I just acquired a pair of 2.5R in really great condition, ribbons works although they look a little saggy in spots. One speaker does have a very small buzz only noticeable when I run tone sweeps.When I first received them the first thing I noticed was the obvious increase in bass in my room coming from MMGs. But also there seemed to be a lot of information missing in the midrange (crossover region) and some basic measuring confirmed this. After much researching I found a post where someone mentioned switching polarity of the speakers because Magnepan had wired them wrong. I tried this and to my surprise there was an improvement! I did another rudimentary measurement using Foobar2000s Mathaudio Room EQ and there is still quite the null in the ~700-5k region (5-10db drop). I normally EQ my response with a similar cut from 1khz-4khz but not quite so pronounced.
Which brings me to inquire what kind of tweaks to the passive crossover some of you have made. I've seen that some 2.5 seem to have shipped with 25uF caps in the tweeter circuit, mine are the 15uF variety that match the schematics online. I was thinking of trying some Dayton 25uF tweeter caps I already have on hand and maybe move the 15uF cap over to the panel shunt position. Anyone have any experience tweaking these networks or have one they've settled on? Can someone explain to me what the 2uF behind the connection plate is for?
I also need some help figuring out how to bypass the fuse and attenuator. I think I successfully bypassed the fuse on one panel but I want confirmation I did it right. What I did was move the brown wire on the fuse holder to the top where the resistors are. Thanks!
Edits: 04/23/15
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Topic - Magnepan 2.5R crossover help - kappa546 06:53:14 04/23/15 (14)
- RE: Magnepan 2.5R crossover help - RickeyM 19:14:11 04/24/15 (0)
- RE: Magnepan 2.5R crossover help - neolith 10:36:31 04/23/15 (8)
- OOPS! - neolith 19:23:33 04/23/15 (1)
- RE: OOPS! - kappa546 20:21:08 04/23/15 (0)
- RE: Magnepan 2.5R crossover help - kappa546 14:37:09 04/23/15 (2)
- I still don't get the point of the 2uF cap. - neolith 16:45:36 04/23/15 (1)
- RE: I still don't get the point of the 2uF cap. - Davey 16:49:30 04/23/15 (0)
- RE: Magnepan 2.5R crossover help - Satie 11:17:07 04/23/15 (2)
- RE: Magnepan 2.5R crossover help - neolith 19:08:10 04/23/15 (1)
- RE: Magnepan 2.5R crossover help - Satie 21:19:06 04/23/15 (0)
- RE: Magnepan 2.5R crossover help - Satie 09:24:19 04/23/15 (3)
- RE: Magnepan 2.5R crossover help - kappa546 14:43:01 04/23/15 (2)
- RE: Magnepan 2.5R crossover help - kappa546 14:46:16 04/23/15 (1)
- RE: Magnepan 2.5R crossover help - Satie 21:11:34 04/23/15 (0)