Made some more tweaking but still not 100% satisfied. I improved the grounding scheme (took power section ground out of the bus) with good result on the noise, but still I couldn't capture the tiny & bright sound I was after for this amp.
Afterwards - by some more analyse of the videos - I think that the 8" 8 Ohms Vox Bulldog designed for the Pathfinder is the main responsible for some AC4 clones that I hear sounding pretty close to the original.
In contrast, the Celestion eight 15 (I was planning to replace the "too tweedy" Jensen C8R with) is advertised as "sounding big" which is not so much what I am after (plus a sensitive speaker will increase the noisefloor).
Now my options are:
0. (but the Celstion eight, which remains my default option)
1. find a 8" 8 Ohms Vox Bulldog speaker, which seems unlikely in my country, or
2. use something else - maybe a wideband or hifi-alike speaker as an alternative.
I read on Thomann's comment section that some people erred at using (example given:)
Visaton BG20 speakers for their guitar combos but I could find no more information about that.
I am very termpted to give it a try - because of Thomann liberal's return policy and because I am partial to neutral speakers - but I would appreciate to read some more about the subject, eventually...
And, oh yes: it's all in the spirit of a cheap small pratice amp...
