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The following is from a friend on another forum:

"If the RCA shields for the left and right channels are directly connnected (~0 ohms between them -- with no RCA signal cables plugged in), they are NOT fully balanced.

You need to be careful when driving a strong signal (speaker level or preamp level from a source with a ±15v supply) into the input of an amplifier. If the amp is off or shuts down for some reason and the signal drives the input of the front-end op-amps above the power supply input of the op-amp (which is essentially at 0v since the amp has shut down), the front-end op-amps can be damaged.

Some balanced inputs REQUIRE a dedicated ground connection between the signal source and the amp. Without it, the amp may oscillate which could cause damage to the amp or to the speakers. Always monitor the output of all channels of the amp with a scope when experimenting".

I could not find any info as to wether or not the MB Quart RAA series amps can take a balnced input but you can measure between the left and right RCA's as noted above to check.:thumbsup:
Hey thanks I'll break out the meter and try that!
 

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Discussion Starter · #22 ·
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I just found out that the alpine V12 MRD-M301 can accept the balanced signal directly from the stock head unit without an adaptor. I measured the rca jacks with a multi-meter first and they were not connected so i decided to give it a try. I have mine set to the 1-8 volts selection on the front and it works fine. after some tweaking of the settings it sounds good with a single JL 12W3v2-D2. Maybe this means that all of the newer Alpine V12 MRD amps can accept a balanced input directly?:thumbsup:
 

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I have an Alpine PDX 5 and I was curious about it accepting Balanced signals so I called Alpine. They said no it does not!
 

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So I'm still confused, what does it mean when you say go directly into the stock deck? My amps only input is from rca cables, well in order to run rca cables I would need a LOC, correct? I have the Alpine V12 MRD-605. I havn't hooked this up yet so I am curious...
 

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Discussion Starter · #27 ·
So I'm still confused, what does it mean when you say go directly into the stock deck? My amps only input is from rca cables, well in order to run rca cables I would need a LOC, correct? I have the Alpine V12 MRD-605. I havn't hooked this up yet so I am curious...
you would cut one end of your rca's off and connect the wires to the output of the factory head unit where it comes into the factory amp. there are many places on this forum where it is shown. just search and it will come up. your v12 should work fine without the loc.
 

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many people here have gone directly into pdx amps without issues.
I am not disputing that only relaying what Alpine told me. Can anyone with a PDX 4 or 5 that has done this PM me. I am in a dispute with an audio store who sold me "more than I need in cable and equipment" and I am trying to prove to them that the AudioControl LC6 they insisted on to hook up my PDX 5 was not needed.
 

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I saw this thread and I'm currently doing my audio install. I'm using a sven4 to run the signal from the factory HU (HK) to my amp. Right now its giving me problems. I am using a Mcintosh MC431 and by the sounds of it I can plug the HU signal directly to the amp w/o using the sven4 LOC? If that is the case how will I wire the HU wiring to an RCA so I can plug to the amp....any thoughts?

JD
 

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yes you can fry the input stage.

Some amps have seperate inputs for BDL and/or High Level inputs. My Xtant has a jumper that needs to be moved to allow for BDL and another jumper for the input voltage range but only has RCA inputs for all the input options. My US Amps switch automatically and still only have 1 set of RCA's for connecitons.Check your manual before connecting.
 

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yes you can fry the input stage.

Some amps have seperate inputs for BDL and/or High Level inputs. My Xtant has a jumper that needs to be moved to allow for BDL and another jumper for the input voltage range but only has RCA inputs for all the input options. My US Amps switch automatically and still only have 1 set of RCA's for connecitons.Check your manual before connecting.
My kicker dx700 only accepts RCA inputs. I lost the manual but saw a switch for high level input. Im thinking if i switch it this setting I can then solder the speaker wires to an rca cable and plug it in directly without any problems.
 
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