I really like this option:?
? ?- code is available -?
? ?- parts kits are orderable from a number of sources, including amazon (get it in maybe two days!), aliexpress, etc. search for AT-100. Could be as low as 21.xx from Aliexpress
? ?- testable outside of the amp (put varying loads representing your amplifier input on the output of the ATU100 to see how well they're matched)
? ?- I *think* some models actually show the values of L and C used to match so... you could make a fixed network if you like. Consider the price of the kit a "test instrument" for determining values for your manually switched network.
-Brian N9ADG
