Woody do you have the version 4 board with the discreet audio amp? If so checkout the archives or Wiki page for a fix/mod for the amplifier. There were some builders that had distorted audio output and to me your recordings sound like that audio distortion. If you can inject a carrier input compare your audio signals at the high side of the volume control and then your output. You can also look at the collector of Q71 which should be the same as the volume control only a larger level.?
If you have the IC amplifier then the chip maybe bad.?
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On Oct 24, 2018, at 16:51, Woody <
mailme@...> wrote:
Will give that a try, but suspect it is
not the source of the problem.? The speaker out feeds the top of a
500 ohm potentiometer.? Adjusting the drive level to the off board
amp with the pot? (wiper) affects volume available, but doesn't
affect the audio quality.
Attached, FWIW, are two mp3 clips.? "compare 2 noise" is with the
antenna attached, but no signal. First is the ubitx, followed by
the K2. Note: I do have a bit of power line noise.?
"compare 2" is of a 40M QSO.? Ubitx first, then the K2.
--------------
Tried the off board amp, tapping into earlier audio stages.? Input
level so low, could not hear the output
-----------------
Still scratching my head!?? Compared the ubitx to my Elecraft K2
by switching the antenna to each on a S5 (on K2) signal.? The RF
sensitivity is not as good as the K2 and (still) shows some
distortion.
WELL, WELL, WELL...
Pulled out the o'scope and made some measurements.? I think I have
a bad ubitx.? I can only get a measurable signal from CLK 0 - TP18
reads 1.3 v PP.?? TP15 (CLK 1) and TP12 (CLK 2) are below what I
can measure with a 5mv scale with 10x probe.? It is a wonder I
hear anything!!!? Also may explain the super low audio when I do
hear something.? Probably why the BFO adjustment is really weird
too.
Here is a list of the TPs I have checked (no antenna):
TP 1? -? Zero (zero = below readability)
TP 12 -? Zero? (CLK 2) No signal either side of R100 either.
TP 14 -? Zero
TP 15 - Zero? No signal either side of of R106 either.
TP 18 - (CLK 0)? 1.3 v PP
Note that "Zero" may have some signal, but below my scope's
measurement capability.
Measured the Raduino directly where it plugs into the main board.
Confirms what I saw above.? Pin 19 (CLK 0), lots of signal.? Pin
16 (CLK 1), no signal.? Pin 13 (CLK 2) no signal.
Looks like I need to contact HFsignals.
Woody, KZ4AK
On 10/24/2018 16:27, Richie Chambless wrote:
Woody?
I just listened to your sound clips and I heard distortion that¡¯s
usually produced when a source signal overdrives the next stage.
Where are you connecting your outboard amp? I would think that you
would get distortion if you connected it to the speaker out (8 ohm
impedance). I would tap the audio at the volume pot (top lug) if
you haven¡¯t already.?
<compare 2 noise.mp3>
<compare 2.mp3>
Skip Davis