Who uses ADS Speakers

@au_lait, it is likely that you are going to have to live with a roll off at 40 Hz with these speakers. However, it is likely that they are capable of nice tight articulate bass. The printed circuit board seriously compromises performance. If you are able to build a completely new cross over, as I did, you can eliminate the switches that enable bi amping and provide tweeter attenuation. Those switches seriously compromise performance. They are cheap and are now 40 years old. Mine completely disintegrated when I tried to desolder them. I also eliminated the tweeter protection, which made an easily audible improvement. If you don’t drive them too hard, you can probably get away with this. You will probably also get some improvement in low frequency quality by replacing the internal wiring. I used Duelund tinned copper for this.

One of the things I really noticed after my crossover work is the midrange beauty. Very smooth and refined, as compared to my other speakers, both of which use a 7 inch mid-range.

I would encourage anyone who likes the 1290’s and has spent the money to have Richard So recondition the drivers consider a rebuild or redesign of the crossovers. If you are handy with this sort of thing, a complete crossover redesign, like I did will afford a much improved speaker. However, for those who are less ambitious, simply replacing the stock resistors and caps will make a big difference.

Additional information.  I considered replacing the inductors, but decided against it. Doing so would significantly elevate the cost of the project and probably necessitate using an external cross over.  I also thought about but did not go for an upgrade on the binding posts. 

I bought these speakers used about 15 years ago, and they were in very rough shape.  The cabinets were badly scratched and the grills were really bent up.  Had the cosmetics been better, I probably would have done an even more radical crossover rebuild with better inductors for those that are in series with the drivers, where the correct inductor values could be sourced. 

I got as far as I could with this rebuild last winter, but put the work on hold to attend to some other goals I had for this last year.  I don't enjoy the cabinet work that much, so its easy to push that kind of thing aside.