add plate amp to unpowered sub?

Jim Shearer

I have an old unpowered 10" sub w/ my little Visonik David 602 speakers that I would like to modify so I can use it in a future project. It's a really solid sub in a nice cabinet that my wife looks favorably upon. (Critical factor!)

I openned the box & checked the driver to be sure the surround is still good, which it is. Then I checked the driver to see about impedence, etc. When I bought the sub they said it used a dual voice coil so that you could have a single driver for both channels. Turns out that it is a single voice coil and the stereo signals are summed by a TRANSFORMER which feeds the driver! No indication of the driver's impedence and I have no test equipment beyond a VOM.

SO, is it likely that I can remove the cross-over and transformer, enlarge the openning in the back of the case, and add a plate amp from PartExpress? This seems reasonable to me, but then I don't know much about designing speakers.

Thanks, Jim

disneyjoe7

Huh, if it has a transformer I like it has an amp also.

Q, does it have an RCA input for the sub? If so it as an amp now.

Jim Shearer

disneyjoe7 wrote:

Huh, if it has a transformer I like it has an amp also.

Q, does it have an RCA input for the sub? If so it as an amp now.

As stated, the transformer is used to sum the L + R signals and pass them to the driver. No amp. Only input is the L & R speaker wires, output is L & R speaker wires to the Visonik David 602's. If there was an amp inside the sub, then I wouldn't need to do anything.

Cheers, Jim

disneyjoe7

Ok, don't see why you can't add a plate amp.

ohskigod

look at the bracing, if there is any. if you can see inside of it (I assume by popping out the driver, make sure there is room to mount the plate amp. another option is to remove the terminals/transformer thingamabob, seel the hole with a piece of mdf with just one speaker terminal (which you would wire directly to the driver)

you can then get a plate amp (since it is one channel and has a built in crossover) and mount it in a seperate box.

factoring in if you have the room (without cutting bracing) to mount the amp directly to the cabinet, do whichever is easier.

Systems

The thing that looks like a transformer is probably a large inductor to remove hi frequencys.It and any capacitors or other crossover parts should be removed if you add the plate amp.

Jim Shearer

GV#27 wrote:

The thing that looks like a transformer is probably a large inductor to remove hi frequencys.It and any capacitors or other crossover parts should be removed if you add the plate amp.

I hadn't thought much about that, but it seems likely. In any event, the transformer-like device takes in the L and R signals separately and outputs mono to the driver. It just threw me for a loop when I saw it. :eek:

Thanks guys, I feel a bit more confident in ripping out the cross-over and "summing" device and installing a plate amp. Then I can use it w/ any speakers I like. (he says as he carefully advances his dark plans.)

Cheers, Jim