Hardware Review: JL Audio CL-RLC volume controlled preamp

**pcpete** · 11-03-2009, 03:20 PM

More power is always good

...

But if you could provide more info as to brand/model of amp and woofers..plus exactly how you have wired them....series/parallel...ohm rating of woofers etc....

**jessekilner** · 11-03-2009, 05:43 PM

I agree..SPECS will tell all.
the distortion can be anything from not enough power on input side that the amp cant efficiently boost it. The Signal to noise ratio (SNR) and total harmonic distortion (THD) or (Db) as a refrenced also.. the higher this number the more music it reproduces at a lower per volt input. These can be the difference in high quality vs low quality amps. The S.N.R. is where you want to focus for input side as this is where the amp tells you how well it reproduces and amplifies the original "music" without degration. the THD is how much distortion is heard on higher volume for instance a THD 1%

would in perfect world be 1% is pure distortion @ 100 percent not including enhanced effects, so this you want as low as you can go. It's always my first look when buying amps..
Also it can also be wrong wiring type for the amp.. it sounds like your running it 2 ohm load but this can be wrong assumption.. if your amp isnt rated for 2ohm load then it will kick off upon higher volume as this is when the amp's transistors are being strangled, smacked and beaten.. if you had it wired in series your amp wouldnt cut. try unhooking one and see if it still cuts? I bet it don't.. this will tell you if you need to change wiring from parallel to series or buy an amp that supports 2-ohm loads. Another possible problem but unlikly with only 240 watts can be your amp has a protection for low battery voltage when the bass kicks the the amp voltage drops and temporarily goes into protect mode this can be also the case for wrong wiring for the subs as earlier mentioned... if the amp isnt rated for it! Im not sure the output of Xenark screen output but I can asure these Jl boosters will make your input much more cleaner and stronger. I ordered a pair of these yesterday. But rest assure JL leads in automotive audio in SEMA, my wallet proves this..lol
I am willing to make a friendly bet that your amp shuts down because its not rated for your Ohm load and the distortion is too low voltage level input all this points to a low quality amp

**tripzero** · 11-03-2009, 06:26 PM

Okay, i'll get some specs and report back. Sometimes my non-bass sound will go out when it hits really hard, but there is still bass sound... I wondered if the amp was drawing all the power away from the xenarc's amp, but like you, that seems unlikely at only 240watts. When the bass cuts out, it cuts out for several minutes. During my last 700mi road trip, it seemed to cut out for 30mins to 1hr at times.

brb with some specs...

**jessekilner** · 11-03-2009, 06:32 PM

this poor thread has been hijacked..

thats overheating for sure no doubt.. Im leaning towards 2 things its either the load or the thermal paste inside is thin and the thermal resistor is getting hott too fast. when we see those specs and verify your wiring is ok, then I would suggest a trip to a radioshack and get "thermal compound" it;s thick white and messy but it will solve premature overheating issues. I have amp being upgraded and can post a video of how to apply this if it get to that point. I would create a new post..lol

* I just created a thread lets see if it's in demand
http://www.mp3car.com/vbulletin/car-...ml#post1353849

**jessekilner** · 11-03-2009, 07:42 PM

back to the review on Jl's website it claims 7.5VRMS output unclipped! where did you find 5v? Also I was looking in the online manual and it says the 2 uncontrolled outputs are same as original input level?!?.. can you clear this up as Im confused are all 4 outs boosted or is it only 2 of them?

http://mobile.jlaudio.com/products_c...hp?prod_id=446

**tripzero** · 11-03-2009, 08:13 PM

in effort not to hijack this thread any more: http://www.mp3car.com/vbulletin/car-...ml#post1353863

Thanks!

**soundman98** · 11-04-2009, 09:19 AM

??where did i get the 5 volt rating?? i have no idea--edited review(this makes it a even better deal)... i might have seen something somewhere about the rms output being 5 volt-- too bad i can't find it now...

yes, there are 3 audio connections for the cl-rlc-- input, passthrough and variable. the variable output is the audio controlled by the knob, and the passthrough is a output of the unmodified input signal(this would be for if you wanted a sub volume knob in a mulit amp system that you only had one pair of rcas for-- use the pass through for the fullrange setup)

**jessekilner** · 11-04-2009, 10:24 AM

only problem I see with that, is now you have a .2mv from pc and then a 7.5V< so for $110 I can get 4 outs @7.5V, I'm a JL fan all the way but that's alil steep for preamps.. I could in theory buy another 20wx4 amp with nice SNR %THD and use that to boost for possibly lower price without the hassle of splitting and extensions..connect it to high input at the end of the line and walla.. The only reason I complain is I am working on a 7.1 channel setup and this way would be costly,. Too bad I already ordered one..lol guess I find some use somewhere
I would need 4 of these to have leveled input@ 55 for 7.1

**RipplingHurst** · 11-18-2009, 01:15 PM

Just bought mine. Thanks for the reviewer!

**TFCommanderBob** · 11-28-2009, 12:51 PM

A quick, possibly stupid question.

I'd like to be able to control both bass separately and everything as a package. How many of these would I need to purchase to do that and how would I wire it? I'll have 2 pair of speakers (front and rear) and a subwoofer.

RJ-11 wiring with 3 preamps:
Knob1 (master) wired to a 3way splitter which is fed by 2 preamps and a 2way splitter which splits the 3rd preamp between Knob2 (Bass) and the 3way splitter.

Rca wiring: is an obvious 'to each his own' 4.1 wiring

RJ-11 wiring with 2 preamps:
Knob1 wired to a 2way splitter fed by 1 preamp and another 2way splitter which splits the 2nd preamp between knob 2 and the first splitter

Rca wiring: a 2 channel output and a sub output from the pc, sub wired normally, the 2 channel output split into 4 RCAs AFTER the preamp?

The big question: Would that lower the preamp voltage, Or is that ok? This would of course mean no 4.1 audio, but it would have been matrixed 4.1 as my general source would be 2 channel music.

It would of course save me 50$ to only get 2, but I'd rather buy 3 if splitting the RCAs after the preamp ruins (or halves) the preamp signal quality, especially since that gets me 4.1.

Any insight is greatly appreciated! The review is excellent btw, I was hunting for a way to avoid FE volume controls, and this appears to be a great option!