Bridged mono for sub amp?  

I built a box for my 12 in. Dayton 1200 Titanic subwoofer. It is powered by my old but capable Adcom GFA 545II. It does a great job but the subwoofer can handle a lot more power than this amp can deliver. The 12 in. Titanic has a nominal impedance of 4 ohms. The Adcom can pump out about 200 watts into 4 ohms, but the sub can handle 500 watts. I learned one way of getting more power from an amp is to bridge the output by connecting both channels to output as one channel mono or bridged mono as it is called. My manual says nothing about how to do this.
How does one setup an amp for bridge mono? A link to a diagram showing how the
two channels should connected would be a great help too. Thanks for any advice, suggestions, and tips.

Thanks Wayne and whoaru99 for your replies. I decided not to hook it up bridged mono. I agree with Wayne that it could be risky since the amp does not have a bridged mono switch on it (probably for a reason). That reason might have been hit upon by whoaru99 in his reply that this amp is probably not designed for this task sinceit would be like driving a 2 ohm stereo load with the 4 ohm speaker connected to bridge mono. Until I can find a good high end subwoofer power amp, I will continue running my Adcom from one channel. 200 watts rms into 4 ohms will be ok for most movies, except perhaps War of the Wars with it's very demanding LFE. If anyone has a suggestion for one, please let me know. It must be a separate amp not designed to be mounted on the subwoofer. Those I have seen have smallish transformers and power supply filter caps ranging 10K to 15K uF, yuck. If money were no option I would go for the Gallo sub amp but it is expensive. Pro power amps
are another option but I don't want to mess around with balanced line inputs coming from
my unbalanced subwoofer line out (I have the Pioneer VSX-1015TX). Anyway, thanks again for your help and I am open to other options in sub amps.

Star Hawk

The subwoofer enclosure is 3.2 cu ft and sealed. I did not measure the f3 due to lack of equipment, but according to the specs and plans for the enclosure for this small internal volume, partially filled with fiberfil stuffing, it should be ~25 HZ. The 545 is a good amp and even drives a 4 ohm nominal Z driver like the 12" Titanic without clipping. But I have not tested it yet with the recent War of the Worlds release. If I do view the movie I will probably use my Pio amp -10 db subwoofer out attenuator just to be on the safe side.

Thanks for the suggestion. Others have mentioned the QSCs too. Sounds like it will be worth taking a look at them.

What interconnects did you use to go from your HT receiver (or discrete HT preamp) to your QSC 1450. The specs I just reviewed only listed balanced line inputs:
"Barrier strip, XLR and 1/4" balanced inputs plus Speakon and binding post outputs provide easy connections." Unless your HT receiver has a balanced subwoofer line out, did you make or buy special interconnects? What about impedance matching?
I wanted to avoid this, unless there is an easy way around it.

It sounds simple enough. Another question for you. Would it be better to buy a balanced line cable and cut off the XLR connector at one end and solder an RCA plug hot lead to the corresponding pin 2 wire and the shield to the corresponding pin 1 wire? Or take a length of unbalance cable, cut off the RCA plug at one end and solder an XLR connector (male, right?) pin 2 to the hot lead and the pin 1 to the shield. Does it make any difference which way?

Great! Now I need to decide which QSC to buy. Thanks.

I am definitely going to order a QSC. I was looking at the RMX1450 but for $100
less I can still get all the power I'll need from the model you have, the RMX850. And I am back full circle 'cause I bought my 12" Titanic at Parts Express. I was not impressed by their subwoofer amps and so I had the idea of trying my old Adcom 545 amp which works ok but may wimp out on real powerful deep bass LFE. So all the time the amp I really need is right under my nose. I will check out PE's pro cables at the same time to see if they have something like yours. Thanks for your very helpful suggestions. :cool: