# LOC vs HL Amp inputs



## robert j (Mar 30, 2018)

Hi guys and gals.

If I buy an amp with HL imputs, is that as good as say an audiocontrol LC7i? Strickly from the input side of things. I know the LC7i puts out about 6.5v.

I saw a video installer say that LOC in is better than straight into amp from speaker leads.

Thanks.


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## minbari (Mar 3, 2011)

if you can find a good quality amplifier, then it prolly wont be any different. good luck though. almost all amplifiers that have HL inputs are garbage.

if cost is an issue. you dont have to get the LC7i. the LC2i is much cheaper and will do he job. just use y-adapters to go to multiple amps.

just dont get the $25 passive LOCs. complettely worthles.


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## What? (Jun 5, 2008)

I use RCA to speaker wire adapters like JL XD-CLRAIC2-SW or Alpine KCE-SP2R and go directly into the RCA inputs on JL or Alpine PDR and up amps without issues. I try not to use any LOC (passive or electronic) if I can. If the factory signal is too high, I need summing, or the factory EQ is crazy, I will use a FiX.


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## Sine Swept (Sep 3, 2010)

For simple add a sub situations I like the LOC with remote turn on circuits. Some vehicles make it difficult / time consuming to find a switched power source. Obviously it varies with different situations / gear.


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## edub13 (Jun 19, 2015)

A local shop installed a PAC 90 LOC when they added amp and sub to my wife's car. The PAC 90 has a remote level control. They installed it with the gains maxed out so the level control was super touchy and the sub wouldn't blend with the front at all because it would just make ****ty "brrrbrrrbrrr" sounds.

I re-did all of that when I added a 4-channel amp. Used the high level input capability of the amp that they installed and added the accessory remote level control to the amplifier. It sounds soooooo much better now.

I have no clue why they installed it the way they did, because it was just as much work as the way I did it but it sounded like garbage.


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## Autonomous (Apr 29, 2014)

edub13 said:


> A local shop installed a PAC 90 LOC when they added amp and sub to my wife's car. The PAC 90 has a remote level control. They installed it with the gains maxed out so the level control was super touchy and the sub wouldn't blend with the front at all because it would just make ****ty "brrrbrrrbrrr" sounds.
> 
> I re-did all of that when I added a 4-channel amp. Used the high level input capability of the amp that they installed and added the accessory remote level control to the amplifier. It sounds soooooo much better now.
> 
> I have no clue why they installed it the way they did, because it was just as much work as the way I did it but it sounded like garbage.


Either they didn't know what they were doing, it they were waiting for you to complain so they could make some money "custom tuning" your system. 

Either way, seems like they lost your future installation business!

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## edub13 (Jun 19, 2015)

minbari said:


> if you can find a good quality amplifier, then it prolly wont be any different. good luck though. almost all amplifiers that have HL inputs are garbage.
> 
> if cost is an issue. you dont have to get the LC7i. the LC2i is much cheaper and will do he job. just use y-adapters to go to multiple amps.
> 
> just dont get the $25 passive LOCs. complettely worthles.


Why do you say that almost all amplifiers that have HL inputs are garbage?
This seems like a pretty common feature across a pretty broad range of amplifiers.


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## minbari (Mar 3, 2011)

edub13 said:


> Why do you say that almost all amplifiers that have HL inputs are garbage?
> This seems like a pretty common feature across a pretty broad range of amplifiers.


Name some

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## edub13 (Jun 19, 2015)

minbari said:


> Name some
> 
> Sent from my LGLS992 using Tapatalk


Based on Crutchfield descriptions, there are like 200 models that they sell that accept HL input, to include the following:

JL Slash v3, HD, VXi, XD, RD
Kicker KX
Mosconi D2
Focal FDP
Audiocontrol amplifiers
Alpine X series
Rockford Fosgate Punch

I don't know if their listings are accurate, or if those amps are any good, but it seems to be a common feature.


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## minbari (Mar 3, 2011)

edub13 said:


> Based on Crutchfield descriptions, there are like 200 models that they sell that accept HL input, to include the following:
> 
> JL Slash v3, HD, VXi, XD, RD
> Kicker KX
> ...


High level in this case is not speaker level. Just means they accept a level higher than 5volt.
Don't think any of those have speaker level inputs 

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## edub13 (Jun 19, 2015)

minbari said:


> High level in this case is not speaker level. Just means they accept a level higher than 5volt.
> Don't think any of those have speaker level inputs
> 
> Sent from my LGLS992 using Tapatalk



I see what you're saying, but an 8 or 10 Volt signal is pretty hot, isn't it? The Focal FDP will accept a 19V signal, that's pretty darn speaker level to me.
Nominally speaking, 8V into a 4 Ohm load is 16 Watts, and most headunits (unless they're some sort of Gucci factory premium thing) probably don't put out much more than that if at all, do they?


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## robert j (Mar 30, 2018)

minbari said:


> High level in this case is not speaker level. Just means they accept a level higher than 5volt.
> Don't think any of those have speaker level inputs
> 
> Sent from my LGLS992 using Tapatalk


There is a distinction between High Level and Speaker Level inputs? I thought they were the same!

JL Slash has speaker level inputs.


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## minbari (Mar 3, 2011)

I have owned 3 slash amps none had speaker level.

Do you connect speakers to RCAs? I wouldn't. 

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## edub13 (Jun 19, 2015)

minbari said:


> I have owned 3 slash amps none had speaker level.
> 
> Do you connect speakers to RCAs? I wouldn't.
> 
> Sent from my LGLS992 using Tapatalk


I wouldn't connect speakers to RCAs, but I damn sure did solder some RCAs onto speaker wire to jam into the inputs on this sub amp last week. Now you have me questioning my judgement, Ima go out and measure the signal that the factory stereo throws....


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## minbari (Mar 3, 2011)

if that is how you do it, then cool beans, but that is a serious impedance mismatch. the HU has a 4 ohm output impedance and your amplifier has a 22kohm input impedance. (give or take)


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## edub13 (Jun 19, 2015)

minbari said:


> if that is how you do it, then cool beans, but that is a serious impedance mismatch. the HU has a 4 ohm output impedance and your amplifier has a 22kohm input impedance. (give or take)


I dunno, man. 
That connection method is in accordance with the manufacturer's literature, and the signal voltage straight out of the head unit is within the acceptable range listed in the same literature for that amplifier.


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## minbari (Mar 3, 2011)

edub13 said:


> I dunno, man.
> That connection method is in accordance with the manufacturer's literature, and the signal voltage straight out of the head unit is within the acceptable range listed in the same literature for that amplifier.


If it works, Do it. Wouldn't be the first time I haven't seen something before lol

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## miniSQ (Aug 4, 2009)

minbari said:


> Name some
> 
> Sent from my LGLS992 using Tapatalk


Helix p-six dsp mk2
All the slash amps
Most of the mosconi amps

And a ton more..you kind of got out over your skis with that comment 


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## RRizz (Sep 4, 2012)

The JBL MSA amps came with the speaker level to RCA connectors


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## minbari (Mar 3, 2011)

miniSQ said:


> Helix p-six dsp mk2
> All the slash amps
> Most of the mosconi amps
> 
> ...




It would appear I am wrong this time. Won't happen again. 

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## What? (Jun 5, 2008)

JL Audio has been discussing problems of passive LOCs and telling dealers to connect directly to the RCA inputs on their amps in trainings for at least a decade.


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