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Hammond Transformers


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10/10/2004 8:15 AM
adam
 Hammond Transformers
Hi  
 
I am getting ready to build a small push pull amp and i was wonder what the differances are between the Hammond 125C, 125H, and 125J. Is it just that the H and J are not in the universal line and have an ideal primary impedance or what? Hammonds webpage does not offer much help here.  
 
thanks adam
  
10/10/2004 5:52 PM
bob p
i was looking at those the other day. afict the H and J have fixed values for primaries and leads instead of terminals. in some apps (where the primaries are right) i could see where this would be a lot more convenient. i haven't checked into the prices, but i would expect that the H and J should be less expensive.
  
10/10/2004 11:58 PM
anonymous
That just seems to simple, it sure would be nice if hammond would make real datasheets available for their transformers. The J must have some other differances, it listed as 1 pound, and the H and C are both half ponders. Thats alot of extra weight for a transformer that seems to have the same specs as the J and C. And yes the H and J are about $15 each.  
 
adam
  
10/15/2004 2:49 AM
Brutus
Yes, that is basically the difference.  
 
The "C" is the universal while the 125H has a specific primary of 10K and the 125J has a primary of 2.5K or 4K.  
 
I've had good luck with Hammond universal trannys but feel that I'd go with something optimized for a specific impedance instead. However, if you need 5K instead of 4K then the universal might be the better deal.  
 
Also, I noticed that the universal tranny doesn't have a freq rating (or at least one that I could find). But the specific impedance trannys do, that being 150Hz-15KHz at full power. Interestingly the lowest note on a guitar is 72hz if I remember correctly.  
 
When in doubt, all else being equal and equally unknown, go with the heavier tranny by weight. The response you loose with a light tranny is usually in the bass, and strong bass needs lots of iron.  
 
 
Brutus
  

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