1, Amp fuse

Read more on the Acoustat 1 in our home audio section

Vince Cascone2007-01-19 02:20

I have a pair of model ones that i love. Just the other day, one of them blew a fuse in my xl600 hafler. Traced it down to what appears to be a coil or choke in the subwoofer that was burnt. It is connected to the postive terminal in the subwoofer. It was letting midrange into the woofer and blowing my amp fuse. Is this part available. It has numers on it but no manufacturer infor.. Your input would greatly be appreciated. Thank you Vince


Andy Szabo2007-01-20 17:16

Let me say first that I doubt the fuse blew due to a failure of the crossover coil. Rather, due to very large amounts of power being applied, the coil got hot enough to burn, and then the fuse eventually blew. The fuses in the speaker should never be more than 5-amp slow-blow. At that value, very little protection if afforded, and personally, I recommend a lower value. If the coil is just a bit scorched, it may be still okay. If it is seriously burnt, then replacement is in order. For very early production Model One\'s, with only a coil and capacitor in the crossover, I do not have a record of that coil\'s value. If your crossover has a coil, two capacitors, and a resistor (per side), then you have a much improved crossover used in all but the earliest Model One\'s. That coil\'s value is 4.5mH and 4.3 ohms (air core). Most of the available ready-made crossover coils will have a much lower resistance value than that, but the difference can be compensated by adding the appropriate resistor in series with the coil. Try www.partsexpress.com as a good source for crossover parts. If you have the early crossover, this would be a good time to update. The improved crossover has a 5-ohm, 25-watt resistor and two 220uF non-polar electrolytic capacitors in parallel with the voice coil. Then in series with that network and the audio input is the aforementioned coil. A schematic is shown in later versions of the Model 1/1+1/2+2/3 Owners Manual. (Available as a CD from our webmaster.) Of course, the crossover described above must be built twice, one for each half of the dual voice coil woofer.

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