OK guys, so I ran into a very odd problem a while back with the install on my Z, and unfortunately, bringing it back to the installer did not yield any help.

Equipment consists of a DDX7015 HU, McIntosh MC431 Amp, Focul Utopias, Seas Lotus Sub. I am (trying) to have the amp power the front components and sub, and the deck for the rear fill. All works great EXCEPT, I've got zero stereo seperation on the front!!!! I noticed this initially when I popped in a Lenny Kravitz CD that I'm familiar with, where the right and left channels were recorded independant of one another. The front left speaker is playing exactly the same thing as the front right. Adjusting the fader from right to left mutes the right channel and the left simultaneously. Now, with 90% of the music, frankly it sounds just fine, and if I did not say anything, no one would know. However, it's bugging the hell out of me and I'm ready to try and do something about it.

I've got the rear of the deck exposed at the moment so I can begin tracing wires and what not, but I wanted to ask the experts here if this were an installer error, or if it had something to do with this particular amp not being able to run things the way I'm asking it to? What is confusing me is that in the instructions for the amp itself, there is a tutorial on how to hook the amp up for 3 channel operation, though it shows a McIntosh X Over and using a second MC431 amp to power the "other" channel. Is it possible that this amp won't play stereo 3 channel without another amp powering the other side (that would suck!)?

Thanks in advance guys - I know it's a bit of an oddball question, but any assistance would be great

Adam

 

Q: when you change the balance, what does it do?
1) balance from equal to full left
2) balance from equal to full right

when you change the fader from Front to Rear, it should decrease the sound from both front speakers equally.

-Peter

 

Peter - when I change the balance from equal to full left, I get zero sound. When I change the balance from equal to full right, nothing changes (ie its playing the same volume from both the left and right front channels at once

 

sound like either:
1) from you HU to your amp there is only the Left channel signal (check that the wiring going from the HU to the amp is correct)
2) your speakers are both connected to the Left channel on the amp (check that the wiring from your amp to speakers is correct)
3) your amp is messed up and receiving both channel from your HU, but only supling the Left channel to both speakers (to check if you amp is messed up, you could supply the amp with 1 signal to just the Right speaker IN, and see if both speakers play. then supply the amp with just the Left speaker IN, and see if both speakers play...this will tell you if the amp is taking only 1 of the speaker inputs and outputting that single signal to both speakers)

...from personal expeirence, it's most likey a mis-wiring (#1 or 2) - but I'm nor a professional and am more prone to simple mis-wiring mistakes which makes it more likley that errors are due to me rather than the equipment.

hope that helps.

-Peter

 

Peter - thanks. Ruled out #3. With the amp in 2 channel mode (simplest way to check I think), I can disconnect the right channel or the left channel and get the opposing channel to work

it would then seem I'm dealing with a bad RCA connection or cable?

 

What are you disconnecting, the IN or OUT on the amp?

 

there are 2 sets of inputs (channel 1-2-3-4) and then one set of outs (labelled sub).

I've got the sub outs connected to the sub, and the ins (1-2) connected to the front speaker output RCA's from the headunit.

With the amp in 2 channel mode, I get a nice full sound from the fronts and the sub. With the amp in 3 channel mode, I am not getting nearly as full of a sound from up front however.

If I disconnect the left or right speaker wires from the amp, I can get the left or right speakers to totally not play.

Perhaps it is a matter of the sub only being able to play in mono when being asked to operate in 3 channel mode, and a second amp and crossover really are needed....strange

 

http://ampguts.realmofexcursion.com/...1/outside3.jpg

so let me get this straight, you have inputs going in to 1-2, speaker wires running from the speaker outs, and two wires subwoofer out going to your sub?

 

as of right now it's got inputs going to 1-2, speaker wires from the speaker outs, rca to the sub out(the 80 hzt one you see in the pic) and then 2 speaker wires bridged to the sub speaker connections you see on the right

 

the more I keep going over this, the more I think the amp may be at fault. I've communicated with McIntosh directly a couple of times over the years on other stuff, so I just dropped them an email to get their suggestions. I'm actually hoping it's the amp and not the wiring (the amp can be removed easily - the wiring gets to be a royal PIA to do!)

If anyone's got any suggestions, I'm all ears!!!