from Sphinx to Cronus Magnum?

Hi audiophiles,

Currently, my system is a Rogue Sphinx amplifier, a Rega Apollo-R cd player, a Rega RP6 TT with exact cartridge, and Kef LS50 speakers. I am enjoying this very much, but have been wondering about upgrading to a Cronus Magnum at some point. In part, I am curious about a tube amp (have never had one) and I also am interested in doing the best I can by these great speakers.

Has anyone made this move from Sphinx to Cronus Magnum? I'd be curious about any observations.

Also, is anyone running the Cronus Magnum with the Kef LS50s? What do you think of the combination?

Finally, if I eventually want to upgrade to an external phono stage (and assuming I stay with the Exact cartridge), would I be better off with a Rogue Triton or a Rega Aria? The half size of the Rega is appealing because I could slide it into my rack next to the Apollo-R without adding a shelf, but I could add a shelf if I had to.

Thanks for your thoughts! Happy Thanksgiving!

Hi Margot,

I can't speak to the intrinsic sonic characters of the Sphinx or Cronus Magnum. But given the impedance curve of the LS50, shown in the first figure here, the interaction of the speaker's impedance variation as a function of frequency with the higher output impedance of a tube amp, relative to the negligibly small output impedance of the Sphinx and nearly all other solid state amps, will alter the sound in predictable directions. Specifically, a tube amp will provide greater emphasis to frequencies at and around speaker impedance peaks (especially in the mid-range in this case), and lesser emphasis to frequencies at and around impedance troughs (especially in the mid-bass region in this case).

Those differences will probably be more pronounced connecting to the Magnum's 8 ohm taps than connecting to the 4 ohms taps, since the 8 ohm tap of a tube amp will have a higher output impedance than the 4 ohm tap. Which tap will be subjectively preferable, though, is of course not predictable, and you should try both if you purchase that or any other tube amp having multiple taps.

Also, keep in mind that you will be able to alter and tailor the sound of the Magnum significantly by substituting tubes of different makes and vintages.

Happy Thanksgiving to you and yours as well. Best regards,
-- Al
Why not upgrade to a Brio R? If you look at the million page LS50 thread on AudioKarma it appears that is the match made in heaven and completely does justice to the speakers.

Taking off on what Al said there is not much in the way of lab tests on the integrated, but if we take a leap of faith and assume that it is comparable in output stage to the Titan Magnum the test is here
and the output impedance measures a very moderate half ohm on average.

On the good side this will mitigate frequency response variations somewhat due to the voltage divider effect. On the other hand it indicates a reliance on feedback and, no doubt, one will either be comfortable with that, or not.

Anecdotally, there are a number of people reporting good results with tube amps on the AK thread, but YMMV. Then again some people listen to Klipshorns with Phase Linear amps so anecdotal reports may not be all that they are cracked up to be.
May I suggest adding a good subwoofer?
A good musical foundation, or "base", gives your ear/brain something to compare the mid/highs to for a more natural perspective.
Really good bang-for-the-buck.
Thanks, all, for your insights here which are helpful! And, Al, I love the pictures of your listening room. Looks amazing!

cheers, Margot