Carlspeak Posted June 2, 2009 Report Share Posted June 2, 2009 I have a 3a marked s/n AR3a41614. The woofer is marked p/n 200003-1. I measured Re of 2.67 ohms, Le of .742 mH.The mystery is the coil in series with it. It is clearly marked #8. I measured the inductance at 120 hz and got about 3.0 mH which agrees with the #8 coil spec.Anybody familiar with 3a's enough to help with this? Should I leave 'well enough' alone? or, replace with a #9?Help! Link to comment Share on other sites More sharing options...
genek Posted June 2, 2009 Report Share Posted June 2, 2009 Should I leave 'well enough' alone? or, replace with a #9?If I had your equipment and supply of spare parts, I probably wouldn't be able to resist trying it both ways and doing some comparative measurements. Link to comment Share on other sites More sharing options...
Carlspeak Posted June 2, 2009 Author Report Share Posted June 2, 2009 If I had your equipment and supply of spare parts, I probably wouldn't be able to resist trying it both ways and doing some comparative measurements. Sounds intreaguing but I have to have this one restored and out the door by next Monday. The original owner's other 3a has an older round ceramic woofer with a #9 inductor. No serial number on this one. Link to comment Share on other sites More sharing options...
speaker dave Posted June 3, 2009 Report Share Posted June 3, 2009 Sounds intreaguing but I have to have this one restored and out the door by next Monday. The original owner's other 3a has an older round ceramic woofer with a #9 inductor. No serial number on this one.Since a #9 is 2.85 mH I would be very tempted to leave well enough alone. The 5% increase is inconsequential.Can't even guess why it would be a different value, but it sounds like a factory running change?David Link to comment Share on other sites More sharing options...
johnieo Posted June 16, 2009 Report Share Posted June 16, 2009 I have a 3a marked s/n AR3a41614. The woofer is marked p/n 200003-1. I measured Re of 2.67 ohms, Le of .742 mH.The mystery is the coil in series with it. It is clearly marked #8. I measured the inductance at 120 hz and got about 3.0 mH which agrees with the #8 coil spec.Anybody familiar with 3a's enough to help with this? Should I leave 'well enough' alone? or, replace with a #9?Help!Hi Carl:Sounds like the line ran out of #9 and grabbed the closest value until more arrived. I sure wouldn't change it. Roy C has measured several coils clearly marked with #9 and found them to vary from 2.7 to as high as 3.2 mH. everything after s.n. about 38,500 should have been #9 to go with foam-surround woofer.Cheers, Link to comment Share on other sites More sharing options...
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