I have a few suggestions to make this modification a bit easier. These suggestions are my opinion only and are not meant to offend or belittle the author(s) of these mods.
The modification has you replace a bunch of polarized coupling capacitors with non-polar capacitors. An old trick that many audiophiles have used is to bypass the electrolytic capacitor with a small value capacitor. This is to negate distortions and series resistance of the electrolytic capacitors. You could use a 0.1uF film or MLCC (multi-layer ceramic capacitor) in parallel with these polarized electrolytic capacitors on the copper side of the board. Depending on the spacing of the leads a surface mount MLCC could work nicely. The capacitors to bypass are listed as C4, C6, C14 and C17 in the mod.
The mod also has you replace C2 with a larger value capacitor. The stock value of C2 gives the input a corner frequency of approximately 7Hz. Increasing the value only lowers this frequency. 7Hz is well below the range of human hearing so I really do not see the need to lower it further. Since it is an electrolytic capacitor you could bypass it the same way as the others with a small value film or MLCC to remove distortions.
Changes to D10 and R32 bring the power circuit up to the latest version of the CS-3.
Changes to R5, R36, C1 and C13 in the mod change the behavior of the tone and level circuits. This is where the mod is making the significant changes.
I know what I have said is considered blasphemy by some… but I will bet money that what I have suggested can not be successfully challenged in blind listening tests.
-Frank
