I was studying the MC275 schematic and was wondering what the turns ratio is for that output transformer.
I searched and found another thread where Douglas (Bandersnatch) said that it is 8:1 to the 8 ohm tap. I'm guessing that this is the ratio of turns on one of the primaries to the 8 ohm secondary (three total primaries). Since the output tubes work into two of the primaries, as far as the output tubes are concerned the turns ratio is 16:1.
Is this correct? Anyone know anything about these transformer specs?
I searched and found another thread where Douglas (Bandersnatch) said that it is 8:1 to the 8 ohm tap. I'm guessing that this is the ratio of turns on one of the primaries to the 8 ohm secondary (three total primaries). Since the output tubes work into two of the primaries, as far as the output tubes are concerned the turns ratio is 16:1.
Is this correct? Anyone know anything about these transformer specs?
Thanks, Daniel.
I was looking at the Plitron unity coupled transformer and the turns ratio seemed a bit high (over 28:1 ratio for all primaries to the secondary). If the Mac transformer is exactly 600 ohms this would be a turns ratio of about 8.6:1 per primary winding or a little over 17:1 for the entire output tube load, since it uses two windings to load the power tubes.
Have I got all this right?
It seems that the primary impedance of the Plitron is quite a bit higher at about 1600 ohms for the plate to plate winding with an 8 ohm load. It seems to me at first glance that you wouldn't get nearly as much power out with the Plitron transformer.
Any thoughts?
I was looking at the Plitron unity coupled transformer and the turns ratio seemed a bit high (over 28:1 ratio for all primaries to the secondary). If the Mac transformer is exactly 600 ohms this would be a turns ratio of about 8.6:1 per primary winding or a little over 17:1 for the entire output tube load, since it uses two windings to load the power tubes.
Have I got all this right?
It seems that the primary impedance of the Plitron is quite a bit higher at about 1600 ohms for the plate to plate winding with an 8 ohm load. It seems to me at first glance that you wouldn't get nearly as much power out with the Plitron transformer.
Any thoughts?
Download a copy of the Radiotron Designer's Handbook. It covers the McIntosh output transformer design.
If you split a standard output transformer between the plate and cathode, you've changed the turns ratio by splitting the primary that way (4 not 2 sections). If you work the turns vs. impedance equation then, it all makes very simple sense!
_-_-bear
If you split a standard output transformer between the plate and cathode, you've changed the turns ratio by splitting the primary that way (4 not 2 sections). If you work the turns vs. impedance equation then, it all makes very simple sense!
_-_-bear
As far as I can tell, Plitron is spec'ing that high 28:1 ratio for a 4k primary impedance, which is the equivalent load seen by the tubes, given a 5 ohm secondary impedance. The actual windings are 1k, like the MC30, but for a strange 5 ohm secondary. I'd hope that they could make a standard 4/8 ohm winding instead. Nice transformer, but the price is way out of my league. 
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