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Welshsox
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Hooking up sub with Pre/power amp combo

Hi

Im trying to figure out how you would hook up a sub to a system that had a basic pre amp and a basic power amp combo. The preamp would typically have 4-6 inputs and a single pre amp out to the power amp, i know more modern units might have more pre amps out etc but a lot dont.

Could you hook up the sub to the tape out ? is that a valid acoustical thing to do ?

I cant think of another way because you want the sub to receive the L/R channels of a stereo system.

Anyone got any other ideas ?

Thanks

Alan

ethanwiner
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Re: Hooking up sub with Pre/power amp combo

A subwoofer should be used with a crossover. Modern A/V receivers have this built in, and it's called bass management. If you have a regular 2-channel receiver you need an external crossover. Or a sub that has that built in. Many do, but those usually work with powered speakers. You could connect a sub directly to the Tape Out and set its built in crossover to not respond higher than, say, 80 Hz or whatever. But then lower frequencies also go to the main speakers, so you don't get the benefit of lower distortion in the main speakers. And the bass response will probably not be ideal either since you now have two speakers reproducing an overlapping frequency range.

The above can be taken as a long-winded way of suggesting that you consider buying a new receiver.

--Ethan

mrlowry
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Re: Hooking up sub with Pre/power amp combo

Does the sub have speaker level inputs as well as the line level inputs? If so you could use some speaker wire off of the amplifier and run it to the sub. In fact that is the preferred way to hook up REL subs, Thiel also sort of does it this way. They believe that then the sub is "seeing" a signal more similar to what the speakers gets, leading to better blending. Also that makes sure the signal that the speakers get doesn't have to go through an extra set of circuits. Having heard their subs many, many times in quite a few systems they are really on to something. There's no reason that a non-REL couldn't be hooked up this way too. Give it a try and see what you think.

Kal Rubinson
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Re: Hooking up sub with Pre/power amp combo

Take a look at the Paradigm X-30 crossover.

Kal

BillB
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Re: Hooking up sub with Pre/power amp combo

Could the poster replicate having an extra pre-out by using Y-cables?

mjalazard
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Re: Hooking up sub with Pre/power amp combo

Go to Audio Magus and look into their Subline II T-amp sub connector.
http://www.audio-magus.com/SubLine_Subwoofer_Connector_p/slv2.htm
It's a cool little (and cheap too) device that hooks onto the same speaker output leads on your amplifier. It converts the amp-out signal to a pre-out level, without stressing out the amp. You just hook the RCA outs with interconnects to your powered subwoofer or another amp dedicated to that subwoofer. It does not alter the signal or sound to the speakers. We used it with a Single-Ended tube amp driving a pair of Ferguson Hills FH001's and a small Sunfire subwoofer.
This Subline works, of course on T-Amps, as well as other amps.
At $69.00 plus shipping...it's worth playing with.
Mike

eagle
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Re: Hooking up sub with Pre/power amp combo


Quote:
Hi

Im trying to figure out how you would hook up a sub to a system that had a basic pre amp and a basic power amp combo. The preamp would typically have 4-6 inputs and a single pre amp out to the power amp, i know more modern units might have more pre amps out etc but a lot dont.

Could you hook up the sub to the tape out ? is that a valid acoustical thing to do ?

I cant think of another way because you want the sub to receive the L/R channels of a stereo system.

Anyone got any other ideas ?

Thanks

Alan

I think you can't use the tape outs because there would be no volume control to the sub.

eagle
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Re: Hooking up sub with Pre/power amp combo

I believe that the tape out will not be affected by changes in the volume control.

The simplest way is run the pre out into a splitter, then to the main power amp and the subs amp.

absolutepitch
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Re: Hooking up sub with Pre/power amp combo


Quote:
I believe that the tape out will not be affected by changes in the volume control.

Right. That could drive the Sub to high levels depending upon the input sensitivity in the Sub's amp if it's a powered Sub.


Quote:
The simplest way is run the pre out into a splitter, then to the main power amp and the subs amp.

Most likely O.K. I would check the input impedance for the amp and the Sub, as they get paralleled with a simple splitter (Y-cable), unless the splitter has resistors to 'isolate' the two sets of inputs.

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