[TJHUB]

I don't really think it's a great idea, but one in which could work for my situation.  However, it doesn't work and I don't understand why.

Basically I'm trying to connect the sub to both my 2-channel preamp and my Onkyo receiver.  My preamp has 2 sets of volume controlled outputs, the first set works with its HT-bypass feature, but the second set goes dead in bypass mode.  I connected a Y-cable on the second set of outputs to combine both channels into one and ran that to the sub.  Works perfectly.  I then connected yet another Y-cable so that the single RCA from my preamp and the LFE out from my receiver could both be connected to the sub.  The preamp works fine, but the receiver's LFE is dead.  If I disconnect the RCA cable from the second Y-cable, the receiver's LFE works.  As soon as the center probe of the RCA from the preamp touches the Y-cable, the LFE goes dead again.  Why is this happening?  The preamp still works with the receiver's LFE connected.  I don't get it.

Thoughts?

[JohnR]

Perhaps the receiver has a resistor in series with the output whereas the preamp is being driven directly by a solid state device. Regardless, something like this and a few RCA-6.5mm adapters would be a better solution - http://www.behringer.com/EN/Products/MX400.aspx

Edit: here's one that has RCAs: http://www.parts-express.com/pe/showdetl.cfm?Partnumber=245-044

[jdbrian]

Is the preamp turned off when you try to use the reciever? A common way of muting the outputs during power on is to have a relay that shorts the outputs and a delay at turn on. This shorts out any turn on transients. In this case it would also short out the reciever output. It is not a good idea to connect 2 outputs directly together. It may work, but you will usually end up with distortion or possibly damage to the output stages. Some sort of switch box would be a better solution.

Brian

[TJHUB]

Is the preamp turned off when you try to use the reciever? A common way of muting the outputs during power on is to have a relay that shorts the outputs and a delay at turn on. This shorts out any turn on transients. In this case it would also short out the reciever output. It is not a good idea to connect 2 outputs directly together. It may work, but you will usually end up with distortion or possibly damage to the output stages. Some sort of switch box would be a better solution.

Brian

The preamp is turned off when I tried using the receiver.  Is that the issue?  The second outputs are turned off when the preamp is in bypass mode or turned off (automatic bypass mode).  The first outputs switch to bypass mode and the seconds ones are turned off.  Are the second ones being shorted out when in bypass mode?  Is this what causes the issue for the receiver? 

The preamp does have a delayed turn on feature.  It takes about 20 seconds to allow the tubes to power up for it turns on the outputs. 

Thanks for the help thus far guys.

[MaxCast]

Can you run the pre out to the L in on the sub and the sub out on receiver to the R in on the sub?

[TJHUB]

Can you run the pre out to the L in on the sub and the sub out on receiver to the R in on the sub?

That's what I did with my previous sub, an SVS PB13-Ultra.  Unfortunately, the SubMersive only has a single balanced input. 

[Speedskater]

I think that this problem is covered in this paper:

Why Not Wye?
http://www.rane.com/note109.html