stevehoover wrote:
Just for my own edification, where does all the "briteness" come from in this amplifier circuit?
The EL84 power tubes are naturally quite bright. So in my experience most EL84 amps have a tendency to be somewhat bright. So Vox amps usually have the Cut control to compensate. Marshall 18W amps have 8.2k grid blocking resistors on the power tubes, which also helps somewhat.
HarmonyoftheSpheres wrote:
Perhaps there are other mods in the TC-15 that compensate, such that the changes you're talking about would not improve but degrade the TC-15?
It seems that the TC-15 does indeed have some extra magic over the regular Lightning. Certainly the EF86 channel is a huge extra. The TC-15 also seems to yield some great tones without the choke, which the Lightning has, and you have the additional flexibility due to the 5k/8k OT.
However, at some point it starts to become more a matter of personal taste. For example, I happen to like the thicker tone you get with C1=5nF, but that doesn't mean the next person would. It all starts to get quite subjective.