Arny Krueger wrote:

"MD" wrote in message



I use the unit on tape out of my int amp


The signal levels on a tape output are in the 0.100 mV to 1
volt range.

The DSP 1124 being designed for pro audio, its designed for
signals in the 1.3 to 6-8 volt range.


I have huge room bumps at 48hz, 68hz and 130hz- the unit
works great to fix these with no negative side effects -
especially in the highs - chan separation -



EXCEPT - it
adds white noise on its output (I can tell it's the
output because I can disengage the filters and the noise
is there - as well as try to use the filters to find the
noise - which I cannot. It is barely noticeable with a CD
input - but there - and very obvious when I use phono
(lower level input).


You've nailed the problem - the signal at the tape outputs
is too low to optimise the noise performance of the DSP 1124


The specs say noise is less than -94db. This doesn't
make sense


Those specs are probably referenced to +4 vu, which is about
1.25 volts. The signal coming out of your phono preamp could
be 10 times, or 20 dB lower.


Is this because I am running single ended?


Not really, though driving the DSP1124 effectively makes it
6 dB more sensitive.


Is there a way to bump up the input level of the device
to increase the sig/noise ratio?


Boost the output of your inputs especially the phono preamp,
or as Stephen sugegsts, move the equalizer to a point in the
signal chain where the signals are larger.


thanks - no pre out- I'm stuck I guess
shame - cause the unit does wonders on the bumps (I use a multitude of
test discs - including one with one hz steps from 20-300hz - and a sound
meter)