CZ Threshold

Tom, when the threshold is set on a CZ (5 or 20) and the disc is changed from auto-tune to say, perhaps 0 or 1, what, if any effect does this have on the machine, or is the auto-tune circuit threshold independent of any other disc settings, and does the threshold have any effect other than in the auto-tune mode? Does that make sense?

If you are running in autotune and hear the 'threshold', the sensitivity is gotta be in the 9-10 range (at least from all the CZ's I have used that's when I start to hear it). That's way too high for discriminate mode in the sense that the unit would be subject to a lot more falsing and no increase in depth. So when you have the unit in autotune with that high of a sensitivity level and switch over, you have to lower the sensitivity to the 4-5 range to have a much more stable unit. I believe running in the 9-10 range in sensitivity in discriminate mode, the coil is hotter and has a 'wider' range but not deeper.

Since the CZ is a silent search unit, that 'threshold' is really not a true to sense threshold that you would find in threshold based units ( at least I think I read that somewhere).

The expert, Tom D, will chime in I am sure and give the most accurate response.

Thanks, Rover, Ithink you are correct but would like to know if the unit does not have a proper threshold in auto-tune, will that affect the disc circuirts?

I guess I am confused when you state proper threshold. Are you saying you can't hear that 'threshold warble' type sound in autotune mode with the sensitivity all the way up ?

Remember, if the sensitivity is set to let's say 8 in autotune mode and you can't hear that threshold type sound, when you switch to discriminate mode, your sensitivity will still be too high to run stable with the propensity to have increased falsing and a much hotter coil, without any real increase in depth.

In discriminate mode, it's silent search and I believe independent of any 'threshold' setting. I think the real function of that threshold type sound is to help in ground balancing so you can hear the difference in the sound when pumping the coil. It can be set in autotune mode via the sensitivity setting to just barely warble and you would hear a target break through and make that sound pitch higher. At a lower sensitivity setting where the sound just goes away, a target will still sound off and break through and make that higher pitch sound.

Hey Tom....where you at ? HA !

There is a dramatic difference in "Sensitivity" application...... when comparing Disc vs Autotune. For instance............ If you are in any of the Disc settings (Disc 0 - 6)...and you have a Sens setting of '5'...... you will have maximum depth/minimum width. If you were to switch over to all-metal "Autotune"...... still keeping Sens on '5'........ you will have substantially reduced power/sensitivity/depth...... along with no threshold 'hum'. If you want to restore the unit back to full depth capabilities whilst in Autotune...... you will need to increase Sens up to a comfortable threshold hum...... which is usually a Sens setting of 9 - 10. On a CZ platform...... when you are in the Autotune mode...... this is direct/raw data...... minimum filtering.

When you switch over to Disc mode (any of the other settings that are NOT 'Autotune')......... then there is zero correlation (and zero carry-over) between Autotune and Disc. ,,, In other words; where ever the threshold is set at...whilst in Autotune.......... makes no difference in performance....when you switch over to Disc mode.

If you are talking about the Gold Bug-2....... then there IS a difference. On the GB2 ..... when you are in Iron Disc mode..... the threshold control (on the back of the control box......just above the battery doors)..... does indeed affect the Disc performance.......,,,,,...... which is incongruent with owner/operator manual. You can easily verify this by testing a tiny nugget whilst in Iron Disc mode.......... and comparing the performance difference by rotating the 'threshold' control from one end ...to the other end. Not so...with a CZ.

Thanks, Tom, just what I wanted to .

Thank you Tom for that explanation.