TW Express...just another clone!

[Cliff Schecht]

I wired up the 200 and 500 Ohm taps in my Express build with an A3801. I doubt I will ever use them but why the heck not?

Also, those extra taps are extra windings on the core which means you are going to have a higher leakage inductance than if you took off the extra windings. I could measure the A3801 on an LCR meter for leakage inductance and open circuit inductance for comparisons sake. I'm not 100% sold on extra leakage inductance and interwinding capacitance having a huge tonal effect though because IMHO the frequencies in which these parasitics hurt are above frequencies that us guitar players are interested in.

Edit: Of course these parasitics will also have effect how the transformer overshoots and less extra windings could lead to an amp with a quicker attack. The feedback on an Express (or any PP amplifier) will aid in getting a quicker response by helping the amplifier to settle quicker.