Hey Bob, I have Mick making me a Pre as we speak (or in que at least, lol). All Cortese models are Phono integrated pre's. The price difference ($4K / $7K) is whether or not the phono is a standard CR or the more expensive LCR version and the $500 difference between those is whether or not the chasis is Copper/Chrome or Steel. Having the phono (Cortese) is not going to make a difference in heat vs a Chardonnay, it will be negligible. The phono tubes are rated at ~10k hours as well so they will most likely outlive all the other tubes in use too. If you don't need the phono section though, then you need to look at the Chardonnay or Cabernet. After discussion with Mick, I was led to believe that the difference between the 2 is in the capacitors and iron (transformers/chokes) in use, the circuit is pretty much the same. The power supply I believe is pretty much the same as well except the Chardonnay has the Tube Regulators located on the preamp box (PS box has just the rectifer) and the Cabernet has the Regulators located on PS box (3 tubes). Biggest difference being the audio circuit components. He told me that the Cabernet, even with some more exp. componets is not necessarily better per-se, but a little different. Possibly a bit more nuanced I guess. Mick will tell you that all the magic is in the circuit design not fancy components, although he does use quality and nice components even in his cheapest builds. Hope this helps!