Guest 1080i Posted February 21, 2007 Report Share Posted February 21, 2007 Sorry if this has been covered before, but I did a search and can't find a good answer. I have opened up 3 small Advents (out of 4 I have)to rebuild them, caps and surrounds. So far, all three crossovers are different. Ignoring the parts that are the same in them:#1 from 1975 has a 5uF cap in parallel with a 3 ohm resistor.#2 from 1975 has an 8uF cap in parallel with a 2 ohm resistor.#3 from (I forgot when) has a 4uF cap in parallel with a 3 ohm resistor.I suspect #4 will be still different.All four have orange tweeters.What's going on? What is the "correct" value of these parts? What do you think I should do? Pick one and make them all the same, or leave them different as they are?Thank you. Link to comment Share on other sites More sharing options...
Carlspeak Posted February 22, 2007 Report Share Posted February 22, 2007 >Sorry if this has been covered before, but I did a search and>can't find a good answer. I have opened up 3 small Advents>(out of 4 I have)to rebuild them, caps and surrounds. So far,>all three crossovers are different. >>Ignoring the parts that are the same in them:>>#1 from 1975 has a 5uF cap in parallel with a 3 ohm resistor.>>#2 from 1975 has an 8uF cap in parallel with a 2 ohm>resistor.>>#3 from (I forgot when) has a 4uF cap in parallel with a 3 ohm>resistor.>>I suspect #4 will be still different.>>All four have orange tweeters.>>What's going on? What is the "correct" value of>these parts? What do you think I should do? Pick one and make>them all the same, or leave them different as they are?>>Thank you.The 'correct' parts are the ones that make each speaker sound great. Listen to all 4 and let your ears decide what's right.It's all about the musicCarlCarl's Custom Loudspeakers Link to comment Share on other sites More sharing options...
Guest sbalfour Posted February 25, 2007 Report Share Posted February 25, 2007 Assuming all the parts are original, you might check the tweeters(DCR, impedance and resonance). If there are any differences, thecrossovers would correspond to those. I think the Advent tweeter(same as in the Large Advent) underwent a revision which took itfrom 4 ohms to 3.1, though I think the revision was in 1971. Forcomparision, the Advent Large crossover underwent 4 revisions, notincluding that for the New Advent, which was entirely different.One was a manufacturing economy, one was to protect the fragiletweeter, and two were apparently design concept driven.The parallel cap/resistor is a high frequency boost, equivalentto the "extend" position of the contour switch on the LargerAdvent. The differences you note appear to me to be fiddle-faddling. The larger cap (8uf) and smaller resistor (2ohm) willgive a slightly smaller boost cutting in at a little lower frequency.The smaller Advent was known for having a lifeless lower treble,so maybe they were attempting to remedy that. However, the SmallerAdvent loudspeaker was discontinued after 1975, so the change wouldhave been short lived. Stuart Link to comment Share on other sites More sharing options...
Doug G. Posted February 26, 2007 Report Share Posted February 26, 2007 Actually, the smaller Advent tweeter was not originally the same as the large Advent. The magnet structure was smaller to match the efficiency to the smaller Advent woofer. The magnet is 2.5 inches square rather than 3 inches square as in the large Advents.I think that they may have changed this in later production units, however, making them the same as the large Advents.Doug Link to comment Share on other sites More sharing options...
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