JL 300/4 with Boston S75's?
 

Hello all, i registered my account here a while back when i did my system, but never got around to posting. (Fellow Canadian)

My system is a ext cab truck with 4 boston acoustics S75's running off what ever was the cheapest at the time Sony head unit. And a JL 500/1 driving two boston acoustics 10" G1's.
I ended up finding the JL 500/1 used for 400 bucks just over a year ago. In the future i want to get a better head unit, but its not a priority, so unless i find a good sale or used one it probably wont happen for a while.

Looking in the same classifieds, i found
Im decently dumb at car audio stuff, i wired my system, but had a buddy of mine do all the settings (his dad used to be a audio store manager), but he has moved, and i no longer have his advice. I found another guy selling the same stuff for 700 bucks total, so im thinking i could sell the 500/1 and make a hundred bucks or so off it, and use the 300/4 on my system.

Will the 300/4 work with my Boston S75's? If the 300/4 is too powerful, can i tone it down so it does not blow my speakers(then when i get around to it, getting speakers to use the full potential of the amp?)

What your thoughts?

I would plug his 500/1 into where my 500/1 is to make sure it worked, but is there any way to test if the 300/4 works?

Thanks

Rob

No one?

You'll sell the jl 500/1 for $100?

Naw, considering local prices, i could sell it for a hundred or so more than what i would pay for it, helping to pay for the 300/4.

I just need to know if the 300/4 will be ok with my speakers, and how to test if it works.

i would buy if you'd sell it :s prices in saskatchewan are wayy too high...

The 300/4 is a great amp. You'll be more than pleased with it.

I just realized, my deck has 1 set of sub pre outs (used by my current 500/1) but it does not have any front or rear pre outs. Can i just plug RCA's into the pre out on the back of my 500/1 (that uses the sub pre out), then run a splitter to make it go into the front/rear RCA's on the 300/4? Big quality lose? Will it even work running a amp for speakers off a "sub pre out"?

Or am i out of luck unless i get a new deck?

Ouch, ya your pretty limited. The 300/4 doesn't have any RCA outputs either. You could use the 500/1 output, but would still only have one RCA. You could set it to 2ch and still run all 4 channels, just won't have front to rear fade.

Sorry for the wrong info, i just found the book for my head unit, and it says i can change the one set of RCA pre outs to either "sub out" or "rear out"

So from reading around, can i set my deck to "rear out", run a RCA to my 500/1. Then run a RCA from the pre outs on the back of the 500/1 into a splitter (Assuming i can get one) and then run each into my 300/4?

What deck do you have?? Even if it only has 1 set of outputs, you should be able to shut off any Xover in the deck to give you a full-range RCA output.

The outputs on the 500/1 can be set to HP mode and the frequency dialed in on that amp.......a single set of RCAs to the 300/4 will feed all 4 channels there and you can use the HP filters in the 300/4 to fine tune the sound for the mids and highs....:smokin:

HTH

Its a sony CDx-GT310

You can do it, I'd just look into a deck as the next upgrade. The 300/4 and 500/1 are great amps, but your going to need a different deck to get the most of them.

Use the front out on the deck to feed the front channels of the 300/4.....leave the rear out set as rears with no xover function in the deck.....split the outputs, use 1 pair for the rear channels on the 300/4 and the other 2 for the 500/1.....wiring this way gives you the ability to fade your fronts and rears and the remote gain for the 500/1 helps with the bass output level. You will need to spend some extra time setting the levels, you don't want the subs to disappear if you fade the sound all the way to the front......:smokin:

I have no front outputs, ONLY a rear, or sub.

(googled my deck)

Right now it is set to sub

He's saying to connect the RCA (rear) to the front channels of the 300/4 and set as full range or rear.

lol now im totally lost

Set your deck to rear and make sure it is allowing all frequencies to pass. Use 2 splitters to make 2 pair of rca's from the one. Connect one pair to the 300/4's front channels and place on 2CH. Adjust the settings for your highs. Run the other pair to your 500/1 and adjust for sub. :smilie_da

HTH

Don't feel too bad, I could have sworn I read somewhere that you had 2 sets of RCAs on your deck......:dunno::laugh:

You'l have to do it the way Paul told you above......you will still have to set all the speaker levels at the amps anyways, but your ability to control the relative levels between them from your dash is toast......:eyes:

A deck with more outputs will give you more control but it's not required to get good sound out of those amps....once you set the system up (or tune it) it will sound fine.....:smokin:

HTH

ahhh Thanks guys! Make perfect sense now!



Using this 300/4 should give me better quality sound that just using my deck to run the speakers right?

When i go to buy it, can i flip the filter to low pass, and plug the 300/4 into my subs to make sure the amp works? (just use the fronts input/output kinda thing to make sure it works)

Going from the Sony deck power to a 300/4 will bring those speakers to life......you haven't really heard what their capable of yet, but you're about to.....:D

If you want to test it, power it up, put it in 2ch mode on the inputs and verify you get sound out of both sets of speaker terminals. Use the HP and LP switches to confirm the Xovers work. Then switch it to 4ch mode and repeat, moving the inputs and the speaker wires to the rears and confirming proper signal path switching inside the amp.....:smilie_da

HTH

:O i suspected after lessening around that i was not getting the best quality, but my engine + exhaust is also not too quiet, so i assumed that was just playing with my head.


Do all that, with the amp connected to my subs? (wont hurt em switching from low pass to high pass?)

Not at all, you're just confirming that the amp works the way it's supposed to.....as long as you can hear the difference when you change the filter setting it's all good.......:smilie_da

HTH

Ok cool!

Im gonna give the guy a call right away, i have 4 gauge wire ran to my 500/1, now my subs are only rated up to 400 RMS, and my speaker wont take all the power of the 300/4, so i don't need either of my amps to run to full 100% power.
Can I just put a distribution block(assuming its way cheaper than new wire) at the end of my 4 gauge, and run another 4 gauge to each amp?
Or should i run another 4 gauge(maybe just 6?) from the battery to the new amp?




You guys have been a big help! :appl::smilie_da

You can use a distro block. You just won't find many that are 4ga in and 4ga out. Likely it will be 2ga in or bigger with 4 ga out. The 300/4 is a solid 75rms x4. It'll do them Bostons some good. :) Just be sure when switching from LPF to HPF that your not cranking the gain. You should hear low level voices from your sub. It won't destroy it, just not good for long periods of time. For the little testing time, you should be good. If your even still a little worried, bring some old crappy speaker thats sitting around (old factory one) and use it for the testing.

Good luck, they are some great amps.

Ahhh good idea thanks! I will grab 2 of my old speakers!


But will a single 4 gauge be big enough to feed both amps? (not sure if under powering them can hurt them)
If not, what size would you recommend re-run to feed both? (via a dist block)

I called the guy last night, meeting him after work today, so ima go put some wire ends on my old speakers right now.

Your 4 ga should work in the short term, IMO you should look into upgrading to 2ga. I was using 2ga up until I bought the JBL then I had to upgrade. With 2ga, I was running a RF 800.4 and 800.2 so about 1300rms with no supply problems.

Still buy the distro, just put your 4ga as the input for now.

Just picked em up! Everything about them worked, ended up paying 420 for it all, as the screw heads for the speaker wire's are basically all stripped on the 500/1. Looking at it, it looks like i can open it up, loosen off the nuts at the back, and remove the main board, allowing me to remove the old screws and put new ones in.

Can i buy placement screws?
Are they normal threads, and i can just buy a same threaded screw from a hardware store?
Is it as simple to replace as it looks?

I just spend a few minutes google'ing and ebay'ing JL hex screws, JL stripped, etc and have not found any useful info.

Best place to start is a JL dealer.....they may have some of the screws you need sitting on a shelf out back.......failing that, they can contact the Canadian Distributer Gemsen and see if they can order you new ones. If you're going to pay that much for amps, a few bucks for the right screws will keep them looking nice.......:smilie_da

HTH