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Matching Output Xformer to Spkr
#1

I've never seen this addressed before but when calculating the voice coil impedance in order to find a matching output xformer, don't you need to also include the hum bucker coil impedance in series with the voice coil? I recently dismantled a speaker and the hum bucker was separate on the pole piece. It had a decent amount of wire in that coil, surely enough to affect the overall impedance! Thanks

Ron

Bendix 0626.      RCA 8BX5.   RCA T64
Philco 41-250.    Philco49-500
GE 201.             Philco 39-25
Motorola 61X13. Philco 46-42        Crosley 52TQ
Philco 37-116.    Philco 70
AK 35                Philco 46-350
Philco 620B.       Zenith Transoceanic B-600
Philco 60B.         Majestic 50
Philco 52-944.    AK 84
#2

Well...yes you do. However I think compared to the voice coil the humbucker which is a much thicker wire coil shouldn't amount to too large a percentage. In addition the voice coil impedance is larger than its mere DC resistance as there will be the inductive component.
Plus when you replace the transformer it will likely be a good enough match, not an exact one.

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
#3

Thanks Mike. I've seen some speakers listed with impedances of an ohm or two. The hum bucker coil I saw had a fair amount of windings so I'm thinking it would account for a fair amount of the total including voice coil.

Ron

Bendix 0626.      RCA 8BX5.   RCA T64
Philco 41-250.    Philco49-500
GE 201.             Philco 39-25
Motorola 61X13. Philco 46-42        Crosley 52TQ
Philco 37-116.    Philco 70
AK 35                Philco 46-350
Philco 620B.       Zenith Transoceanic B-600
Philco 60B.         Majestic 50
Philco 52-944.    AK 84
#4

Better yet, early Philco speakers are fractions of Ohm.

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.




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