JSP Posted January 4, 2009 Share Posted January 4, 2009 I have a very nice pair of Cornwall II's that are all orginal, I am thinking that I may want to build new xo's for them, would any one knowledegable on the design question like to suggest a proper design? 1. Should I simply replace to caps with new of the same value? If so, what type (oil,foil, etc?) and brands? 2. Should I build new from scrach (my first thought), if so a schematic or design plan is what I need. I have built xo's before and it is within my scope of ability, just need a proven plan the works well for the Cornwall II. BTW, they still sound great, the only mod I have done is to put some damping matterial on the exterior of the horns, (reduced ringing at high volume) and refinish the cabinets with watco and tunge oil. JSP Quote Link to comment Share on other sites More sharing options...
Groomlakearea51 Posted January 5, 2009 Share Posted January 5, 2009 Personally (having several pairs...), I would do caps and then listen to them for a while before venturing into a crossover design. Attached is the B-3 crossover schematic for you to "ponder". Quote Link to comment Share on other sites More sharing options...
capo72 Posted January 5, 2009 Share Posted January 5, 2009 I would love to see someone develop an Extreme Slope Network for the Cornwall II's. I have always wanted to build Al K's design for my Cornwall I's, but I just do not listen to them as much as I listen to my Cornwall II's. Cornwall II ESN is something I would be very interested in. Jeremy Quote Link to comment Share on other sites More sharing options...
Deang Posted January 5, 2009 Share Posted January 5, 2009 There is a very small demand for high dollar networks for the Cornwall of any type. When I was Al's licensed builder for the Cornwall ALK, I only built one or two pair a year, and six pair total. The B3 network attenuates the tweeter (K-77), the Cornwall II network doesn't (K-79). IOW's, it's the wrong network for the Cornwall II. There's nothing "wrong" with the design of the stock filter, but the caps are nasty. I suggest simply replacing the 68uF with a Solen, and the 3uF and 1.5uF values with Auricaps. Quote Link to comment Share on other sites More sharing options...
Groomlakearea51 Posted January 5, 2009 Share Posted January 5, 2009 Whoops... sorry bout that'; here's the CW-II schematic. For some reason had the B series stuck in my brain.... Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 5, 2009 Share Posted January 5, 2009 Whoops... sorry bout that'; here's the CW-II schematic. For some reason had the B series stuck in my brain.... Changing avatars again????? Quote Link to comment Share on other sites More sharing options...
capo72 Posted January 5, 2009 Share Posted January 5, 2009 There's nothing "wrong" with the design of the stock filter, but the caps are nasty. I suggest simply replacing the 68uF with a Solen, and the 3uF and 1.5uF values with Auricaps. Dean, do you know if that can be done on the PCB or do you need to build a bread board to fit a 68uF Solen in there? Thanx, Jeremy Quote Link to comment Share on other sites More sharing options...
Deang Posted January 5, 2009 Share Posted January 5, 2009 Did they even have a PCB for the Cornwall II? If so, the 68uF won't make it -- way to big compared to the electrolytic it's replacing. I would build new from scratch on plywood. Quote Link to comment Share on other sites More sharing options...
BEC Posted January 5, 2009 Share Posted January 5, 2009 The earliest of the Cornwall IIs have this little number for the crossover. Later ones have the crossover on a circuit board on the back of the input terminal cup. Bob Crites Quote Link to comment Share on other sites More sharing options...
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