some of you might remember my mixer project here: http://www.groupdiy.com/index.php?topic=42359.0
I've built a few units, and I have a wierd problem that I can't explain. some values have been adjusted since then, but the input and output impedances are still the same.
using my NTI MR1 signal generator and ML1 analyzer plugged into the link input and the output passing a -12db signal it comes out at -12db - all good..
BUT if I put two units in series, so MR1 into link1, then out1 into link2 then out2 into ML1 it comes out at -6db ???
so somehow 0db gain + 0db gain = 6db?
I can't think of any explanation except an impedance mismatch of some sort..
a balancing issue could obviously cause 6db, but it doesn't matter which order I put the two units in, and the mic/aux inputs on the first one in the chain also come out 6db hotter than the second unit
I figure since it's a perfect 6db there has to be something that I'm missing here.
any ideas?
Jason
I've built a few units, and I have a wierd problem that I can't explain. some values have been adjusted since then, but the input and output impedances are still the same.
using my NTI MR1 signal generator and ML1 analyzer plugged into the link input and the output passing a -12db signal it comes out at -12db - all good..
BUT if I put two units in series, so MR1 into link1, then out1 into link2 then out2 into ML1 it comes out at -6db ???
so somehow 0db gain + 0db gain = 6db?
I can't think of any explanation except an impedance mismatch of some sort..
a balancing issue could obviously cause 6db, but it doesn't matter which order I put the two units in, and the mic/aux inputs on the first one in the chain also come out 6db hotter than the second unit
I figure since it's a perfect 6db there has to be something that I'm missing here.
any ideas?
Jason