Passive Sub Amplifier

[lbjazz]

After reading several threads on this forum I am now thouroughly boggled on what will be the BEST way to set up my system.

I am about to come into a set of Southeast Acousitcs speakers. (You probably have never heard of them. The company was based out of flordia and did a lot of stuff for Disney and Universal but has since shut down) I haven't heard them yet, but my dad has and he says they sound great (especially considering that we're going to get 10 speakers and 2 subs for about $100 - some people just don't know what they have) We'll each get a full 5.1 setup. I plan on buying a Denon 3805 reciever for the system. (yes I know the remote sucks, but I like Denon sound and I don't need the features of the 3806 nor will I any time soon) The problem is that the subs are passive. I know that I could run a cable from the sub-out on the reciever to something like an outlaw monoblock and then run speaker wire to the sub. However, that will add another $300 that I don't really have. Can I use the amps in the Denon to drive my sub without sacrificing something? Also, if I go with an outboard amp, what other brands are good options in the $0-$300 range?

One more problem . . . None of those 10 speakers are specifically meant to be a center channel. Is this going to be a problem (other than making it fit where I need it to?)

 

[jaxvon]

Assuming that you're getting a high-quality subwoofer with some good power handling, I think you'd do very well with a high-power pro amp.

This is a good amp, but if you run it bridged, it will only drive an 8-ohm speaker. I think most subs tend to be 4 ohms:

http://www.musiciansfriend.com/srs7/g=live/search/detail/base_pid/480780/

This is another good amp, but it has a fan (which might be annoying unless you can put the amp somewhere else):

http://www.musiciansfriend.com/srs7/g=live/search/detail/base_pid/480696/

 

[droeses58]

A mono block amp IMO is the best choice, however not having that kind of money right now you could introduce a cheap plate amp for anywhere from probably 50-400$

Do a search at parts express. com for "plate amp"

 

[mulester7]

....in a passive sub, it could be an 8 ohm subwoofer element, but it probably is a 4 ohm like Jaxvon said....the best you can get from home equipment, imo, is a 4 ohm passive sub getting hit with 2 ohm bullets from a strapped amp....I've tried low end every way 'till Thursday, and that's what I've always liked the best....you'll lose 1/2 the damping factor, but the authority, oscillations, and pop are WELL worth it....

.....some of you guys are too hung up with a fan on the back of an amp....when your amp get warm enough for it to kick on, you're going to be listening at levels well beyond a tiny fan on the back of an amp 10-20 feet away, even moderately listening....Crown makes some very good amps in the 3-4 hundred range.....

....edit....that second one Jaxvon suggested fires two ohm bullets....bunch of 'em....for $249....again......

http://www.musiciansfriend.com/srs7/g=live/search/detail/base_pid/480696/

 

[j_garcia]

IMO, it depends on what type of controls the passive subs have, so I'd wait until I knew that. If the subs have no controls for phase, x-over, etc... I'd go with a plate amp that has them. If they have the controls, then any amp should do the trick.

 

[edwelly]

IMO, it depends on what type of controls the passive subs have, so I'd wait until I knew that. If the subs have no controls for phase, x-over, etc... I'd go with a plate amp that has them. If they have the controls, then any amp should do the trick.

Using the amp you suggested, couldn't he run the sub outputs from the 3805 to the amp and use the 3805 to control the phase , x-over, level, etc???

 

[majorloser]

IMHO I think you should "bite the bullet" and look for a used Crown or maybe a Marantz monoblock on Ebay. Marantz makes some good (and compact) amps. I don't believe the plate amp will really suit your needs.

Do a mono amplifier search on Ebay and see what you can dig up. (Parts Distress sells Crown to get an idea what new price is)

As far as your center channel problem, the speakers are supposed to all "match" (so they say). Shouldn't be a problem. Just try to place the front channel tweeters at the same height. Helps balance front imaging.

Man, $100 for ten speakers and two subs........
Must have taken advantage of a crack head.

 

[j_garcia]

Using the amp you suggested, couldn't he run the sub outputs from the 3805 to the amp and use the 3805 to control the phase , x-over, level, etc???

Sort of. You can control most of the stuff (x-over, not sure about phase) and level should be able to be adjusted on both the receiver and amp, but plate amps are designed to power subs and usually have at least minimal protection circutry and are designed to handle the load of a sub.

Marantz monoblocks are pretty easy to come by and are fairly stout. I'm actually looking at buying a friend's passive sub and I may pick up another mono to power it.

 

[annunaki]

The Behringer A500 Reference amplifer would work great for some passive subs. It is inexpensive and has balls to boot. 230 watts rms x 2 at 4 ohms, or 500 rms x 1 bridged at 8 ohms. It does not have a fan either (quiet) but has very good heat sinking. Check it out here: http://www.partexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=248-749

 

[jaxvon]

Beat ya to it annunaki

 

[j_garcia]

I saw those Behringer amps in the new flyer. Looks like they were measured at 1kHz only. Think they will really make decent amps? (I would expect so from Behringer). That's cheaper than I can get a monoblock for and it has free shipping, and I also need to order some other stuff from them...

 

[annunaki]

I just hooked one up last night for a customer of mine. It is running five, yes, 5 pairs of speakers through an impedance matcher. Seems to power them well. I have to upgrade it though to a Europower amp. After 8 hours at full tilt the thermal protection started kicking in. I need something with a fan for them (customer). I will be hooking it up in my home system soon. I can let you know how it does.

 

[Sheep]

What about the amp in the bass shaker package?

I'm sure you can get one of those. Pumps out 2100 watts into 4 ohms, I think. If that amp was my son, I'd name him Beef cake.

If you can't get the amp by itself, you can always throw the bass shaker at someone and say "you can really feel it eh?"

SheepStar

 

[lbjazz]

Thanks for all of the input. I am finally going to see the speakers Thursday evening so I'll know a little bit more then. The Behringer amp several of you have mentioned looks like it will be great, especially for the price. My only concern is if the sub is a 4 ohm model. I think there's a chance that it may be a 6 ohm speaker but I won't know until I see it. If that is the case, do any of you know of an amp similar to that particular Behringer that is stable at 4 ohms? Once again, thanx for the input, it is GREATLY appreciated.

 

[lbjazz]

I've seen and heard the speakers. I'm 95% sure that the sub is a 6 ohm job. The speakers are a bit too bright for my tastes but for the price . . . Anything is bettre than what I had before (nothing) and will do fine for this poor college kid. Now I just need an amp that is stable at 6 ohms. I guess I could just run one side of that Behringer amp and it should give me enough power as my house is just fine sitting where it is. Ah, decisions.