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Carl,
First of all, many thanks for creating this project! It looks like it should be really interesting to experiment with.
After reading your latest manual for the PI-1, I've decided to build the Option 1 version with the addition of the Q3 active cutoff. I'd also implement the output filtering of the NE5534 if I understood its purpose. If some commercial PI detectors use it, one would think this filtering would serve some purpose. However, when you state that some manufacturers use the low-pass and others use the high-pass filter option, that confuses me as to the advantage or purpose of either.
Most importantly, I want to build a PI detector that can serve well in practical use while retaining the experimental options you have designed into it. As such, I'd like to build a detector with the most useful adjustments appearing as external controls, a number of trimpots accessible with the case closed (mounted on a perfboard aligned with holes drilled into the case) for the most useful experimental adjustments and, if applicable, the adjustments needed only for calibration limited to less accessible trimpots on the PCB. Since I've only owned IB detectors up until now, can you give me an idea of which potentiometers fit into each category mentioned.
On another subject, would there be any advantage in using the very slightly more expensive NE5534A (rated lower noise) version of the NE5534 in your design?
Thanks,
Bill Blair
First of all, many thanks for creating this project! It looks like it should be really interesting to experiment with.
After reading your latest manual for the PI-1, I've decided to build the Option 1 version with the addition of the Q3 active cutoff. I'd also implement the output filtering of the NE5534 if I understood its purpose. If some commercial PI detectors use it, one would think this filtering would serve some purpose. However, when you state that some manufacturers use the low-pass and others use the high-pass filter option, that confuses me as to the advantage or purpose of either.
Most importantly, I want to build a PI detector that can serve well in practical use while retaining the experimental options you have designed into it. As such, I'd like to build a detector with the most useful adjustments appearing as external controls, a number of trimpots accessible with the case closed (mounted on a perfboard aligned with holes drilled into the case) for the most useful experimental adjustments and, if applicable, the adjustments needed only for calibration limited to less accessible trimpots on the PCB. Since I've only owned IB detectors up until now, can you give me an idea of which potentiometers fit into each category mentioned.
On another subject, would there be any advantage in using the very slightly more expensive NE5534A (rated lower noise) version of the NE5534 in your design?
Thanks,
Bill Blair
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