Optimum MM cartridge loading

I see that most phono preamps do not have an adjustment for 100K load, which is what some MM cartridges like (such as the Grace F9). I only see 47K on the phono preamps I have looked at. Also being able to set the capacitance would be helpful, at either 100 or 150pF. Are there any "affordable" phono preamps that have these adjustments built-in? If not, how can I go about adding the desired loading and capacitance to an existing phono preamp? My Musical Fidelity X-LPSv3 has neither of these adjustments on it. I am open to replacing it with a unit that provides adjustments.

Our Liberty Audio B2B-1 can be fitted with any load you'd desire, standard is 47K ohm / 220 pF but if you'd want 100K Ohm 100pF or 150pF thats an easy change.

I'm working on a 3 input from the front adjustable Gain (4 settings) Capacitive Loading (6 settings) and Resistive loading (12 Settings) as well as Mono selection and Mute - The Liberty Audio B2B-2 (Direct from Factory Price $ 2495) Its still a little ways out till completion.

Meanwhile please read the writeup from the nice folks at Stereophile on the B2B-1


Dear Tube540: EAR 324 has all you need/ask for MM/MI cartridges and is affordable

Regards and enjoy the music,
Peter -- thanks, keep me posted on your phono stage. Raul -- thanks for pitching in. I was hoping you would see this and respond. After looking at the specs of the EAR 324 I can see this is one versatile phono preamp for BOTH MM and MC cartridges. Are there any others out there that have the 100K setting and adjustable capacitance like the EAR 324?
$6000 is "affordable"?

I guess I live on another planet.
I think the most cost-effective solution is the K&K audio TOTL phono stage, balanced version. For a bit extra you can have it with adjustable loading, and in my opinion, balanced phono is an advantage as well, for around $3K or less, in factory-assembled form, I think. Talk to Kevin Carter about your needs, and he can make it happen. (No affiliation.)

Further, if there's sufficient room on and in the chassis, it's no big deal to install adjustable loading for R and C yourself. The trade-off is said to be in terms of noise; the switch required for adjustment is going to introduce a very tiny amount of noise. I don't hear it even on my very high gain MC phono stage, so it really should not be a problem at the lower gain levels needed for MM.
$6000 is "affordable"?
I guess I live on another planet.

My thoughts exactly.
I guess if you compare it to the Boulders or Ypsilons out there, but those are not expensive; they are absurdly expensive. Either way, $6000 is certainly objectively not "affordable."
I suspect that the main reason the Grace F9 cartridges are spec'd for 100K (if indeed they are; more on that in a moment) is to extend their bandwidth to 45 kHz, for playback of the CD-4 quadraphonic recordings that were marketed in the 1970's.

Without detailed technical information, including the inductance of the cartridge, it's impossible to say for sure, but my guess is that with 47K loading their frequency response at 20 kHz would be rolled off to a degree that is imperceptible, if at all. And in fact some phono stages could very conceivably be happier, in terms of intermodulation distortion or other adverse effects, if less ultrasonic energy is sent into them.

I have the original brochure that came with the F9E I purchased in 1979, and it states "resistance (K): 30 to 100." I assume that refers to load resistance.

That said, I've always run mine at 100K, using the phono section of a vintage Mark Levinson ML-1 preamp. I haven't ever tried its 50K setting, which is selectable via internal DIP switches.

-- Al
Good to know about the upcoming Liberty phono stage. And Raul points out the EAR 324, which I have also never heard, but it has a good reputation. (Because of its very flexible loading, I have long been curious about it.) Then there is the K&K Audio one I mentioned. Any of these three can be had for half or less than half of $6000, and is an excellent choice. (I think you'd have to buy the EAR 324 on the used market to get within $3K.)