I purchased a pair of plate subwoofer amps from Parts Express for about $125 each (part of a DIY subwoofer kit). I think the version I bought have about 200 wpc. The plate amps, of course, have a variable low pass filter, phase and level controls. I believe the cross-over is 24 db/octave. I ran the specs of these amps by JD at Gallo. He checked with Anthony and said they should work fine. They certainly seem to, though I haven't compared them to other amps. I'm sure they don't have the authority of a higher quality amp, but this was a pretty inexpensive solution to get a true dual mono power source for the second voice coils.
Rich et al:
- I maintain that the amplifier you purchased from Parts Express is essentially the same one used in each channel of the Gallo SA. Read the specs on this particular model at the below link and see if you don't agree:
DAYTON SA240 240W SUBWOOFER AMPLIFIER
Part Number 300-804
This mono amplifier is rated at 240 watts rms into 4 ohms at 0.1% THD. This spec is identical to the spec for the Gallo SA - see the user's manual for the Gallo SA at their website. Note that the Gallo Sa is rated into 4 ohms, not 8, as is this particular PA. Many other specs of the units are identical. Too big of a coincidence.
One key difference (other than the fact that there are two identical 240w channels in the Gallo SA) is that the Gallo product adds the EQ control, which allows tailoring the boost at about 26 Hz by -3 dB to +6 dB. In my opinion, this is a key feature that really makes the Gallo product much more useful than a PA without this feature. Note that this is different than simply turning up the gain on the SA channel, which boosts all frequencies in the passband by an equal amount. The EQ control, as can be seen by the frequency response curves in the Gallo SA users manual, varies the Q of the circuit providing a localized boost in the mid 20 Hz region, just where it's most needed.
Of course, anyone with a knack for designing and building simple filters could put together a smiliar control to be used with the Dayton product, or perhaps there's one that can be bought off the shelf. In any event, given the price of the Dayton PA, one could purchase two of them for $240 plus shipping, which is ALOT less than retail of the Gallo unit.
I would also suggest that the use of the Hsu amp described above, while it may improve the bass performance of the system, would not be expected to provide the performance of the Gallo SA without anything equivalent to the Gallo amp's EQ control.