Aesthetix vs. Allnic vs. ARC ph7

Sbrown, Changing the output coupling caps in my Janus made a profound difference in sound. I happened to have some 2uF polystyrene film and foils in my stash, and I used those.

How did you find space to fit the Dueland capacitors in the Io? Unless it affords a lot more room than does the Janus, I would doubt that they fit. I used 300V Vcaps in the Janus. They're only a little larger than the stock polypropylenes.

Dear SBrown,
I don't blame you for missing the answers to your questions in reading my rather dense post. The Janus uses only two capacitor values in the coupling applications: 0.22uF and 2.0uF. I replaced the two 0.22uF caps used in both the line stage and phono stage sections with 300V-rated Vcaps (requires four capacitors, total). The choice of 300V rating was determined for me by the fact that they are only a bit larger than the OEM polypropylenes, whereas the 630V-rated Vcaps are quite a bit fatter and longer. I replaced all of the six 2.0uF metalized polypropylene film caps with 2.0uF polystyrene film and foil capacitors. The latter are a bit larger in diameter than the originals but they do fit. I changed nothing else; the tubes are still the OEM ones. The transformation in sound was quite remarkable, more obvious than expected.

I do also have a new tube set from Jim McShane, but I have not installed them as I see no reason yet to do away with the OEM tubes.

Good point, Al.
Just found this info from the S'phile review of the Rhea:
"The preamp's output impedance was a low 110 ohms at 1kHz from the balanced jacks, this rising inconsequentially to 156 ohms at 20kHz but, more significantly, to 3846 ohms at 20Hz. This rise at low frequencies is due to the limited size of the coupling capacitors and implies that the Rhea must be used with a line stage having an input impedance of at least 30k ohms if the bass is not to sound lightweight. The output impedance from the unbalanced RCA jacks was a high 2k ohms across most of the audioband, but as this rose a relatively small amount at 20Hz, to 3.05k ohms, the preamp's tonal balance will be less affected by the line stage having a lowish input impedance."

So to those who own the Signature version, there is a logical reason why it would have a superior bass response compared to the standard Rhea. This is an easy upgrade, however. The Sig version should drive 10K ohms ok though.

Sbrown, It's a matter of semantics. "Output" capacitors can be said to be performing a coupling function, since they are in series with the linestage input (on a phono only stage).