Thank you, so that would be big.
I found
this 1.21 C/W Heatsink for 220 packageat Farnel.
But I would rather be safe and go for 1 C/W.
Maybe if I boost it's performance with a
£1 fanrun at half voltage for quietness?
The purpose is to use these chips as constant current power supplies to precede the shunt regulator. Apart from the possible sonic advantage, they have a practical advantage of less sensitivity to supply voltage variations.
I suppose the ideal would be to only aim to use 60v of headroom across the chip but put in place heatsink capability for the full 125v.
Obviously for a CCS anode load of the first VA stage of an amp the current is miniscule and the heatsink requirements of no consequence. It is the power supply application which I am eyeballing this chip.
As I said before it is a modern day Barrister to a power supply designer, i.e. offers great flexibility.
The other appeal about the chip is that it is no longer a poor man's CCS which the usual 3 legged VR chips would be compared to the efforts of the likes of Gary Pimm.
"Excellent performance specifications,
superior to those of most bipolar regulators, are
achieved through circuit design and advanced
layout techniques.
As a state-of-the-art regulator, the TL783
combines standard bipolar circuitry with
high-voltage double-diffused MOS transistors"
If it does tun out to have the "right" internal complexity and materials choices it could prove to sound good and save an awful lot of faffing around that most of us never achieve normally.
Time someone in the solid state wold amongst us evaluated it against such benchmarks as the Pimm stuff.
I can't do that, but I can make one and see if I like it. Not a lot to go on but things have to be pretty good before I like them.