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4. Re: iRig pre

Subject: 4. Re: iRig pre
From: "Robb Nichols" robb_nichols
Date: Sun Jan 6, 2013 10:09 am ((PST))
All low-cost preamps or DI boxes that I have ever seen just use a simple 
inverting op amp circuit to mirror the the signal of the hot side of the 
balanced signal (Pin 2 or tip of 1/4" balanced connection) onto the cold 
(Pin 3 or ring) to get a balanced output. So the amplifier stage is 
still single-ended.  And in fact some, like a little Mackie 402 mixer 
that I use on my desk, don't even have a signal on the cold side of the 
balanced line.  They are just impedance balanced.  So I don't understand 
how there would be a noise penalty or any loss of signal content by just 
using the hot side of the balanced output to feed an unbalanced input.

On 1/6/2013 9:52 AM, Raimund wrote:
> Taking only one of the two (amplified) balanced output rails could 
> still lead to a degradation of the noise performance. So, I believe 
> that feeding the difference of the two into the unbanlanced input 
> would be better in terms of noise. 







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