PASSIVE SUBWOOFER DRIVEN by a 2 CHANNEL PRE-AMP + MONOBLOCK ?


I’m hoping someone can advise me so a sub question
I have an 18 inch Passive subwoofer , the Wilson Benesch Torus

for some reason the engineers sell it with an external amp/crossover module . Inside is a 200 watt class Ab amp. To add insult to injury, I noted some made in China capacitors . A disgrace at this price point LOL

ive never been game to run it loud because I don’t think the amplifier has enough juice

if I experimented , say , using a stereo preamplifier and a 600 watt bryston monoblock and run my XLR cable from the subwoofer out on my home theatre processor —-> to my all analog stereo pre amplifier then only 1 channel on the preamp is being used . Of course the preamp then connect to my Bryston monoblock via an XLR plug



am I potentially doing damage to my preamp by only using one of its channels ?

200 watts seems a tall order to move an 18 inch cone at 20 hz at 80 decibels . I’ve spoken to several techs who feel most of the made in China subwoofer plate amplifiers are rubbish so I’m trying to avoid class D Chinese amps.

the Torus is a good  sub for 2 channel duties I remember reading it’s not that good for home theatre. Thank you if anyone has input.
wt4158
for some reason the engineers sell it with an external amp/crossover module .


Lots of good reasons to do this, including not subjecting the electronics to the rumblings of the inside of the cabinet, and vice-versa.


Inside is a 200 watt class Ab amp.

Which is actually pretty fancy, considering even high-end subwoofers come with Class D most of the time.

To add insult to injury, I noted some made in China capacitors . A disgrace at this price point LOL

The very worst examples of an armchair speaker/electronic buyer are those who throw aspersions without any knowledge at all about what they are talking about. The quality of parts coming from China ranges from the exceptional to poor, like parts in any other place. In fact for many types and ranges you'd be very hard pressed to find a better country of origin than China.

I have not heard this subwoofer, but I think the idea of making an amp specifically with speaker level inputs in mind is quite clever.  I suggest to the OP that his snobbery will lead him only to spending money on peculiar pieces of kit instead of enjoying great audio gear.
I find it hard to believe the OEM would sell an amp that is undersized.   You don't know until you listen.  And yes, many parts are made in China. 
I agree with your approach.  I had a plate amplifier die and then bypassed it and ran directly into the woofer from a amp connected to the sub out.

Worked fine. 

Keep experimenting until you are either out of ideas or out of money. 😁

I eventually built a 15 inch with dual passive radiators driven by a McIntosh amp in bridged mode. 

A non vented box gives a smoother frequency curve but not as strong a bass. A tradeoff. Certainly requires more power which is why almost all active subwoofers are vented. 

Vented boxes will have a peak resonance. This can be tuned by changing the length of the port insert tube. 

Experiment and have fun.