 5.57, the front and rear panel
headphone jacks behave identically here.  You may be confusing the
Phones and Line Out jacks.

73,

    ... Joe, W4TV


On 4/8/2017 2:19 PM, Dave Fugleberg wrote:
> 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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