Classic 30 mod: which jumper disconnect ?

[ricci]

...to remove the feedback loop from the 1st preamp tube?
http://img175.imageshack.us/my.php?i...aveyc30qy5.jpg

[Enzo]

What feedback loop? The only thing remotely resembling a feedback loop is the coppertraces on the board are drawn with extra fingers next to each other. This results in a couple pf of capacitance of NFB, but it lops off high freqs way above the audio range. It is there to reduce RF. Only way to remove it would be to grind the copper trace material away.