popbumper Posted January 11, 2006 Share Posted January 11, 2006 An interesting challenge - The 1976 Cornwalls I picked up about a year ago still sit idle, and I am finally getting around to starting work on them. The cabinets I built also sit idle, and the "hang-up" has been the lack of crossover networks - of course I do not wish to settle for the inadequate stock units. Over the past several months I gathered up parts to build Al's Cornwall B replacement network, and figured it would be interesting to see if I could fit the components on my K-stack PCB's. Dean makes a beautiful point to point rendition of this network, and I saw it as a challenge to adapt the components to my PCB's. After about an hour of working on these tonite, they are coming together nicely, but the small real estate of the boards makes for some curious geography of parts since there are, well, quite a few!! I have not finished these yet, but probably will have something together over the next week or two, at which time I plan to do a critical listening session. I am looking quite forward to hearing these units. Just so I am clear, I am building these units for my own consumption as I am aware of the agreement that Al and Dean have regarding "trademark". I just wanted to share what I am working on, and will share pics of these once they are done. Chris Quote Link to comment Share on other sites More sharing options...
Deang Posted January 11, 2006 Share Posted January 11, 2006 I've been tempted to substitute that 62uF Solen in the woofer section with an electrolytic -- I just can't find any yellow ones. When you get done, you're going to have lower those into the Cornwalls with a crane. Quote Link to comment Share on other sites More sharing options...
BiggerIsBetter Posted January 11, 2006 Share Posted January 11, 2006 I am also looking at building those for mine, I just ran the number to get the parts yesterday. let us know what you think of the sound. Anyone like to offer the component value changes to account for the K401 horn, i.e. move the mid and low xover points to 400hz? Quote Link to comment Share on other sites More sharing options...
popbumper Posted January 11, 2006 Author Share Posted January 11, 2006 Dean: Please clarify if you would - the circuit calls out a 39uF on the woofer circuit, not a 62uF - maybe you were thinking of something else (or maybe I have to stop drinking so much cough syrup). Lemme know, thanks! Chris Quote Link to comment Share on other sites More sharing options...
IB Slammin Posted January 11, 2006 Share Posted January 11, 2006 I am also looking at building those for mine, I just ran the number to get the parts yesterday. let us know what you think of the sound. Anyone like to offer the component value changes to account for the K401 horn, i.e. move the mid and low xover points to 400hz? .. "Anyone like to offer the component value changes to account for the K401 horn, i.e. move the mid and low xover points to 400hz?" As I understand it, that is not possible with that circuit. (?) Terry Quote Link to comment Share on other sites More sharing options...
BiggerIsBetter Posted January 11, 2006 Share Posted January 11, 2006 "Please clarify if you would - the circuit calls out a 39uF on the woofer circuit, not a 62uF" There is an update within the zip file on Al K's site. The values in the LP were changed due to some realization on woofer impedance. Bummer if that circuit can't be changed to a 400hz xover point. I was just going to use ratios to adjust it.... Quote Link to comment Share on other sites More sharing options...
Deang Posted January 11, 2006 Share Posted January 11, 2006 ! Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted January 11, 2006 Share Posted January 11, 2006 Dean, A nonpolar electrolytic in place of the 62 uF would probably work ok. I suggest a 30+33 uF mylar pair would save some money and certainly would work. Look at the Solen Bennic brand caps. AL K. Quote Link to comment Share on other sites More sharing options...
popbumper Posted January 11, 2006 Author Share Posted January 11, 2006 Wow - sure glad this came up the way it did - I had ordered all the "old" parts and was in the process of populating the boards. I would not have known of the changes, thanks Dean!! Chris Quote Link to comment Share on other sites More sharing options...
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