Just curious, what exactly are you trying to produce? I could only find references to the Kolbe reaction being used to convert phenylalanine into meth.
Also, Post 75904 (missing)
(jim: "Re: Kolbe synth", Chemistry Discourse) claims that you cannot use silver electrodes. Nobody confirmed or denied this claim, but it might be worth looking into. https://www.thevespiary.org/rhodium/Rhodium/chemistry/electro-amph.txt (https://www.thevespiary.org/rhodium/Rhodium/chemistry/electro-amph.txt)
specifies platinum as the preferred material for the electrodes.
I have little to no experience in chemistry (much less the Kolbe reaction), I'm just trying to learn about a thing that is entirely foreign to me by attempting to help others. So if I have said something completely retarded, or this post is of no help whatsoever, that is why.
If it's any help, and you can read german, here is the basic procedure swim followed: http://www.ph-weingarten.de/homepage/faecher/chemie/kolbe.html (http://www.ph-weingarten.de/homepage/faecher/chemie/kolbe.html)
And, while swim doesn't have the lit source available, swim has read before that the electrode material isn't terribly important (obviously Pt is better than Ag, but what'cha gonna do? Even that may not be true, since the anode really doens't react or do anything in the reaction, I imagine it could be anything [I've seen it be crazy stuff like diamond or Mo in some other places, I think...] One must consider the pocketbook). Personally, I think his mistake was that the intermediate wasn't able to be substituted with an electron withdrawing group (such as I, from PI3 perhaps.....). The colour change seems to indicate that an indicator was formed, and just by glancing at other indicators, many seem to involve an aromatic alcohol (present) as well as some other area of unsaturation/pushable electrons conjugated with the aromatic compound (which would be present if an alkene were formed, rather than an alpha-methyl group).
As to what swim is trying to make, well, A,N,N,O-tetramethylserotonin seems like it could be interesting, no? But should this process prove viable there is no reason why AMT and amphetamine couldn't also be readily synthesized by this method. Ultimately though, it's just playing with chemicals, no intent of injestion, just playing a little god.