New Gold Note PH 10

A couple of comments:

First, Clakster's  AT-20Sla if I recall was a Shibata diamond on an Aluminum cantilever; this was very similar to the AT15s Universal.  I had one of those last summer which I tested against the AT15ss/20ss which is a super Shibata on a Beryllium cantilever and there is quite a difference in upper end performance.  The aluminum item sounds much more mellow, almost muffled in comparison.  Therefore I would understand why a 100K ohm input would be helpful as it opens up the high frequencies more.  Since I am using the AT 20ss which has a huge frequency excursion of 5-50K hz, it's much more detailed on the upper frequencies and when I run it on 47K ohm input, it's superb.  If I were to get any additional boost in upper range by going to 100K ohms, I think it would not be a good match at all.  The Audio Technica factory suggested loading for the 20ss is 47k with 100-150 pf.  They are probably assuming some average for capacitance in the audio leads from the cartridge to the amplifier at some average user length which may be 3 to 6 feet.  I am using around 2.5 feet, so my capacitance is lower, hence the 220 pf I have works.

The other comment from Lew pertaining to grounding, I am not using generators.  I have an Amateur Radio station with very extensive antennae and high power amplifiers.  Since one HF antenna I have is a 7 element mono band LogYagi with very high gain and coupled to a 1.5kw amplifier, an excellent ground system is an absolute requirement to avoid RF feedback into the transmitted signal and also avoiding RF burns.  I have a few hundred feet of 1/4 inch diameter solid copper running in damp soil about 8 to 10 feet under ground and this ties back into the 'radio shack'.   I use this same ground to ground the cable TV line which is full of 60 hz. noise and my main audio system.  This is what I connected to from the PH 10 which eliminated all noise from the audio circuit. 

Also, I usually run 47K not 22K.  Only on some recordings do I find the 22K to be preferable, but that is not too many of them.

OH, one other comment on the AT20ss and 47K ohm... I have a NOS stylus installed with probably not much more than 50 hours use.  Its very fresh, so it has a lot of upper end compared to a well used stylus, that probably is playing into some of why I like it at this setting.

Slim
loading MMs is about both C and R.  Optima are different for every cartridge or certainly every brand of cartridge. So for sure I would not say that every single MM cartridge will sound better at 100 K ohms. I have found that my old Grado TLZ and my Grace cartridges definitely do sound better with 100 K load and no added capacitance, over and above the cable capacitance and the input capacitance of the phono stage. Testimony from others like Chakster and Raul leads me to believe that 100 K might be best for the majority of MM cartridges, but certainly I do not know that for a fact.  Also, it’s not only about opening up the high end. The entire audio frequency bandwidth  comes through with a greater clarity for cartridges that prefer 100 K to 47K. Like I said if you keep lowering resistance below 47K there is the risk of rolling off your high frequency response. Even your own testimony suggests that the beneficial effect you perceive at 22K may be related to rolling off hf. Like a tone control.

Thanks for the clarification regarding your grounding system. Even with your more detailed description, however, I am not sure it’s a good idea to attach your phono stage ground and your general audio ground to the ground system you use for your other devices. I guess only your experience can vouch for that.

I've mention At 20SLa just because it is the closest to your SS which must be better )never had that one). However, i have AT-ML180 OFC and OCC and both are fantastic with 100k Ohm. Grace F-14, Grace LEVEL II and Victor X-1II are superb at 100k Ohm, but all of them are also OK at 47k Ohm, so no problem with that. All those carts have extremely wide frequensy response and the most advanced cantilevers/styli. 

I'm just trying to say that adjustable MM phono stage is a good idea, fixed MM phono stage is not as good as adjustable for those who own too many cartridges. 

I totally agree with both of you; adjustable input for MM is critical.  As said above, I have found for the AT20ss the 200 pf range just works out great (again with my audio cables) and the 22K or 47K ohm input is also very nice.  Just that from what I am hearing, I am not sure I'd go much higher than 47K as I can definitely hear a little too much accentuation on the upper range.   I might have to send a note to Italy and inquire if I can get a schematic of the boards and see where I could couple a series 47K resistor in line which would put things up near 100K just for fun.  Or perhaps I could use one of the loading resistors on the input RCA's which might do the same thing.  It could be fun to play with.

As far as grounding goes, I just want to make sure that my ground is a top notch earth ground and no worries, I do not run the audio system while running the on air transmitters :)