Realistic 12" Passive Subwoofer 40-4050 Restoration

[mikey3117]

I picked this up over the weekend to add to my Realistic collection and to pair with my modded Minimus 7W's. The veneer was in great shape, just in need of a refinish. The original finish has been sanded. The below pics are after 4 coats of tung oil with at least 1 more to be applied. I even have a clean, perfect replacement logo for the front. The woofer needs refoam and the crossover I'm sure needs a recap. BUT the crossover's caps have really high values, 150uf & 100uf. Am I reading those right? Is this normal for a passive sub to have caps with high values like this? This would make upgraded caps cost prohibitive on this project.

 

[kfa888]

I have that same sub in my office i listen to all the time with some minimus 7's. good match. Here is what the driver looks like if you have not pulled it out...

 

[mikey3117]

I have that same sub in my office i listen to all the time with some minimus 7's. good match. Here is what the driver looks like if you have not pulled it out...

Hey, I'm just down I205 here in Happy Valley. I think I could hear your sub the other night...

I have pulled the driver. I'm about ready to recap the crossover but it looks like I'll have to use electrolytic's for cost purposes...

 

[Copa1934]

I picked this up over the weekend to add to my Realistic collection and to pair with my modded Minimus 7W's. The veneer was in great shape, just in need of a refinish. The original finish has been sanded. The below pics are after 4 coats of tung oil with at least 1 more to be applied. I even have a clean, perfect replacement logo for the front. The woofer needs refoam and the crossover I'm sure needs a recap. BUT the crossover's caps have really high values, 150uf & 100uf. Am I reading those right? Is this normal for a passive sub to have caps with high values like this? This would make upgraded caps cost prohibitive on this project.

Nice cabinet. Looks like a nice speaker.

 

[nexus]

i bought one these for my nephew as a present and he was into high energy rock. he fed it with a 300w tigersaurus amp i also gave to him. it sounded pretty good until he blew it up a year later...

 

[allsmith]

All that walnut veneer looks sooo nice! Nice job! Since im a dummy when it comes to subs, can you explain to me how a passive sub works? Is there no amp in it? Do you just hook up say off of your b speaker output of a two channel receiver? If so how many watts can this sub handle? I think there is one of those for sale close to me on CL, maybe i should check into it, i do love the walnut!

 

[adam-ads]

Those capacitor values sound about right. Low crossover frequencies require big caps and inductors. Electrolytic caps should be cheap.

 

[mikey3117]

Currently waiting on new caps to arrive, and I have a local guy doing the refoam for me. I was going to re-install the "Realistic" logo on the front of the cabinet but whoever at the factory drilled the 2 holes for the logo, didn't use a level...lol I mean, it's not even close to being level!

It's terrible being a perfectionist...

 

[dc270]

For a passive subwoofer it does not get much better than that model. It sounds great with enough power pushing them, like 150 watts! Dayton makes, or used to, a real nice table top sub amp. Putting in fresh caps will go a long way to making this great once again, Erse makes some of the better ones I know of. Good luck with this sub- I bet you are going to love it.
DC

 

[mikey3117]

For a passive subwoofer it does not get much better than that model. It sounds great with enough power pushing them, like 150 watts! Dayton makes, or used to, a real nice table top sub amp. Putting in fresh caps will go a long way to making this great once again, Erse makes some of the better ones I know of. Good luck with this sub- I bet you are going to love it.
DC

Thanks DC... I wish the values weren't so high on the crossover. I just couldn't justify the expense for upgraded caps. Oh well. These should pair well with my modded 7W's or my current restoration project, my Optimus 27's.

 

[dc270]

Thanks DC... I wish the values weren't so high on the crossover. I just couldn't justify the expense for upgraded caps. Oh well. These should pair well with my modded 7W's or my current restoration project, my Optimus 27's.

Some electrolutic caps from Erse should not be that much of an expense, maybe $4~$6 or so! Check them out.
DC

 

[Glen B]

can you explain to me how a passive sub works? Is there no amp in it?

Yes, there is no internal amp (a.k.a. a plate amp). You drive it with an external amp. The amp needs to be driven from a LFE/subwoofer line output of a receiver or preamp, or the amp needs to have some kind of built-in electronic crossover, so that it outputs only low frequencies. There are amps designed for, or that can be used for driving a subwoofer like this one or this one.

Do you just hook up say off of your b speaker output of a two channel receiver?

No.

 

[dc270]

You can take four of these and twist the ends together to get 1200uF
http://www.erseaudio.com/Products/NonPolarElectrolyticAll/ANP10C-05-300-0-PB

$3.30 each!

On some amps you can indeed run your "B" channel for subwoofer use if it is independant/ switchable of the "A" channel and can handle the ohm load to not below 4 ohms total for both channels usually. It varies by amps.
DC

 

[Stuart Pedaso]

Actually, this subwoofer has a passive crossover built in. Just connect your amplifier or receiver speaker outputs to the subwoofer inputs. The internal crossover passes low frequencies to the subwoofer. High frequencies are passed to the subwoofer output terminals where the satellite speakers are connected.

See '92 Radio Shack catalog, page 19.

 

[GD70]

I just bought on of these at my local SA for 13 bucks in near perfect condition.
Hooked t up to my JVC A-X5 amp as described above and it sounds great. The surround is in nice shape.

EDIT: Replacing the surround after all. After a few good workouts, It bit the dust. I ordered a new surround and prepped the driver for when it arrives. Here's a few pics for you.
Glenn

Glenn

 

[allsmith]

Yes, there is no internal amp (a.k.a. a plate amp). You drive it with an external amp. The amp needs to be driven from a LFE/subwoofer line output of a receiver or preamp, or the amp needs to have some kind of built-in electronic crossover, so that it outputs only low frequencies. There are amps designed for, or that can be used for driving a subwoofer like this one or this one.

No.

Thanks ! I sometimes think having a sub would be pretty cool,but i have a vintage 2 channel set up just for music,with ADS L1290 speakers.

I see that i could run my speaker wires into the sub,then out of sub to my 1290's but i just dont like the idea of having anything inline with the 1290's! Not sure if it would hurt anything or not but i just dont like the idea of it for some reason.

So is it better to have a extra amp hooked up to the tape moniter out rca's on my receiver to power the passive sub? (OP sub has a built in crossover right?)

Also could i hook a powered sub up to my tape moniter out if the sub has a built in crossover?

Thanks!

 

[mikey3117]

Ok, so it's been recapped and the woofer refoamed. Unfortunately, the roll on the new surround prevents the stock grill from fitting. Such is life. So, with the refinish, new caps, refoamed woofer...it looks and sounds fantastic!

 

[Donkey Karma]

I just bought on of these at my local SA for 13 bucks in near perfect condition.
Hooked t up to my JVC A-X5 amp as described above and it sounds great. The surround is in nice shape.

EDIT: Replacing the surround after all. After a few good workouts, It bit the dust. I ordered a new surround and prepped the driver for when it arrives. Here's a few pics for you.
Glenn

Glenn

Glen, you still rocking this beast?

One just fell into lap in really nice shape. Considering using in a little vintage 2.1 project I am tinkering with.

 

[scottpro]

I just bought on of these at my local SA for 13 bucks in near perfect condition.
Hooked t up to my JVC A-X5 amp as described above and it sounds great. The surround is in nice shape.

EDIT: Replacing the surround after all. After a few good workouts, It bit the dust. I ordered a new surround and prepped the driver for when it arrives. Here's a few pics for you.
Glenn

Glenn

Glenn, might I ask where you found the correct surround for this? I need to do the same on mine.

 

[GD70]

Glen, you still rocking this beast?

One just fell into lap in really nice shape. Considering using in a little vintage 2.1 project I am tinkering with.

I have it, but out of rotation. My son was using it with the trash find NAD 20's for a while. The bass is outstanding and it's so easy to hook up!