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I need to add balanced output to my single-ended line-level preamplifier. Which trasformers can I look at?
Thank you.
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And have a read here...
And have a read here...http://www.jensen-transformers.com/an/an003.pdf
Agreed. I would opt for "BEST" and use an input trannie at the amplifier instead of an output trannie at the preamp. However I'd recommend using CineMag's CMLI15/15C. They're every bit as good as Jensen's 11P-1 but cost significantly less.
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I recently did this mod to my power amp.For a long time was running a Jensen Isomax Output transformer unit, to convert from unbalanced to balanced, and drive a long run of twisted pair cables to my power amp's electronically balanced inputs.
I recently opened up the amp and added a pair of JT-11Ps, as per Jensen's diagram; still using the unit's original XLR input jacks. Removed the output tranny unit and associated cables on the unbalanced preamp end, just threw on some WBT Nextgens on the twisted pair cables. As per the Jensen literature, I even grounded the shield of the cable (Belden 89207) on the preamp's chassis, instead of combining it with the low wire.
Is this still considered a balanced design? I did it mainly to clean up the number of connections in the chain, and feel I got an improvement in the sound. I now feel most folks who think they need to go “full blown balanced” for long cables, really just need to do this.
Well, the output of your preamp is now unbalanced and the input of your amp is balanced. The cool thing about the input transformers is that they have such a high common-mode input impedance they will provide excellent common-mode noise rejection even when driven from an unbalanced source. And common-mode noise rejection is the whole raison d'etre for going balanced in the first place.If you look at the 11P-1's datasheet, you'll see that while it will give 107dB of common-mode noise rejection from a balanced source, it still gives you 100dB of common-mode noise rejection from an unbalanced source.
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