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ESS AMT 1 impedance controversy...
ESS AMT 1 impedance controversy...
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Old 18th February 2005, 12:24 AM   #1
Urloony is offline Urloony  United States
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Default ESS AMT 1 impedance controversy...

I have read here among the threads that the measured impedance of the AMT 1 series the "great heil" is about 4 ohms. However, I keep hearing about some AMT 1's that are 8 ohms. I have a pair of AMT 1's and the measured DC resistance is about 6 ohms. Is it possible to have a 4 ohm AMT with a measured DC resistance higher than it's impedance or do I in all likely hood have 8 ohm AMT's? I've included the original graph I found posted here. To add to the confusion I called Orange county speaker repair , who sell replacement ESS AMT diaphragms and asked them the impedance of the diaphragm. The sales rep said they were 8 ohm as listed in their computer. When I asked her if she could double check she spoke with a tech who said they are actually 4.
So what gives? There's also this ebay item that claims his AMT 1 is 8 ohms.
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Old 18th February 2005, 10:37 AM   #2
Gregm is offline Gregm  Europe
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I've included the original graph I found posted here
Is there no way you can measure your amt1s? The impedance will be frequency dependant anyway and you want to know what it is at the chosen x-over frequency. The nominal value is an indication only...

The graph you attached shows impedance varying b/ween ~3,2-3,7 depending upon frequency, anyway, not 4ohm.
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Old 23rd February 2005, 03:56 PM   #3
JohnL is offline JohnL  United States
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Ahh... that explains the blip at 1200 that I can't seem to get rid of. I thought the fs was around 800. In any event, my Great Heils (from an AMT 1B - old diaphrams) measure 3.9 Ohms with a meter.

BTW, have any of you played with the Eton ER4s. I just got a pair and can't wait to try them in something.

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