Subwoofer Input Boost?

[jagdriver]

I'm running a Yamaha RX-V2700 and am splitting the subwoofer with a Y-adapter at the rear of the chassis. The first sub run goes to the home theater powered sub in the family room...no problem. The second run goes upstairs to another powered sub in the master bedroom. Alas, the output from the upstairs sub is very low. Is there some gizmo that lets me boost the preamp input on this line, to be positioned between the Yamaha and the upstairs subwoofer?

 

[MDS]

The sub pre-out on the receiver has a channel trim just like the other channels so you could just boost that a bit to get a hot enough signal to the upstairs sub but doing so will throw off the calibration for the main room (assuming you calibrated to reference level or some level of your choosing). You would then have to compensate by turning the volume down on the sub in the main room. You could also possibly leave the sub channel level on the receiver as it is and just turn up the volume on the upstairs sub.

If none of that turns out to be acceptable such that both subs get the volume they need, then the only gizmo you could use between the receiver and the upstairs sub is a pre-amp/volume control and you turn the volume up on the pre-amp. That pre-amp could be another receiver if you don't have or want to purchase a dedicated pre-amp.

 

[tinidus]

There is a music equipment company called ROLLS who makes some nice little gizmos. I have one of their MINI-MIX VI and I use it often when I need to turn a level up. They are small and pretty cheap if I remember correctly.
I would try what MDS recommended before I bought a gizmo though. I would use another receiver that is not in use.

 

[Adam]

MDS said in his first paragraph the things that I'd try first. If those fail, my thoughts would be:
1. Make sure that you're using a good cable for the run to your bedroom (certainly use shielded cable).
2. You can buy distribution amplifiers for RCA cables. I just wanted to mention those, but I don't know the end result on the signal because they don't have a volume control (at least the ones that I've seen). Using a pre-amp, like MDS suggested, is great because of the volume control. However, if you could find a distribution amp for cheap, it might be worth trying out (just start off with the volume on the sub turned all the way down and work your way up).

 

[jagdriver]

The sub pre-out on the receiver has a channel trim...

...then the only gizmo you could use between the receiver and the upstairs sub is a pre-amp/volume control and you turn the volume up on the pre-amp. That pre-amp could be another receiver if you don't have or want to purchase a dedicated pre-amp.

1) Where is the subwoofer channel trim located? On the back of the receiver?

2) If I go the pre-amp route, how would I go about making the correct connections?

 

[MDS]

1) Where is the subwoofer channel trim located? On the back of the receiver?

You should have level adjustments on the remote but they will be 'on-the-fly' adjustments (meaning they revert back to what they were when you turn off the receiver) unless you start the test tones and then adjust the levels. When the test tones are playing you can cycle among all of the channels.

2) If I go the pre-amp route, how would I go about making the correct connections?

Sub pre-out to any line level input on the pre-amp/receiver. If you use an old receiver, a logical choice would be to use the CD or Tape input as they are audio only inputs. You can use a Y adapter to split the sub pre-out into two and feed the left and right inputs of the CD input but it won't really matter as the sub will sum the two channels to mono and then amplify it.

 

[TLS Guy]

I'm running a Yamaha RX-V2700 and am splitting the subwoofer with a Y-adapter at the rear of the chassis. The first sub run goes to the home theater powered sub in the family room...no problem. The second run goes upstairs to another powered sub in the master bedroom. Alas, the output from the upstairs sub is very low. Is there some gizmo that lets me boost the preamp input on this line, to be positioned between the Yamaha and the upstairs subwoofer?

Your problem is that unbalanced high impedance connections are not designed to carry signal over a large distance. 25 ft is bout max and that's pushing it.

The correct engineering solution is to convert to a low impedance balanced 600 ohm line at the receiver output with a transformer. Then you can convert back to the to unbalanced RCA with another transformer, best, or "float" the balanced line at the sub. Run good quality 600 ohm balanced microphone cable with XLR connectors between the transformers.

Good quality transformers are available for this task from Radio Shack.

And at he sub end this.

You can run the signal a huge distance without loss or degradation this way.

It is to be preferred to boosting.