RCA to 4-Channel Amp question

[nda0602v6]

I want to bridge a 4-Channel amp to run some components up front. Bridging the amp will give me 70watts RMS x 2. Since I only have one-pair of RCA outputs on my HeadUnit, how would I go about wiring the RCA's to the 4-channel amp in bridged mode? Don't you only need to have 1 RCA input on an amp if you bridge? (1-RCA (LEFT) would go to channels 1 and 2 in bridged mode and the other remaining RCA (Right) would go to channels 3-4 in bridged mode)? Is this right or will I need some Y-adapters?

[user1101]

No, i think you spoke correctly. you have a LEFT signal (red RCA lead) and RIGHT signal (white RCA lead). After you bridge your four channel amp, you'll still have two discrete channels - a left and a right. No Y-adapters necessary.

You may have to bridge 1-3 & 2-4 though. That's the only tricky part. It depends on how the manufacturer set up the L-R channel separation.

[edited for spelling]

[ August 05, 2004, 07:07 PM: Message edited by: user1101 ]

[96firebird311]

I'm placing my money on his RCA voltage will then be cut in half. Using Y-adapters will solve this problem. Try it and see for yourself. Plug both red and white into the front inputs and see if that increases volume in the front speakers vs. only red OR white plugged in.

[user1101]

Originally posted by 96firebird311:
I'm placing my money on his RCA voltage will then be cut in half. Using Y-adapters will solve this problem. Try it and see for yourself. Plug both red and white into the front inputs and see if that increases volume in the front speakers vs. only red OR white plugged in.

You could be right, but I don't think so. A Y-adaptor would split the signal in half. So you've got either 2 full L-R signals into half the number of inputs (my solution), or 4 half signals into all four of the inputs (your solution).

I'm not really sure who's right here though. It's definitely worth a test to find out. Keep us posted.

[ August 05, 2004, 02:25 PM: Message edited by: user1101 ]

[nda0602v6]

Thanks guys,

I'm sure its one of the two. I could have sworn I've seen in Audio Magazines where people have used 2 separate amps (running bridged) to power the Left and Right components. I also remember when I looked at the install pics, they only had (1) RCA jack going into each amp. I'm basically doing the same as using two amps by using a 4-channel amp. I'll keep you guys posted.

[96firebird311]

Originally posted by user1101:
You could be right, but I don't think so. A Y-adaptor would split the signal in half. So you've got either 2 full L-R signals into half the number of inputs (my solution), or 4 half signals into all four of the inputs (your solution).

The signal does NOT split in half when using Y-cables. Yes, both amps will see the same voltage, but it's not half. Nor is it the same voltage as if only 1 amp was connected. Why? The headunit's internal resistance. By placing two amps in parallel (y-cables), you half the load placed on the headunit. Typical loss would be about 5% of headunit voltage. With a 4V preout, it would be right around .2V over a single amp config.

[user1101]

i think we're arguing semantics now 96firebird311. Are we talking voltage or current? "Signal" doesn't really mean much of anything besides the waveform shape, which has no bearing here. I should have spoken more clearly.

Also, did we get a verdict on this issue ever nda? A pound of experiment is worth a ton of theory, right?

[ August 12, 2004, 08:44 PM: Message edited by: user1101 ]

[nda0602v6]

Originally posted by user1101:
Also, did we get a verdict on this issue ever nda? A pound of experiment is worth a ton of theory, right?

No verdict as of yet. A deal I had on the 4-channel amp in question fell through. I still plan on doing some experimenting with this issue.

[96firebird311]

Originally posted by user1101:
i think we're arguing semantics now 96firebird311.

I'm honestly not trying to argue. Just discussing. We're all here to learn and build off one another. [img]smile.gif[/img]

Originally posted by user1101:
A pound of experiment is worth a ton of theory, right?

Oh so true! [img]graemlins/rofl.gif[/img]