Hello, I'm new here and I'm looking for someone with experience or advice on restoring a nice pair of Allison 3 speakers. Here's the backstory.
I picked up a pair of these from a nice older guy who had them from new sometime in the 80s. I got them cheap, and they're in very good condition which means I'm lucky. I've enjoyed them a lot since I got them almost a year ago. Recently I noticed that the sound seemed unbalanced, and it looks to me like the mid-range driver (3.5" "fried egg") on one of the units is not producing sound. I haven't gotten the multimeter out or checked the crossover yet, but I presume the voice coil on that driver has died.
Based on my brief research into these speakers, I've learned that these are considered by many to be a very good near-audiophile grade of speaker, but they are also relatively rare, very unique and not easy to repair.
Does anyone have advice to share about troubleshooting and possibly replacing the mid-range driver on my speaker?
Thanks a bunch!
I picked up a pair of these from a nice older guy who had them from new sometime in the 80s. I got them cheap, and they're in very good condition which means I'm lucky. I've enjoyed them a lot since I got them almost a year ago. Recently I noticed that the sound seemed unbalanced, and it looks to me like the mid-range driver (3.5" "fried egg") on one of the units is not producing sound. I haven't gotten the multimeter out or checked the crossover yet, but I presume the voice coil on that driver has died.
Based on my brief research into these speakers, I've learned that these are considered by many to be a very good near-audiophile grade of speaker, but they are also relatively rare, very unique and not easy to repair.
Does anyone have advice to share about troubleshooting and possibly replacing the mid-range driver on my speaker?
Thanks a bunch!
look at this page and check the midrange switch and caps
Allison Three crossovers - Allison - The Classic Speaker Pages Discussion Forums
Allison Three crossovers - Allison - The Classic Speaker Pages Discussion Forums
Thanks for the troubleshooting advice.
I have seen some posts that indicate that the driver needs to be removed from the crossover before continuity testing, but I'm not sure if you're comments about "inboard / bare wire" mean that it's not necessary for a basic continuity test.
I have seen some posts that indicate that the driver needs to be removed from the crossover before continuity testing, but I'm not sure if you're comments about "inboard / bare wire" mean that it's not necessary for a basic continuity test.
Disconnect the wires at the mid's input terminals then measure its DC resistance with your multimeter.
No reading (infinite resistance) means an open circuit, either in the voice coil itself or in the wires connecting the input terminals to the voice coil (the inboard wires?).
If the voice coil circuit is intact i.e. continuous, then expect a reading of several ohms.
No reading (infinite resistance) means an open circuit, either in the voice coil itself or in the wires connecting the input terminals to the voice coil (the inboard wires?).
If the voice coil circuit is intact i.e. continuous, then expect a reading of several ohms.
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P.S. I agree that the mid's level adjusting switch may be the problem.
Try operating it many times in the hope that will clean the switch contacts and restore the operation of the mid.
Try operating it many times in the hope that will clean the switch contacts and restore the operation of the mid.