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5e3 power transformer specs


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9/20/2002 12:59 AM
Facundito 5e3 power transformer specs
Im building a 5e3 clone. My question is:  
 
Wich are the power transformer specs?  
 
Thanks in advance!  
 
Facundo
 
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9/20/2002 3:37 PM
Bruce/ Mission Amps

Using a NOS 5Y3GT rectifier, any PT that will give you about 375vdc@110ma under idle condition loads with two 6V6s, a 12AX7 and a 12AY7 will work fine.  
Bruce
 
11/9/2002 6:22 PM
Henrik

That sounds simple enough, but exactly what trannie secondary voltage does it amount to? 300-0-300? Excuse my ignorance, I'm a newbie...  
 
T.I.A!
 
11/10/2002 8:07 PM
Bruce /Mission Amps

The secondary voltage can be nearly meaningless without knowing how the PT will react under load Henrik.  
I've found that a Hammond 272DX, 300v@125ma power tranny, will typically deliver over 460vdc unloaded, and even +400vdc under a medium load with a good rectifier. It will work for your porject with a little tweaking.  
I find the Hamnmond PTs always run at least 106% to 110% over their stated AC secondary voltage, even when loaded down.  
The trannies are a bit stiff and wound with 115vac primary input in mind.  
The 120v Fender Deluxe tranny I've been using in the 5E3 kit is rated at 340vac@120ma but is a little soft when run in this amp at 5E3 idle current levels, so it works out just a bit high with a NOS 5Y3GT rectifier tube and better with a 12v-15v zener diode in the secondary center tap.  
 
Bruce
 

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