How make my Ayre system "warmer"?

Tubes don't add distortion until they are driven to distortion. Then they produce even-order harmonics rather than the odd-order harmonics that SS devices produce when over-driven. I personally own a tubed CDP, tubed power amps, and still enjoy very transparent(coloration and distortion-free) music. Some tubes, most generally from Britain (ie:NOS Mullard/Brimar), will provide a much "warmer" or more "sugary"(think, "glazed") coloration. Many obviously like that sound, as these tubes are very popular. Should you decide to add a tubed component to your system: Try some of those, and you'll probably be well pleased.

Tubes don't add distortion until they are driven to distortion. Then they produce even-order harmonics rather than the odd-order harmonics that SS devices produce when over-driven.

Then why, to cite what I admit is probably a somewhat extreme example, would the CJ PV15 line stage preamplifier have a thd spec of 1%? And why would some older ARC power amp designs that I can recall have thd specs of 3% or so? I'm sure a little research would turn up a considerable number of other examples as well, of highly regarded tube designs that have highish thd numbers, when operated within rated limits.

Obviously I was not referring in my previous post to the major distortions that would result from overdriving or clipping. Any non-linearity that occurs within the normal operating range of a tube or other amplifying device will result in small amounts of distortion, that may be sonically significant, especially in low feedback designs. Distortion that I believe would likely be a significant factor in what is perceived to be the particular tube or the particular design's sonic "signature."

Regards,
-- Al

You might keep in mind that tubes are not the only components in those pieces of equipment, and that designers of SS equipment have historically taken vastly more drastic steps to minimize distortion figures(ie: typically 40db of negative feedback), usually to the detriment of actual sound quality. Tubes are innately very linear(into RF frequencies), but unfortunately, provide relatively little gain/transconductance(low output current) and high plate resistance, hence the need for matching transformers. A great deal of the distortion inherent in tube amp design results from the use of transformer output coupling, not the tube itself.

Hi Tvad- Like most subjective evaluations with regard to this hobby: One person's candy will be another's poison. My first Mullards(CV 4004) were tried in a CAL Alpha DAC, when I had a much less resolving system than now. Their warmth was much more than I could accept even then, and they were quickly replaced with Tele's(ECC83's). No problem with soundstage, imaging, etc., but the coloration was simply not natural. I agree with your ranking, RE coloration levels: Brimar, Mullard and Amperex(the "pinched waist" I could probably live with). To me the Siemens and Telefunkens(whatever family of nine pin miniature) are the most transparent, extended and uncolored(natural) out there. Let me narrow that last statement to the pre-1968 tubes manufactured for the German Telephone Services, and branded as "Specially Selected"). One nice thing about Mullards is that, once tried, if not appreciated: they are easy to sell. I do love their voltage rectifiers though.