peavey actually has a decent bit. you may be familiar with the issues, so consider this a "for posterity" post. :-)
the manual indicates the input sensitivity is selectable, but it appears to be software based. that might be a weak point.
input sensitivity is +24dbu, which is about 12 volts, so that may be what is required to maximize s/n on the input.
any less than that may cause a reduction in s/n. it is unclear if the input software attenuator reduces s/n in -10dbv mode. my guess is since it is done in software, s/n would be lost. so coming in with a 2v signal, for example, would lose about 13db s/n or so right off the bat.
output is also +24dbu, so that may be what is required to maximize s/n on the output.
any less than that may cause a reduction in s/n.
those are VERY hot signals relative to what most folks are use to working with. some consumer amps without gain controls may have input sensitivity of 1v, so that means coming in 12x too hot, which means the signal would have to be reduced by about 23db or so (which if done digitally kills 23db of s/n). whereas an amp with a lower gain (higher input sensitivity) and an analog attenuator could run with the hot signal and preserve the s/n ratio (not lose the 23db).
so with just two mis-steps, s/n could drop 36db or more. next thing 105db becomes 69db and on a horn with 109db 1w1m sensitivity, that could be 60db of noise coming out of the horn by inserting the device even though nothing is wrong with the device!