I just ripped the stereo and sound array boards out of my buddies SDA IAs for the crossover upgrade. They used to be mine and I still love them so I'm going to do the deed. My SDA 2s are next if there is a significant improvement. It was nspindels post that got me off my arse.
I do have a few questions. I have read quite a few of the posts on crossover upgrades, several dozen anyway, and I'm starting to get the gist but I haven't found a thread specifically for the SDA IA yet. If anyone can link me to a specific IA thread, that would be greatly appreciated.
So, now with the silly questions:
1) The schematics posted by DarqueKnight show a 3.5 ohm resistor with a rev.A note. These on my boards are 4 ohm. I will assume that a change to 3.5 ohms was the revision and use 3.5 unless someone can offer a reason to stay with the 4 ohm.
2) It seems that the cap values change with tweater upgrades. I suppose I will upgrade to the 198s if they are still the recommended favorite. The schematics for my boards show 12 uf caps on the tweeters. If I do go with the 198s, what caps should I order?
3) My boards dont seem to have polyswitches. Instead they have a pair of fuses. I think these need to go away. Any reason why I should not be done with these? (200w Hafler amp and reasonable -wife limited- listening levels).
4) I have a total of three of the 750 silver mica caps (that are often refered to as the bypass caps, I think). Do all three of these go away with the polyproplyene caps?
5) My stereo array board has a 0.5 uf ??? cap in parallel with the 4 (3.5)ohm resistor. The drawing says mylar but it looks electrolytic to me. Anyway, is polyproplyene the way to go with this cap and am I correct about the value? The drawing is a little hard for me to make out.
6) The 6501 driver caps are 27 uf. I'm going out on a limb here and assuming they dont change with a tweeter change. Correct, or did I break an arm?
7) I see the holes refered to as alpabetically labled. I'd love to see a drawing of the SDA IA board with these labels. Can anyone offer a link?
Finally, most of the posts I read concerning the tweeter upgrades are several years old. Are the 198 tweeter upgrades a cut-and-dry issue or should I give that some more consideration? I'm not saying cost is no object, but hey, it's not my money. I just want these babies to rock.
Thanks in advance.