Why no sub-out on 2ch. preamp?

[begbie]

I noticed this on some Rotel models and a few other brands that they don't have a sub-out. Shouldn't they ?

[Zero]

If the pre-amplifier has two pre-outs, just use one of the pre-outs...

[begbie]

Makes sense. Though I thought I read the pre-outs were for an external processor? Or am I getting myself all mixed up here ?

[dcarlson]

If it's just a 2ch preamp, it should only do 2 channel.

It's not made to process a signal. It's your choice wether you want to run a sub or not.

[dragon1952]

You would have to run interconnects from the preamps pre-outs to the sub line-in and then interconnects from the sub line-out to the external amp in order to incorporate a sub into a 2 channel system. You could also connect the external amp to the preamp and then run speaker wires from the external amp to the sub speaker line-in and then from the sub speaker line-outs to the speakers.

[begbie]

thanks, I think I'm getting it?! But if a manual says it can be used to pass the signal to another source than is it okay to send that signal to your sub ?

Probably shouldn't sweat about it but just curious though.

[organ]

Use a Y-adaptor. It has one male and two females. You'll be able to run two sets of interconnect from the single output. I suggest getting high quality Y-adaptor. Check monstercable.com, they have a very nice one.

Maurice

[dragon1952]

There are some pre-amps with sub outs....I've read about them in my internet travels here and there. In fact there was an H/K PT2300 that sold on ebay tonite for $105 that had them. Some newer ones do also, just can't think right now.

[Zero]

Gentlemen,

Am I missing something here?

I am on the verge of purchasing a pre-amp with two pre-outs.

One of the pre-outs will go towards the main amp, the other, towards the sub.

Have I been living under a rock? I've always thought this was possible.

Not attempting to hi-jack a thread here...but it has peaked my curiousity at a very critical purchasing time..


Sean

[dragon1952]

ATC......you are right on. You can certainly do that if you have two line outs.

[George Grand]

And unless you have an outboard cross-over unit, your going to be feeding a full-range signal to BOTH the sub-woofer AND your main speakers. Not a great idea.

One of the reasons for employing a sub-woofer, is not to get super deep bass, but to relieve your main speakers the trouble of reproducing low frequencies that they probably can't reproduce anyway. There's all kind of benefits to that.

You might have to use speaker level connections to your sub from your power amp, and then feed your main speakers a speaker level signal from the sub. There's no reason it wont work, and is an intelligent way to do it. Running the sub AND mains at full range is not.

George Grand (of the Jersey Grand's)

[Zero]

Dragon,

Thank you for the reaffirmation, felt I was loosing my mind for a second.

George,

You bring up a valid issue which has plauged my mind since I began this project of mine. I only hesitate on purchasing more wire due to the fact that I am not certain the Ixos is what I will stick with. One of the goals is not to throw away cash, and until I find the wire that suits me, I will just weigh the options until funds allow for expansion.

Regards,

Sean

[Dr. Spec]

Originally posted by George Grand
You might have to use speaker level connections to your sub from your power amp, and then feed your main speakers a speaker level signal from the sub. There's no reason it wont work, and is an intelligent way to do it. Running the sub AND mains at full range is not.

George Grand (of the Jersey Grand's)

Agreed - it's the only way to do it when there is no sub out and you need to high pass the speaks.

Unfortunately, it will require the amp to send a full power signal to the subwoofer. You won't reap the benefits of internal filtering before the amp stage like you would with digital BM in a pre/pro or AVR. Amps always run cooler, distort less, and have more dynamic range/headroom when relieved of the high-current bass duties.

Doc

[Zero]

At 250w *clean* bridged, I hope not to loose *too* much..

I have heard some amps perform better with bridging, while others falter..

[tryrrthg]

Originally posted by George Grand
And unless you have an outboard cross-over unit, your going to be feeding a full-range signal to BOTH the sub-woofer AND your main speakers. Not a great idea.

One of the reasons for employing a sub-woofer, is not to get super deep bass, but to relieve your main speakers the trouble of reproducing low frequencies that they probably can't reproduce anyway. There's all kind of benefits to that.

You might have to use speaker level connections to your sub from your power amp, and then feed your main speakers a speaker level signal from the sub. There's no reason it wont work, and is an intelligent way to do it. Running the sub AND mains at full range is not.

George Grand (of the Jersey Grand's)

not completely true... REL uses a full range signal to BOTH mains and sub. They claim that you will get a more seamless transition from mains to sub by allowing your mains to gradually roll-off and have the REL come up from underneath the mains. REL has the lowest crossovers that I know of. Allowing the crossovers in the low 20's.

I think that without a sub crossover like REL running mains that can go into the upper 20's (or even 30's, since most sub crossovers stop at 35 or 40hz) full range will cause some problems. but running standmount speakers full range and bringing the sub up from under the standmounts can offer a terrific transition from speakers to sub.

[tryrrthg]

EDIT: damn double post...

[Dr. Spec]

If you bridge the amp (if it has that capability), you will reduce it to a single channel output. Not sure what you are getting at here??

Doc

[pjdami]

B&K PT5 two channel pre-amp can do it.

It has a high pass output at 80 hz, low pass at 80 hz LFE for sub though it is fixed, mono output L + R for full range to the sub (use sub crossover) and a set of full range outputs for the mains as well.

It's the main reason I went with a B&K preamp; that and B&K's excellent sound and reputation for making good mid-fi gear.

Paul

[RuSsMaN]

Originally posted by Dr. Spec
If you bridge the amp (if it has that capability), you will reduce it to a single channel output. Not sure what you are getting at here??

Doc

Doc, I think he is looking at using two AMC amps bridged. (100x2 or 250x1).

Cheers,
Rooster

[VR3]

Originally posted by tryrrthg
REL has the lowest crossovers that I know of. Allowing the crossovers in the low 20's.

@_@ My M&K does like 120-20hz. You can cross it over from 120hz all the way down to 20hz.

[dragon1952]

You might have to use speaker level connections to your sub from your power amp, and then feed your main speakers a speaker level signal from the sub. There's no reason it wont work, and is an intelligent way to do it.

I don't know if this is generaly true or not but I found this while searching for various methods of incorporating a sub in a 2-channel system:
RE: connecting sub-
"Using the "Speaker level" inputs requires some care, since this usually involves connecting it in "parallel" with other speakers, and therefore generally reduces the impedance of these connections putting more of a strain on your receivers amplifier."

link=http://www.ramelectronics.net/html/howto-av.html

[RuSsMaN]

Originally posted by Vr3MxStyler2k3
My M&K does like 120-20hz. You can cross it over from 120hz all the way down to 20hz.

Cross it over at 20Hz? That's a hoot, considering that sub has almost ZERO useable output in entire first octave. ;)

Cheers,
Rooster

[VR3]

Originally posted by RuSsMaN
Cross it over at 20Hz? That's a hoot, considering that sub has almost ZERO useable output in entire first octave. ;)

Cheers,
Rooster

I never said it played that loud, I said you can cross it over there.....jeez, chill....;)

[RuSsMaN]

It's all good young buck, I have *three* powered, and *one* passive sub in use in my humble abode, and only *two* of those can hit 25Hz (room loaded) at a level thats remotely useable.

Cheers,
Rooster

[Dr. Spec]

Cross it over at 20Hz? That's a hoot, considering that sub has almost ZERO useable output in entire first octave.

Sid got owned.

[tryrrthg]

Originally posted by Vr3MxStyler2k3
My M&K does like 120-20hz. You can cross it over from 120hz all the way down to 20hz.

Why are you rolling your eyes?!? I said REL is the only sub I KNOW of that crosses over that low. I don't know anything about M&K... You could have just told me that without being a smart ass and acting like I'M the dumbass!

[VR3]

Dont take that serious man, Cmon.....I just like that smiley - really - AIM should have it. MSN has a really cool one. Don't worry about it......gah! Everyone is so uptight around here!!!!!!!!:D

Doc,
Yep! I'm OWNED!

Russ, I need a new Subwoofer.....lol

[tryrrthg]

Originally posted by Vr3MxStyler2k3
Dont take that serious man, Cmon.....I just like that smiley - really - AIM should have it. MSN has a really cool one. Don't worry about it......gah! Everyone is so uptight around here!!!!!!!!:D

No biggie, it just came off the wrong way. water under the bridge my man.

Originally posted by Vr3MxStyler2k3
Russ, I need a new Subwoofer.....lol [/B]

You and me both! :D But I need a new amp first!

[VR3]

I plan to get the SVS 20-39 PCi. Just need the $$$$$!!

[dragon1952]

My M&K does like 120-20hz. You can cross it over from 120hz all the way down to 20hz.

Cross...over....at.....20....Hz Wha?! Huh!?
What kinda sub would one own that they would set the x-over at 20Hz!?!?

M&K must stand for "M"akin' it up' & just "K" iddin' !