Active Loudspeaker!

A bit of an anti-climax, perhaps, but I've now got an active Boston A100 :-o.

I removed the original back terminal plate, hot glued onto the inside of a hole in the back of the speaker. I then removed the fuse and terminals from the board, so I could reglue it back inside the box to support the original crossover components. I then wired up a DPDT switch and the new "biwire" terminal block, so that the speaker can be used active of passive at the throw of a switch. The hole in the back of the speaker was too wide for the new block, so I filled it with a piece of 18mm chipboard (actually from some old G-Plan furniture shelves we scrapped a few months ago! Very decorative...).

Taking out the old terminal panel

Refitting the old panel with the original crossover components

The original hole filled to fit the new terminal block

New terminal block, with separate woofer/tweeter wires, also shows active/passive switch

Setup with Safire DAC, Myst stereo amp and speaker

The original crossover is shown below diagrammatically - I used an online tool which is a bit pants but hey...

Original Speaker wiring

And this is the revised version, which allows the woofer and tweeter to be completely separate.

Active/Passive switching circuit

Except that now I look at that, I see a massive inductor wired permanently across the woofer terminals... Albeit through a few caps and a resistor. Damn... Will this have an effect? Arguably, I should disconnect the entire old crossover network. That requires another or different switch. Later - I have other difficulties!