Quite interesting set of responses on the TC100. My issue with the amp was that it kept losing output volume. It got to the point where the TC50 had more power than the TC100 at 100W. It was all due to the instability of the Chinese 12AT7. The JAN/Phillips 12AT7 made a huge difference and I restored that volume I had when the amp was new. Odd that I prefer the Chinese 12AT7 in the RA100 as it has a similar design. Tried the JAN/Phillips in the TC50 and that did not change anything.
If I have not stated before, the 12AT7 tube V5 is always in the signal path. The send circuit is a cathode follower with low output impedance and the recovery stage is the other triode of that tube. The FX on/off circuit is just a relay that shorts the send to return when something is plugged into the FX loop jacks. If you do not plug anything in, the return jack has a shorting switch to connect to the send so it is bridged internally. Turning on the FX loop or turning it off should not have any change in character. Just insert a jumper cable from send to return and see if that does make a difference when you turn on the loop or turn it off.
My cables are 10ft as well. I have several sets of this cable. I have yet to have issues in tone suck with any amp unless the gear is not compatible with line level signals.
https://www.sweetwater.com/store/de...trument-patch-cable-10-foot-straight-straight
I mostly use Strymon stuff as that was the only brand that worked with the Mark V90 FX loop without getting overloaded or suffer major tone suck or compression. I still have some of the units I experimented with that did not work well with the Mark V90: TC flashback triple delay, and Line-6 DL4. The TC unit was just a shift in tone, the Line-6 was more of a buffer overload issue as it compressed the signal so bad it had no detail in the effect. I did try something other than Strymon, a Source Audio Ventris. Its specs stated it would work with line level signals +8dBu. However, when I used it, the output level seemed to drop, it would go back to normal level if I turned it off. This issue was not just with the TC100 or TC50, I had the same issue with the JP2C and that signal level is not line level either. Perhaps I need to update the firmware or do something with the NEURO interface to correct the output. It is a decent unit, just did not maintain unity between input and output.
Some of the FX units may have some sort of configuration programming through a downloadable resource. If the input and output are not self adjusting to maintain unity in signal levels, you may have to adjust some parameters of the unit using the proprietary program to configure it. I need to see if I can get the Ventris to work better. If I could fix that drop in volume issue it would be a cool fx pedal to use.
