Update on Pa's new F5?

Separate front end V rails?

lhquam - A parallel output device (even just 2 pair) F5 with cascode front-end and P3, running at 35-40V rails would be an excellent higher-power, low-distortion amp. Basically a F5T “1.5” because no diodes.

I am sitting on 4 of cviller's F5 boards which have optional cascoding and dual output transistors, and when I put them together I will add P3 as well. But I got sidetracked with adding ps caps and biasing up an Adcom GFA-5200 to 20W of class A and an Adcom 5400 to 4W, and from these experiences now have one additional demand on my future F5:

I want the F5 front end running higher V rails than the output stage rails. On the '5200' the front end rails are +/-54V and output rails +/-42V, so 12V higher.
Are separate front end V rails possible to achieve on the F5?
Is 12V the right margin over the output rails to get full swing?
 
Nelson killed the magic! Haha But why more body? F5 for me was always too clean and thin sounding amp even when it was (still is?) the lowest THD FW amp, doubling outputs fixed it…. But who am I to question the wizard though 🙂
 
Spice sheds not much light on the sound difference ......
 

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Hm, when I double the outputs every pair has 1.25A so 2.5A total for the amp.

OLG gets about 6dB higher for doubled in Spice compared to standard. Is this a value to be expected?

if you double Iq, xconductance is really twice previous (same being in function of Iq per device)

if you stay at same sum Iq, xconductance is decreased for each because Iq per each is decreased

how much - either measurements or calc from graphs readout

though, no ready available graphs for so low current range, except if someone published specific ones (no from manufacturers)