Alright, I have a Alpine MRV-F340. 55W per each of the 4 channels, which I'm trying to bridge to run a set of Infinity Kappa components (60.5cs).

I'll get to the nitty gritty later, but so far here's the problem: When I adjust the balance all the way to the left, the right speaker becomes silent. But when I adjust the balance to the right, both speakers continue to output sound. Here's how I have it set up.

The headunit (Alpine CDA-9513) is connected to the amp through the 'front' set of RCA cables; left to left, right to right. At the amp, I've got a Y-connector on both channels. One cable (both inputs from Y-connector) goes into the Ch1(white) and Ch2(red) L/R input pair on the amp. The other cable goes into Ch3 and 4. Then I've selected 1+3/2+4 on the input switch on the amp. I've then connected one speaker's '+' terminal to Ch1's '+' terminal on the amp and the speaker's '-' terminal to Ch2's '-' terminal. For the other speaker the '+' terminal on Ch3's '+' terminal and the '-' to Ch4's '-'.

Here's the amp's manual:
http://www.stylestandard.net/oswego/Doc/0/...mrv-f340_om.pdf <<---- useless, unless you'd like to navigate through alpine.com to get to it.

I've concluded the problem must lie in the amp's configuration, because I can switch the RCA inputs on the amp and it has no effect, whereas if I switch the speaker outputs from the amp, the speaker that can be balanced off changes.

Anyway, if you folks have any experience with this sort of situation, advice would be appreciated.

 

I've checked the doc link to the manual (and it doesn't work). Here's what I'd like to reference:

The input selector settings on the amp.

a)Setting this switch to "1 + 3/ 2 + 4" will
sum the CH-1 and CH-3 input and send
it to CH-3 while the CH-2 and CH-4 inputs
are summed and sent to CH-4.
b) Set this switch to "3/4" to have the inputs
of CH-3/4 accept independent input
signals. An example of this application
would be the use of a head unit with
dual pre-amp outputs.
c) Setting this switch to "1/2" will send the
signal at the inputs of CH-1/2 to CH-3/
4 of the MRV-F540/MRV-F340. This
eliminates the need for "Y"-adaptors
when using a head unit with a single
pair of pre-amp output.

Unfortunately this information is contradicted later in the document when it depicts a 2 channel setup with a MRV-F340 (I'm assuming bridged by the connection of the speakers to the amp), but it's using the 3/4 input selection.

In any event, all I want to do is get the bugger bridged and the channels separated .

 

I believe (not 100% sure tho) that all 4 channels need to be separated.

So, you need 2 sets of rcas running:

CH1 - Front Left
CH2 - Front Right
CH3 - Rear Left
CH4 - Rear Right

THEN, you bridge the lefts and rights together.

Try this and see if it works.

 

can't get to the manual -- my old registration for their tech is apparently expired (or i can't remember the pw), and it's too late for me to bother with it tonight.


try this -- ditch the Y cables. send your left signal to channel 1 and the right to channel 2, and retest.

what you're experiencing indicates you've got a shared ground between the two speakers.
also double check that one of the speaker wires is not going to ground. you can do this by disconnecting the speaker wires from the amp. make sure they don't touch chassis. then measure the resistance of each speaker lead to the body. if any of them read anything other than infinite, you've got a cut wire somewhere. (and yes, technically, you only need to measure 1 lead from each speaker, but it doesn't hurt to do all 4, and it takes very little time.)

 

PJK3, you can get to the manual by navigating from the Alpine main site, to Support, and then somewhere in there they'll prompt you for some login info, but they'll also have an option to continue without logging in.

Anyway, I'll be in a meeting all today, but as soon as I can get out of here I'll try the suggestions so far. I'd think that because I can switch which speaker becomes silent by switching the speaker outs, its not a problem with the speaker cables. I wish their instructions were a little more clear. In those instructions above it says the summed outputs are output on the amp on Ch3 and Ch4. But if you look on the amp's outputs themselves, it says that the "bridged" outputs are Ch1-Ch2 and Ch3-Ch4

 

I've at least tried to separate the two RCA shielding from touching while using the Y-connectors. If for whatever reason they were to make contact this sounds like it would fall into the case you described.

 

The "input channel" switch refers only to channel 3 and 4. That's why when you fade left, the right speaker becomes silent (left ch. source is channels 1/2) and when you fade right, both speakers are still audible (the source of left channel is channels 1/2 and 3/4). Your problem should be fixed if you change the selection switch to ch. 3/4 only.

by the way, I don't think your y-connectors are a problem at all. It sounds like your wiring job should work fine.

EDIT: if you look on page 18 of the manual, you can see exactly what i'm talking about; they have the system wired exactly as you describe with the only difference being the input switch is set to ch. 3/4.

 

I'll doublecheck that connection and reverify, but I'm pretty sure that I've tried that configuration a few times to verify that it does not fix the problem. Again, it seems a bit misleading in the manual to say that the 'summed inputs' of a L/R pair are sent to speaker outputs that aren't consistant with what is printed as 'bridged' outputs on the amplifier itself.

I've never bridged an amplifier before, but I understand conceptually what its doing. I'd assume you'd have to let the amplifier know that you want two RCA inputs 'summed' (one actually inverted and used as a ground reference). This selection intuitively would be percieved as the 1+3/2+4.

I've got my speaker outputs connected exactly as shown on that diagram on page 18 of the manual. I've set it up before without bridging the amp, but I'd like to take advantage of the feature because my speakers can handle almost double the RMS output power than the amp can deliver via its normal configuration.

As you can see on that same diagram, it show's Y-connectors used as well with the 3/4 input selection. Does the speaker automatically detect, based on speaker connections that it needs to bridge itself?

 

I agree with PJK3. The splitters should not be necessary. You should have 1 RCA plug for the front right, and one for the front left. RCA's are not like speaker wires (where you need a + and a - ). Remove the Y-splitter and plug the left channel into CH 1, and the right channel into CH 3. Then bridge 1-2 and 3-4. You should only have 2 RCA plugs to plug into the amp, as you are running only 2 channels. The problem is that you are running 2-channels into 4-channels of the amp.

Try removing the Y-splitter and just using CH1 and CH3 for the inputs. If those dont work, try CH1 and CH4, then CH2 and CH3, then CH2 and CH4. One of those combos will work (depends on which channel the bridged signal is pulling its source signal from).

John

 

It can be done either way - with or without Y splitters. I would go with the "no splitter" option

Follow everything in the top image, but use the 1/2 Input setting from the bottom image.