Rega Apheta 3 Capacitance 1000pF???

atmasphere 1000pF is their spec. You can see it at the specs for their cartridges and their phono stages.  The phonos even are switchable to higher capacitances.  Cited often in reviews of their phono gear. 

@sumadoggie 

Sheesh. I didn't realize this is a low output cartridge. You don't really need any capacitance at all, the rules regarding low output cartridges apply at the link I provided. 
http://www.hagtech.com/loading.html
From that webpage:

The super-low self-inductance of a moving coil cartridge puts them in their own category. At such levels, the loading capacitance becomes relatively insignificant, with system bandwidth now dominated by inductance and load resistance.

In a nutshell, you're better off without it. Just go to the top of that page and drop in 1000pf into the calculator and look at the resulting frequency. Then take a look at the default inductance value; its way more than the value for a low output cartridge like the Rega. Go ahead and drop in a value of a magnitude lower inductance and you will see what I mean. You really do want that pf value to be as low as possible in this situation, putting the resonant peak at as high a frequency as you can. This reduces the possibility of the peak overloading the input of the phono section. To this end, you also want to use low capacitance cable for the tonearm interconnect, as this value is part of the peak. I really don't know what Rega is thinking here, but that 1000pf value is bad advice. If there is a variable I'm not thinking of, its certainly not obvious from the specs on their website.

Any LP has bandwidth to 40KHz or so although its rare to see actual information much above about 25KHz as microphones and tapes don't go much higher. This is part of how LPs are able to sound better than digital in many cases- it has more bandwidth.

Brother -

I have a Luxman EQ-500 paired with a Rega Planar-10/Apheta 3 cartridge. I do actually have an issue and it pertains to volume.

For other equipment I have a PS Audio 250 amp and the company's Signature preamp. I have no sound quality issue with the DAC or my CD player, both of which eventually run through my preamp - it's all great.

On the PS Audio volume scale of 0-100, the comfortable listening level for me is around 40; loud is 65; clear the room out is 80. That is, unless I'm using the turntable, in which case the comfortable listening level is 70. At that level, I can detect a small bit of fraying in the upper midrange.

The Luxman and the Rega and the Apheta all check out fine, but putting them together seems to cause a deficiency in my system. My guess is that, though all of the components are excellent, the Rega/Apheta and Luxman pairing is not optimal.

Any opinions out there? 

I don't know about the Luxman/Rega pairing, but that's interesting to hear.  Keith Herron gave me a full compliment of capacitance plugs to play with for the VTPH-2A/Rega P10 pairing.  I've been meaning to try them, but haven't mustered the energy yet.  Next time I throw on a record I'll listen for your upper midrange issue.