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Playing with Allied ITs

Yesterday I received my pair of interstage transformers from Allied. These are the $13 part # 6W68HF. Dan Marshall has posted a lot of information on JoeNet about using them with a bridging cap to kill ringing and extend the high end. Well, last night I connected them to a scope and function generator. Putting a 5 kHz square wave in showed a good deal of ringing. Connecting a 0.1 cap between the pri and sec killed the ringing dead. There was a bit of rounding to the leading edge, but nothing at all serious.

I ran some quick curves by estimating the amplitude of the scope traces and was not happy. This morn I got out my pair of redoubtable EICO #221 VTVMs and allowed them to warm for a couple of hours. Better results and I think more accurate.

At 20 Hz, down 0.2 dB
at 27, -0.1
33, 0
staying there until 60K, where it was down just the smallest that I could read, say 0.05 dB

Strangely, it was the same with 560R or 2.2K source Z.

I believe these little devils will work! Unbelievable for $13. They are going in my type 46 amps, configured thusly: PT-157 Nickel Wonder input tranny > 5687> IT> 46> IT> parafed ultrapath 46 output. I'd put a DHT on the input if I could find one with u of 10 or greater and an Rp that these ITs could deal with :-)

Next, I'll try them in a live circuit.

Cheers/Don


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Topic - Playing with Allied ITs - Don Carron 06:40:57 09/5/01 (11)


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