@Handy Andy had a graph of this some years ago (may have been the
other forum. )
Picture worth a thousand words as it were.
Your problem with the 2K sounds like incorrect mic jack wiring rather than carrier insertion points.
Again , simple test. Turn the audio up on a dead frequency (or antenna disconnected) and switch between USB and LSB . If the static changes pitch between the two something is not right.
You mean this one?
You may also have another condition...
High-frequency rolloff issues -
@Robalo - had found a Hi-Frequency Cut filter some time ago...
But, that's for ALL audio - you seem to have more of a CENTERING issue around the IF versus BFO detect being sent to convert directly into Audio.
If you use a 148/Grant XL or even a 142 type chassis - L13 and L14 versus the 7.8MHz BASE detected off of L14 COMPARED TO X1 - X1? It's your 7.3450MHz onboard fixed reference to decode what exists off the differences between it and the 7.8MHz (455kHz) (AM) Somewhere between the L13 and L14 -(In SSB) your 7.8 BASE reference and your IF reference (from X4) - it may be why you seem to have high - frequency "Shrill" sounding audio.
Since you can't re-tune X1 unless you replace it - not recommended - you Retune L50, L22 and L23 to re-center the PLL's references - this skips the Audio side to make your radio tune BFO directly into the midrange - but in doing so, you have to retune CT2 L30 and L31 side also - just to bring the Shrill sound of the SSB modes - into the more Alto or Midrange you'd expect to hear.
You can always place a 0.01uF (103) Disc cap one on the hot side, and ACROSS to Shield can ground somewhere along the way (these radios have a Hi/Lo Tone switch for this) the Audio Out line to the Volume control and if they "Tuned" using the Lo side of the TONE switch - they overdid the tune.
In a PC 122 you can do a similar trick to "average out" the Hiss in-between modes. But that requires you to know how and what references to use...
- Lower Side Band - referring to LOWER side of the Channel center frequency - you SLOW DOWN PLL Side and SPEED UP the Audio side (The one that goes to the AN612 or Deconversion IF)
- This shifts Audio Passband to BASS region
So that means the IF Frequency Counter may show LOWER than expected - which to me is why I'd just rather run the CLARIFIER and do all the AUDIO adjustments and leave the Frequency counter off - just focus on the QSO
- Upper Side Band = referring to HIGHER than the center of the Channel Frequency - YOU SPEED UP PLL side and SLOW DOWN the Audio side of the IF to obtain those lower BASS tones. The AN612 and Deconversion IF sections respond accordingly.
- This is shifting the Passband - again, to LOWER BASS tones.
Why does this work this way?
Because of the issue of the Beat Frequency Oscillations - your BFO., Clarifier, Voice Lock - That Galaxy KNOB that says COARSE and FINE.
Look up Heterodyne and understand the concepts of mixing two frequencies to make a third - derived from the difference between the other two.
Then the SSB centering will come easier and you're less likely to say - you're 1kHz off the rest of us.
You just tune to it and once set - forget it and just chat...Just like Dobie Gray, and Drift away...