[LAU] sortof OT -- ART tube pac preamp and compressor noisy?

Ralf Mardorf ralf.mardorf at alice-dsl.net
Tue Aug 13 20:50:45 UTC 2013

On Tue, 2013-08-13 at 12:52 -0700, Rusty Perez wrote:
> But, am I correct, should the card mixer input level then be set to 0
> DB to illiminate the work of another amplifier, and take advantage of
> the work done by the tube pac?

Lower the level of the card's inputs and increase the level of the tube
pre amp outputs (by it's inputs ;) and listen, perhaps it's audible when
the settings don't fit 101% perfect to the optimal operating points of
the card's pre amp and of the tube pre amp. If you can't hear a
difference, than it doesn't matter.

This is the idea:
On Tue, 2013-08-13 at 15:53 +0000, Fons Adriaensen wrote:
> According to the manual, +30 dB. Which is really too much if the
> signal is coming from a preamp which can itself provide +60 dB. 
> What happens is that the preamp produces a very low level hum,
> and you boost that +30 dB. If you set the 1010lt to lower gain
> you can send a stronger signal from the preamp, and the relative
> level of the hum will be lower.

IOW, if you've good luck increasing the level of the tube pre amp will
increase the signal and not, resp. less the hum. Reduce the level of the
card's pre amps as needed.

On Tue, 2013-08-13 at 16:00 -0400, Martin Peach wrote:
> If the motion of the transformer plates is vibrating the elements
> inside the tube, the tube could act like a microphone. In the OP's
> case there is a lot of gain, so it might be the cause.

Unlikely, even a spring reverb shouldn't vibrate caused by vibrations of
a loud, but small transformer. Even a bad transformer still isn't a
truck-mounted seismic vibrator, even not a massage table.

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