# Problem using High Inputs on amp



## drewpage55 (Aug 3, 2008)

I'm having problems with High Inputs.

I have rca's tapping off the rear speaker wires to get sound to the amp. 
When I connect both Left and Right RCA's to the amp, its very obvious by evidence of the sub that something is wrong. The sub seems to flex slowly and doesn't sound good. Only if I leave one rca disconnected does it seem to work, - I say "seems to work" because it seems that I should be getting much more power going to the sub. The amp is a JL 250/1 running a 10 inch polk momo which is rated for 300 watts, 600 peak. Even with the gain pretty much all the way, the bass boost all the way up, and the amp LP filter all the way to 200 Hz its still not pounding like I expect.

Doesn't seem to be a difference if I switch the pos and neg leads around on the rca's. Both rca inputs on the amp seem fine, same result when I move rca's from one or the other, but both connected and theres a problem. 

Please help...


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## tinctorus (Oct 5, 2009)

Thats because high level inputs should be using speaker wire into the speaker wire high level inputs

You are connecting to the low level inputs

Or since you have a jl amp try moving the switch you should have a hi/low level switch

Or just get a line out converter


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## drewpage55 (Aug 3, 2008)

Here are the settings on the amp:


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## Lanson (Jan 9, 2007)

Speaker wire needs to run to an LOC then to the amp.


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## drewpage55 (Aug 3, 2008)

Can you recommend one?


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## drewpage55 (Aug 3, 2008)

So you're saying that I should not use the high input mode but instead get a LOC and use the low input mode?


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## 89grand (Nov 23, 2006)

According to JL Audio, a LOC is not needed to use speaker level outputs. In fact, they suggest exactly as you did, splicing the speaker wires with RCA plugs.

I would triple check your connections, positive of the speaker lead to the center wire of the RCA and the negative wire to the grounding ring. Make sure both are the same way. Use a multimeter if necessary to determine which is which on the RCA plug.


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## tanakasan (Sep 8, 2007)

drewpage55 said:


> Can you recommend one?


^^Navone LOC

Also turn down the bass boost and be sure that you are turning the gain in the correct direction.

Use just one RCA if that's the cure?

Robert


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## tinctorus (Oct 5, 2009)

You could also have reversed the two sets of signals

I would double check your wiring as I didn't realize you had a jl amp and from my experience with them they are usually fine being hooked up just as you did


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## don_chuwish (Oct 29, 2009)

Trying to use the high level inputs on my 300/2 has been frustrating as well. It should work but I got too much noise (hiss). I blame the output of my stock HU tho, not JL. It did make me look around at LOC options however.
I don't recommend what I got, a cheap 4ch from Scosche.

Anyone know if the Maxxsonics MX-?? products are good? They look interesting. For the OP, the MX-3 and/or MX-4 may be on topic: MAXXSONICS - CES 2009

Street prices are a lot lower than MSRP of course.

- D


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## drewpage55 (Aug 3, 2008)

Well it looks like I'm doing things correct according to the JL 250/1 manual.
They say to only use 1 RCA, and to use a Y adaptor to split the signal to both inputs of the amplifier. 

As for the total lack of expected power, the manual also states that the power output of the amp will decrease when the input range is in the High position. That is gay and unacceptable. 

I'm thinking I might have to get a Line Output Converter that converts High voltage to low voltage so I can use the Low input setting on the amp. 

What do you guys think?

The manual can be found here: My Retrevo - My Manuals


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## drewpage55 (Aug 3, 2008)




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## drewpage55 (Aug 3, 2008)

I bought a LOC, and I'm using the low input mode now.
Output from amp is 1000 times better. I have the gain set only 1/4th, and the bass boost at +3, Frequency filter at about 90 Hz. Pounds the crap out of the polk momo if I go much more.

Still no need for a remote wire with the signal sensor turned on.

Moral of the story: JL amps do not do High Input despite what they say. 

Thanks for all your replies.


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## don_chuwish (Oct 29, 2009)

Good news. Which LOC if I may ask?

- D


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## drewpage55 (Aug 3, 2008)

don_chuwish said:


> Good news. Which LOC if I may ask?
> 
> - D


Edge IEC AULOC Adjustable Line Output Converter

It was all I could find in town, ended up getting raped by best buy for about $28. 
http://installedge.com/home/home.asp


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## tanakasan (Sep 8, 2007)

drewpage55 said:


> I'm thinking I might have to get a Line Output Converter that converts High voltage to low voltage so I can use the Low input setting on the amp.


WTG! Congrats on sorting this out!

Gotta be cleaner than any built in high/low section.

Robert


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## don_chuwish (Oct 29, 2009)

drewpage55 said:


> ended up getting raped by best buy for about $28.
> InstallEdge.com


Cool that you got it fixed. $19 for used off eBay or $28 for new from a major retailer... I'd consider the extra $9 well spent.

- D


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## tinctorus (Oct 5, 2009)

drewpage55 said:


> Edge IEC AULOC Adjustable Line Output Converter
> 
> It was all I could find in town, ended up getting raped by best buy for about $28.
> InstallEdge.com


Wouldnt really consider 28 dollars "being raped"

It's actually a pretty decent LOC and of the 400 or so I have used I havent had a problem with a SINGLE one

Plus it has adjustable "gain" controls on the LOC


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## drewpage55 (Aug 3, 2008)

tinctorus said:


> Wouldnt really consider 28 dollars "being raped"
> 
> It's actually a pretty decent LOC and of the 400 or so I have used I havent had a problem with a SINGLE one
> 
> Plus it has adjustable "gain" controls on the LOC


You work for Best Buy. LOL. Sorry but you can buy pretty much anything online for a cheaper price (including shipping) if you look hard enough and are willing to wait.

best buy leaves a bad taste. They never have anything I'm looking for. They won't even sell me a couple of feet of 4 gauge wire.
I was floored when they actually agreed to sell me an LOC.


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## DaveRulz (Jun 22, 2006)

Are you positive that it was the JL amp and not a simple wiring issue? If you had one of your RCA's polarity flopped, the exact problem that you are describing would have happened. 

I've witnessed this myself when I had the positive and negative of one speaker feeding a LOC swapped. You get serious cancellation which results in super ****ty output, but not no output at all. 



> As for the total lack of expected power, the manual also states that the power output of the amp will decrease when the input range is in the High position. That is gay and unacceptable.


You are miss-reading this. What that switch does, is attenuate the inputs so that when you hook up a powerful signal it doesn't blow the input stage. What it is saying, that with a *constant signal*, flipping the switch to high will reduce amplifier output. But this doesn't matter, because if you have a powerful enough signal (such as the speaker outputs from your head unit) you will still be able to get full power from the amp.

My feeling is that you spent money on another piece of equipment in your signal chain that you didn't have to.


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## jeraldobunkster (Nov 20, 2008)

drewpage55 said:


> You work for Best Buy. LOL. Sorry but you can buy pretty much anything online for a cheaper price (including shipping) if you look hard enough and are willing to wait.
> 
> best buy leaves a bad taste. They never have anything I'm looking for. They won't even sell me a couple of feet of 4 gauge wire.
> I was floored when they actually agreed to sell me an LOC.


I work for Best Buy myself in the install bay and the reason they won't sell you a few feet of 4 gauge wire is because corporate for whatever reason doesn't give us spools of wires. Every amp needs to have the Rockford Amp kit. Frustrating for the consumer, even more for the installer when you need a few feet of this or that and don't have any laying around.


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## 89grand (Nov 23, 2006)

DaveRulz said:


> Are you positive that it was the JL amp and not a simple wiring issue? If you had one of your RCA's polarity flopped, the exact problem that you are describing would have happened.
> 
> I've witnessed this myself when I had the positive and negative of one speaker feeding a LOC swapped. You get serious cancellation which results in super ****ty output, but not no output at all.
> 
> ...



I agree with all of this and it's the point I was trying to make, but I gave up and decided the OP could just handle it however they wanted to.


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## tinctorus (Oct 5, 2009)

drewpage55 said:


> You work for Best Buy. LOL. Sorry but you can buy pretty much anything online for a cheaper price (including shipping) if you look hard enough and are willing to wait.
> 
> best buy leaves a bad taste. They never have anything I'm looking for. They won't even sell me a couple of feet of 4 gauge wire.
> I was floored when they actually agreed to sell me an LOC.


Thats is because we dont have just a few feet to sell you "loose wire that is" I know its ****ing stupid

However I really dont consider 28 dollars "getting raped" plus you had it right then and there and didnt have to wait for shipping


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