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-   -   Power XFMR Choice (http://www.diyaudio.com/forums/tubelab/174032-power-xfmr-choice.html)

sherpa 21st September 2010 03:05 PM

Power XFMR Choice
 
i'm looking at using Edcor's XPWR144 power xfmr for a simple se. my concern is the 3.5A limit on the 6.3 winding, will this be ok or should i try something different? the reason i'm going for the 144 is the 380/320 CT winding will give me options to drop the B+ rail for other tubes.

neonthecat 21st September 2010 04:15 PM

The SSE Assembly Manual states: "The main filament winding should be 6.3 VAC at at least 5 amps."

So, the Edcor XPWR144 may run too hot (or worse) when used at 5 amps.
The folks at Edcor are very helpful. Give the Technical Dept. a call for the definitive answer.



tubelab.com 21st September 2010 04:32 PM

I specify a 5 amp winding to cover all possibilities with some margin. A SSE with KT88's will draw exactly 3.5 amps if all of the tubes are exactly at spec. An EL34 version will draw 3.3 Amps. The filament current could easily be +/- 10% or so. This could put the current close to 4 amps. A 4 amp winding would work, but 3.5 is rather close. See what Edcor says.

Ian444 18th October 2010 10:05 AM

I asked a similar question to Edcor recently, the answer was that their heater windings are designed to handle 10% more current than what they are rated for. So you can pull an extra 10% and after that you're on your own...


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