"New" crossover in "old" Theater 4's [message #52624] |
Sat, 13 September 2008 10:41 |
GarlandGarland
Messages: 60 Registered: May 2009
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Just completed the rebuild of the crossovers to Wayne's new design for the 4 Pi and am quite impressed with the sound. I'm hearing things I never heard before in favorite recordings and the musical flow ("PRAT") is astounding! Mid-bass is perhaps too full and bloomy but I'll wait for break-in before true evaluation. So far -so good! -Thanks, Wayne!!! Garland
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Re: "New" crossover in "old" Theater 4's [message #52627 is a reply to message #52624] |
Sat, 13 September 2008 22:43 |
jimbop
Messages: 60 Registered: May 2009 Location: Colorado Springs, CO
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Garland, I was recently thinking about this same upgrade for my Theater 4's, although I haven't compared the two schematics yet. How many parts get changed? Can you give me a ballpark figure on the cost? Jim Dombrowski
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Re: "New" crossover in "old" Theater 4's [message #52640 is a reply to message #52627] |
Mon, 15 September 2008 14:09 |
GarlandGarland
Messages: 60 Registered: May 2009
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Hi Jim, I used alot of parts I had in the "junk box". All I needed to buy was the Jensen foil 1.5mH coils which I got from Parts Express for about $50. But you can get the 6.8uF caps, the 20uF caps and the 1.5 and .5Mh coils for less than $100 at P.E. I used GE motor run caps which are the best I've heard for the money but kind a bulky. My X-over mounted externally on the rear panels measure 6in.x 15in.x 4in. G.
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Re: "New" crossover in "old" Theater 4's [message #52641 is a reply to message #52626] |
Mon, 15 September 2008 14:27 |
GarlandGarland
Messages: 60 Registered: May 2009
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Well Bill, I been OK but actually am coming off a year-long withdrawal from audio obsession and am feeling really good but am beginning to slip....! The soldering iron still works but i had to refresh myself on Ohm's Law. My work table is still covered with kids'stuff but I managed this crossover rebuild with out blowing up and the sippin' whiskey was poured only on the successful completion of the project to the accompaniement of Ben Webster and Dave Van Ronk. Your comments on the brightness- clarity issue elsewhere reminds me of the tweaking that i've done with the compensation circuit on the tweeters. That would be the value of R1 I believe. I started the new crossover with some 20 ohm resistors and found the sound just too laid back, then 15 ohms went in and now the sound was a bit hot in my room, but at last I tried 16 ohms as spec'd and MMMM, just right! You might try a higher value and see what you get! The biggest difference in the sound in my room was how forward the performers were in the soundstage. G.
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Re: "New" crossover in "old" Theater 4's [message #52648 is a reply to message #52642] |
Tue, 16 September 2008 14:46 |
GarlandGarland
Messages: 60 Registered: May 2009
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Hi again Jim, The GE caps are for the 20uFs; ie. C- 3,4,and 5. C1 is a mess of parallel caps which are based on a .39 uF Jensen oil cap. C2 is a 6.8 uF Solen metalized polypro. Try the motor runs; they are readily available and sound good. Garland
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