No, I did not design the AD797. That was Scott Wurcer- a colleague at ADI and, incidentally, for whatever it's worth, also an ADI design fellow. However, I know the design quite well.
He and I were colleagues in the opamp group in the 80s. He focused on high performance relatively low frequency opamps such as the AD712 and then the AD797, amongst others.
I focused on high performance high speed amps like the AD843, 845 (at one point an audio darling), 846 (also a transimpedance design with some very interesting design aspects that I gave an ISSCC paper on) etc. etc. mostly using a complementary bipolar process that I helped develop that I believe was also used in the AD797. I also did things like designing the FET based AD736/737 RMS-DC converter and others.
I moved on to more RF, disk drive read/write, GSM, CDMA etc. transceivers, signal processing, PLL and DSP designs.
Anyway, what the heck does "cartridge energy" actually mean?
It's an electromagnetic transducer that I grant you has a fair degree of non linearity (which is one of the reasons I like the Madake- it's quite low distortion for a cartridge and why I have ML Monti loudspeakers as most loudspeakers have far too much distortion for my taste) so it generates a voltage and has an output impedance.
I can vouch that the Miyajima cartridges respond to ticks and pops just about as you would expect based on their frequency response and the amplitude of the signal generated, so no alternative explanations are necessary. Are you perhaps stating that the increased current generated by the lower resistive load increases distortion? If so, I can say that I believe that it's not true for the Madake as I've measured IM and harmonic distortion under varying load conditions (Ah the joys of test records)- and they are really sensitive to cartridge alignment but not that I can tell, to load.
And yes, I'm well aware of the SUT impedance transformations- and I also model them, although imperfectly, in LTspice, which uses calls to set up the parameters. This can be quite insightful, for example are you aware of the LF response sensitivity to winding inductance?
One of the "joys" of being an IC designer is the compulsion to measure/model everything! However, once the skills are developed it's relatively easy to do as long as someone else has done the hard work of producing suitable models to use.
Constructing an electrical model for the Madake was fraught with concern as using my own meters to measure the capacitance and inductance was anxiety producing.
Then when I plugged the parameters into the simulation and compared against my measured output I realized that the actual response had precious little to do with the electrical characteristics and everything to do with the mechanical resonances.
And so, the journey began...
He and I were colleagues in the opamp group in the 80s. He focused on high performance relatively low frequency opamps such as the AD712 and then the AD797, amongst others.
I focused on high performance high speed amps like the AD843, 845 (at one point an audio darling), 846 (also a transimpedance design with some very interesting design aspects that I gave an ISSCC paper on) etc. etc. mostly using a complementary bipolar process that I helped develop that I believe was also used in the AD797. I also did things like designing the FET based AD736/737 RMS-DC converter and others.
I moved on to more RF, disk drive read/write, GSM, CDMA etc. transceivers, signal processing, PLL and DSP designs.
Anyway, what the heck does "cartridge energy" actually mean?
It's an electromagnetic transducer that I grant you has a fair degree of non linearity (which is one of the reasons I like the Madake- it's quite low distortion for a cartridge and why I have ML Monti loudspeakers as most loudspeakers have far too much distortion for my taste) so it generates a voltage and has an output impedance.
I can vouch that the Miyajima cartridges respond to ticks and pops just about as you would expect based on their frequency response and the amplitude of the signal generated, so no alternative explanations are necessary. Are you perhaps stating that the increased current generated by the lower resistive load increases distortion? If so, I can say that I believe that it's not true for the Madake as I've measured IM and harmonic distortion under varying load conditions (Ah the joys of test records)- and they are really sensitive to cartridge alignment but not that I can tell, to load.
And yes, I'm well aware of the SUT impedance transformations- and I also model them, although imperfectly, in LTspice, which uses calls to set up the parameters. This can be quite insightful, for example are you aware of the LF response sensitivity to winding inductance?
One of the "joys" of being an IC designer is the compulsion to measure/model everything! However, once the skills are developed it's relatively easy to do as long as someone else has done the hard work of producing suitable models to use.
Constructing an electrical model for the Madake was fraught with concern as using my own meters to measure the capacitance and inductance was anxiety producing.
Then when I plugged the parameters into the simulation and compared against my measured output I realized that the actual response had precious little to do with the electrical characteristics and everything to do with the mechanical resonances.
And so, the journey began...
