# JL Amp High/Low Switch



## ksears91 (Nov 24, 2011)

I searched but can't find anything. What is considered a high or low volts for the pre-outs. Is 4v considered high or low?


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## ousooner2 (Jan 6, 2011)

what amp are you using?? Most of the time low is around 0.2v-2v-ish


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## ksears91 (Nov 24, 2011)

JL 450/4


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## kyheng (Jan 31, 2007)

Just set it to low and call it the day.... Tested before on high, but it sounds like sh*t..... The high is more for high level input...


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## ksears91 (Nov 24, 2011)

I tested it on high and low and I actually think the high sounds better. Am I doing something wrong?


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## trojan fan (Nov 4, 2007)

ksears91 said:


> I searched but can't find anything. What is considered a high or low volts for the pre-outs. Is 4v considered high or low?


Here you go, taken right from the owners manual



The “Low” position on each “Input Voltage”
switch selects an input sensitivity range between
200mV and 2V.This means that the Input Sensitivity
rotary control will operate within that window. If
you are using an aftermarket source unit, with
conventional preamp-level outputs, this is most likely
the position that you will use.
The “High” position on each “Input Voltage”
switch selects an input sensitivity range between
800mV and 8V.This is useful for certain high-output
preamp level signals as well as speaker-level output
from source units and small amplifiers.To use
speaker-level sources, splice the speaker output
wires of the source unit or small amplifier onto a
pair of RCA plugs.
The output of the amplifier will decrease for a
given input voltage when the “Input Range” switch
is placed in the “High” position. Conversely, the
output will be higher with the switch in the “Low”
position. While this may sound counter-intuitive, it is
consistent with the descriptions above.


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## msmith (Nov 27, 2007)

The manual for the 450/4v2 explains the switch in detail on pages 7-8. The 450/4v2 is identical to the 450/4 in this regard.

You can download it here: 
http://tinyurl.com/d8esfx2

The "low" position is for preamp level signals (200 mV - 2V)
The "high" position is for speaker level signals (800 mV - 8V)

Best regards,

Manville Smith
JL Audio, Inc.


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## DR34M 7H3473R (Feb 25, 2008)

msmith said:


> The manual for the 450/4v2 explains the switch in detail on pages 7-8. The 450/4v2 is identical to the 450/4 in this regard.
> 
> You can download it here:
> http://tinyurl.com/d8esfx2
> ...


what he said  Same on my Slash 300/4v2


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## trojan fan (Nov 4, 2007)

msmith said:


> The manual for the 450/4v2 explains the switch in detail on pages 7-8. The 450/4v2 is identical to the 450/4 in this regard.
> 
> You can download it here:
> http://tinyurl.com/d8esfx2
> ...


There you go...right from the horse's mouth....


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## UNBROKEN (Sep 25, 2009)

msmith said:


> The manual for the 450/4v2 explains the switch in detail on pages 7-8. The 450/4v2 is identical to the 450/4 in this regard.
> 
> You can download it here:
> http://tinyurl.com/d8esfx2
> ...


What about preamp level signal north of 5 volts ?
Been trying to get that answered for a year with no results.


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## jooonnn (Jul 26, 2009)

In my experience, even though my headunit might claim 4 or 5v outs, it never gets anywhere close to that at the other end even at reasonably high volumes.


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## gnesterenko (Mar 17, 2011)

jooonnn said:


> In my experience, even though my headunit might claim 4 or 5v outs, it never gets anywhere close to that at the other end even at reasonably high volumes.


This +1.

The same JL manual actually has a bti of text, something along the lines of "Use the low setting even if the source isa dvertised as high voltage preouts. The high setting is pretty much used only if you are going to tap into speaker level outs."


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## kyheng (Jan 31, 2007)

^Yup, that's right, speaker outputs use High while others use "low".... Still, you can try both of the settings and see how it goes...


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## ksears91 (Nov 24, 2011)

It seems like it sounds better on high.. I don't know..


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## gnesterenko (Mar 17, 2011)

ksears91 said:


> It seems like it sounds better on high.. I don't know..


If it sounds better then use it? But more importantly, make sure you set your sensitivity dial, regardless of what position the swtich is on, to match your speakers. There are many guides on how to do this by ear. Or you could go the JL Audio route as per their manual, which involves using a DMM to measure the voltage on the speaker outs and basically turn the gain up until your reach the specified voltage levels.


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## pionkej (Feb 29, 2008)

Just and FYI, louder is generally considered "better" to an untrained ear. Try setting the gain to 3:00 on low, then flip the switch to high (do this at low volume so you don't come blaming me for blown speakers) and there WILL be an audible output difference. Now try setting gain properly on low, turn it all the way back down, and match that output level on high...I bet the quality is not "better" but the same.


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## msmith (Nov 27, 2007)

UNBROKEN said:


> What about preamp level signal north of 5 volts ?
> Been trying to get that answered for a year with no results.


I have yet to find any preamp level signal, regardless of claimed output, that required the "High" setting. Use the low setting for preamp signals, high setting for speaker level.


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