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previous: Man o'Blues Your heater winding rated @5A is ov... -- 11/19/2003 3:15 PM view thread

Re: Filament rating

11/19/2003 5:22 PM
Major PainRe: Filament rating
Thanks for the great info fellas.  
 
This was the first time Ive had to deal with filament overvoltage before. I just really never used the hammond PTs but a couple of times and in the last build I used 6550s as power tubes so that brought down the filamnet voltage in that build.  
 
I did try the EL34s in the amp and it did bring the filaments down to 6.9vac but the circuit gained some slight extra 60hz buzz into the background for some odd reason so I went back to 5881s for a good smooth clean sound.  
The hammond trannies are really excellent trannies but they really need to change the primaries up to at least 120vac.  
maybe I'll email them about this and see what they say the reason to stay at 115vac is for.  
 
I'll do the resistor drop to get the filaments to a more decent voltage.  
 
I do wonder how filament voltage within a preamp tube effects the tubes operating character and tone in the preamp.  
 
M.P.