I took delivery of a Pass Labs XP-15 phono preamp this week. Biggest gains thus far are in noise floor, dynamics, etc. as it should be considering I was using the built-in phonostage on my Cronus Magnum. Rogue intimated their built-in stage rivals externals in the $250-$400 range.
Of course, there are tweaks to complete as well as break-in so I will reserve my critique for another time. There are tons of loading (47Kohm down to 10 ohm) and capacitance options (750pf to 100pf) available.
I am running a Soundsmith Zephyr MKII HOMI (47Kohm, 100pf-200pf) on a JMW 9 tonearms, VPI Scout 1.1, Zu cabling, Rogue Cronus Magnum Integrated (using for linestage pre and power amp) and Zu Soul MKII speakers.
You would think, "oh ok, you’re done. You have your load values so set it and forget it."
Of course I am knee deep in threads reading about how 47Kohm loading for MM or HOMI is vanilla and the conspiracy theories that surround it (companies want to make it as vanilla as possible because those with MM or HOMI do not want to tweak and/or invest in a pre with a lot of loading options such as those who invest in MCs. 47Kohm is an easy value to float as there are many variables in one’s system to consider.)
If you have experience playing with various loading and capacitance values with this preamp and cartridge or at least just the cartridge type (MM, HOMI) I would appreciate your feedback and or insight into how to find the optimal setting. I have adjusted the loads and listened and some of the differences are so minute it’s inconsequential (or maybe my hearing isn’t as finely tuned as it could be.)
The Pass Labs owner’s manual recommends starting at 100ohms, listen for an hour, then move down to 50ohms and repeat. When the sound deteriorates, move back to the last setting and that’s your optimal resistive loading value. Why such a large arbitrage between the recommended greater than/equal to 47Kohms (manufacturers rec.) and 100ohms (Pass Labs rec. starting point?)
Love all the options as you can use about any cartridge and you can really grow into this piece but this non-linear existence lends itself to more tweaking and critical listening.
Thanks.
