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<blockquote data-quote="frank kayser" data-source="post: 23366" data-attributes="member: 28">Re: Line level IsolationGreat timing - I got bit by hum last week, with nothing on-hand.&nbsp; One acoustic guitar with amp plugged in via output XLR. Same guitar would hum in a different amp that was clean with a second guitar.&nbsp; If the guitarist touched the 1/4 out, problem went away.&nbsp;&nbsp; 1/4 swapped - still noise.&nbsp; Plugging guitar into DI and then into LowZ in the amp actually made it worse (ground lifted or not...) Disconnecting from the board solved the problem.&nbsp; Since it was localized to his guitar, I suggested a trip to the luthier.&nbsp; He had some problems before (not always) but the luthier could not find anything.&nbsp; Ah, but that is another issue.&nbsp; Isolation between the board and amp would have solved it.I was looking at the WW ISO1, ISO2,and the inline ISOXL.&nbsp; I do like the Radial products - the question is why not to use the Whirlwind.I got this note back from Whirlwind comparing their products:Hello from Whirlwind,&nbsp;&nbsp;The ISOXL does have a smaller transformer and its frequency response will not be as low as the larger TRSP600L used in the larger box type ISOs. The frequency response spec at 100 Hz, 0 dBu is -0.13 dBu. That&#039;s not bad as long as you don&#039;t drive it really hard.&nbsp;The spec on the TRSP600L @&nbsp; is 20 - 20k Hz, +/- 0.57 dBu but at +20 dBu.&nbsp;So the ISOXL becomes a handy and relatively inexpensive problem solver. In fact, they&#039;re used all the time to isolate mixers from amplifiers in PA systems.&nbsp;The ISO1 uses the same TRSP600L transformer as the Line Balancer but only has the single channel of isolation without the splitting capability but it&#039;s a bit less expensive.I guess my other my other question is when do these different specs become audible?frank</blockquote>

[QUOTE="frank kayser, post: 23366, member: 28"] Re: Line level Isolation Great timing - I got bit by hum last week, with nothing on-hand. One acoustic guitar with amp plugged in via output XLR. Same guitar would hum in a different amp that was clean with a second guitar. If the guitarist touched the 1/4 out, problem went away. 1/4 swapped - still noise. Plugging guitar into DI and then into LowZ in the amp actually made it worse (ground lifted or not...) Disconnecting from the board solved the problem. Since it was localized to his guitar, I suggested a trip to the luthier. He had some problems before (not always) but the luthier could not find anything. Ah, but that is another issue. Isolation between the board and amp would have solved it. I was looking at the WW ISO1, ISO2,and the inline ISOXL. I do like the Radial products - the question is why not to use the Whirlwind. I got this note back from Whirlwind comparing their products: [I]Hello from Whirlwind, The ISOXL does have a smaller transformer and its frequency response will not be as low as the larger TRSP600L used in the larger box type ISOs. The frequency response spec at 100 Hz, 0 dBu is -0.13 dBu. That's not bad as long as you don't drive it really hard. The spec on the TRSP600L @ is 20 - 20k Hz, +/- 0.57 dBu but at +20 dBu. So the ISOXL becomes a handy and relatively inexpensive problem solver. In fact, they're used all the time to isolate mixers from amplifiers in PA systems. The ISO1 uses the same TRSP600L transformer as the Line Balancer but only has the single channel of isolation without the splitting capability but it's a bit less expensive.[/I] I guess my other my other question is when do these different specs become audible? frank [/QUOTE]

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