Collins Transformer Page

                                For Roz762




The transformer seems to have two windings, I did not check them with a ohm meter but there are three terminals on one side which is probably a center tapped primary. The other side has four terminals, which I will guess is a secondary with taps for impedance matching. The core stack is 2 ¾” thick 8 ¼” across the top and 6 7/8” high. The name plate is hard to read but it states a range of 100 to 5000 cps. With this much iron available it should make a real bear shit amplifier. Because this is a commercial unit I expect the ratings to be rather conservative. It wouldn’t surprise me if you could squeeze 300 watts through it. The trans weights around 58 pounds, by the time it is packaged for shipment by UPS it would be close to 60 pounds. It would be shipped from Fort Benton, Montana 59442, so you should consider shipment costs. I have no idea what the lamination thickness or alloy is.

The pictures below are in a thumbnail format, click on them to see a larger version.   



Some more thoughts on this transformer. The audio input to this transformer was usually PP class B which would balance the DC current in the primary. The secondary however would supply all of the current to the transmitter through a single ended winding, putting a large DC bias on the core and looking somewhat like a SE amp. I got to thinking that there must be a gap somewhere so I took another look at the transformer. I found the gap and it is quite obvious if you look for it, It is partially filled with paint and I missed it because I was not looking for it. It looks as if the core is composed of two E sections butted end to end with the gap between the two. Look at the third picture, below the middle terminal and the gap is visible. I get a glint in my eye thinking about what a great100/200watt SE amp this would make with 10 to 20 807s or 1625s glowing on top of the chassis. I get over it in a hurry when I remember how I hate to wind transformers and also the probability of getting a hernia when moving it. With a core this big, this trans could probably be wound with house wire. 10 1625s to 8 ohms would only require a turns ratio of about 9 to1.



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