Scott - Just now saw your post. Thank you for joining us!My article in Linear Audio Vol. 10 is out. I cover IIR and min phase FIR using a trick that I have not seen elsewhere. The IIR coefficients are tablated there for <.005dB accurate response even at 48K sampling for RIAA and most of the historical equalizations. I only posted the FIR's for RIAA but supply the Python code to do any you might want. The min phase FIR at 96K is only ~5k taps but does .000002 dB and .000001 Degrees even down to 20Hz.
I guess I'll have to get a real job too and subscribe to Linear Audio.
I'm pretty happy with how DC8's RIAA sounded compared to CoolEdit's RIAA but I have a DC8 learning curve.
I had strange things happen with it truncating files but that might be because I was using 32 bit float as my test source.
Now that I have the preamp in a box I decided it was time to upgrade phono cartridges.
I did this on the cheap having two Stanton 681EE bodies and a 2/3 full three-pack of D6800EL styli given to me by a radio station many years ago.
I've basically been using the AT-96 for testing since it was also free.
The AT-120 from my youth needs a new stylus...
One thing I noticed about the AT-96 is that it has no grounding strap from either the left or right ground connection to the body.
All of my other carts do.
The ADC LME-2 head shell is plastic and galvanically isolated from any tonearm lead.
The AT-96 also has a plastic outer shell and plastic mounting ears.
The AT-96 tended to have - depending on arm position - electrostatic induced noise the left channel didn't have.
When the arm was hovering over the turntable all was well but on the tonearm rest it was about 3 dB noisier when the room's dimmer was on located about 3 feet from the cartridge.
Approaching the cartridge body or mounting screws the left channel remained silent but the right channel would have this slight noise increase.
I got the feeling that the AT-96 had it's internal shield or frame bonded to the right channel ground.
Playing a record both channels were quiet.
When I mounted the Stanton I purposely left the ground strap on.
Sure enough this cartridge had the same noise signature but in the opposite channel.
Touching the metal body produced bodacious amounts of hum in that channel which is what we should expect in a balanced and floating connection.
It unbalances the circuit.
The bonding clip to the cartridge metal outer body can be slid off the ground post to provide a true floating connection.
(The grounding clip can also be re-installed - the clip slips between the outer metal shell and the cart's plastic terminal block.)
When I removed the bonding strap both channels were equally quiet regardless of arm position.
For a true balanced connection the clip should be removed and the metal cartridge body allowed to float.
That way I get the best CMR in both channels.
The Stanton 681 sounds absolutely fantastic.
The AT-96 was OK but now that I'm done experimenting with the preamp it was worth the no-cost upgrade.
Noise Signature of Balanced Input Phono Preamp Input Termination Stanton 681 on Turntable with RIAA EQ
0 dBFS is +8 dBu, Gain at 1 kHz approx 34 dB
Noise Signature of Balanced Input Phono Preamp Input Termination Stanton 681 on Turntable Flat, No RIAA