40W vs 20W - tone difference?

Hi all, I'm new to H&K and delighted so far with my GM40 and 212 H&K V30 Cab.

I have a question about the Power Soak. Tone-wise will there be a huge difference running at the full 40W using a lower Master volume (25%) say versus switching to 20W with the Master a little higher at around 50%?

I know the pros & cons at running 20W (saving tube life, but more heat etc) but not sure what the trade offs are in terms of overall tone & sound. I haven't been able to try this out myself at volume yet so just throwing it out there....

Right, probably should have looked at other posts in the forum before posting this. There's a great deal of live comparisons done with the GM36 (see https://handkusers.forumotion.com/t155-master-volume-settings). I think the sweet spot is to keep the Master around 12-noon if possible for crunch/leads so I'll be trying this at 20W. And also going from 40->20 W doesn't use the Power Soak, just switches off 2 of the 4 power amp tubes which makes sense.

To my ears, remarkably, the GM40 doesn't really have a 'sweet spot'. It sounds better loud than it does at bedroom volume, but the tone is generally very consistent.

Personally I just run the clean sounds at 40w and the distorted sounds at 20w, that seems to work perfectly.

I can't comment on GM40 tone I'm afraid but on a technical note the additional heat question with the power soak is a bit of a non-issue. You're right, it doesn't make any difference from 40W->20W where one output pair is removed, but even from 20W->5W->1W where the resistors are switched in you are only dissipating a maximum of around 19W extra and it's even less than that in real life terms as the guitar signal is so transient, that means it's just not like a steady state sine wave signal at all. If you average out the gaps in the signal and your playing they drop the actual dissipated heat down much lower. It really doesn't make that much difference to an amp in a well designed metal enclosure which conducts heat out as well as convects it as the H&K models do.