Need advice on my setup
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New member Username: BabolimpPost Number: 1 Registered: Apr-07 | i'll start by saying i'm no guru at this stuff, so i could use all the knowledge you audio buffs have to offer. at the moment this is what i have: - 4 speakers - 4 channel amp + wiring kit - head unit i plan to get a mono bloc amp and a sub. i've run into a few obstacles so far. firstly, my headunit only has 1 pair of RCA outs - 3 would be optimal in my case. the second problem is that my 4channel amp has no RCA outs, which means i can't simply use 2 RCA splitters at the head unit and run the mono amp via the 4 channel amp. i need to find a suitable course of action. i was thinking that i could get a mono bloc amp with an RCA output. basically, have an RCA cable go from the headunit to the mono amp. then have 2 RCA splitters go from the mono amp (assuming theres 1 pair of RCA outs) to the 4 channel amp, which will power the 4 speakers. i heard that this may cause ingine noise, but do i have any other options? |
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Gold Member Username: CarguyPost Number: 6119 Registered: Nov-04 | If you want to be able to fade, then you will need a new HU. If not you can get LOC for the 4 channel amp, and use the existing RCA from HU for the sub amp. Probably your best option. |
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New member Username: BabolimpPost Number: 2 Registered: Apr-07 | thanks for the reply Isaac. what do you mean by fade? i am familiar with music fading in/out, but i don't think that's what you meant. i googled loc - it's a "linear optocoupler", correct? still, i am confused as to what it does and where it fits in the system... as far as i can understand, you're saying connect HU to mono amp with an RCA cable, and i'm guessing the LOC somehow connects the HU to the 4 channel amp? |
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New member Username: BabolimpPost Number: 3 Registered: Apr-07 | bump |
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Gold Member Username: Nd4spd18Southeast PA Post Number: 1637 Registered: Jul-06 | He means adjust the fader setting front to rear. And in any case, I agree that replacing the HU would be the route to take. |
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Silver Member Username: OlegSanta Monica, CA USA Post Number: 936 Registered: Nov-04 | Shaun, here's the breakdown: LOC is a line out converter. It convers the speaker level outputs of your HU and converts them to low level pre-amp outputs, which you can connect to your amps using RCA cables. It probably isn't a good idea to use RCA output of a subwoofer amp b/c those outputs are probably not full range (you'll need full range for the 4ch amp). Not sure if anyone's done this, but you can just use your single set of pre-amp outputs from the HU and use 3 sets of RCA splitters lol The ghetto way. Split first line in 2, then split each of those in 2 for a total of 4! Of course now you can't fade (shift music from front to back and vice versa). You also can't control subwoofer level from the HU. Ideally, you'll need a HU that has 2 sets of RCA outs and 1 set of sub outs. Is new HU plausible for ya? |
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New member Username: BabolimpPost Number: 4 Registered: Apr-07 | thanks oleg, that helped me alot to understand wtf is going on. to be honest, i didn't want to have to upgrade the HU, as 1) it was a gift and 2) i don't think i'll get too much for it if i try to sell it (receipt was not kept). upgrading the HU will most likely break my budget. as per your advice, i'll scrap that idea for the mono amp. as for the mass splitter method, i think you meant use 4 RCA splitters, which'll create 3 RCA pairs. i think doing this will create too much noise and maybe some other issues? i'm no physicist though so i don't know the REAL effects of doing this or if it's really going to compromise my system at all. i'll still be able to fade from front+back to subs... lol. as a simpler option, what i am now thinking is to just have the back 6*9s and the sub (bridged) running from the 4 channel amp. ill have 2 rca splitters for the HU and just have the front speakers run off the HU's inbuilt amp. the best option for me looks like the LOC. i'll just have to become a little more versed on how it all fits together. - LOC creates another set of RCA outs for the HU - that pair of RCAs is split with 2 splitters to make 2 pairs which will run to the 4ch amp - the original HU RCA outs will go to the sub amp i hope this is right! |
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New member Username: BabolimpPost Number: 5 Registered: Apr-07 | something like this LOC i think? http://cgi.ebay.com/ebaymotors/PAC-OEM-2-OEM2-4-CH-Adj-Line-Level-Output-Convert er-NEW_W0QQcmdZViewItemQQcategoryZ38636QQihZ007QQitemZ170101019629QQrdZ1QQsspage nameZWD2V |
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Silver Member Username: TurnmatPost Number: 143 Registered: Feb-07 | ok i had a JVC HU and it only had one set of RCA pre-outs so what i did i split the pre-outs and than split them again so i now had three RCA pre-outs. This worked great for me i didnt have any noise or other problems. The only think is if you do it this way you should get a line driver (i didnt and everything worked great for me) I would say try the LOC first though |
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Gold Member Username: CarguyPost Number: 6122 Registered: Nov-04 | Shaun, that LOC sounds like it'll work for you. It is a 4 channel LOC, so you should be able to fade Front to Rear. The RCA from HU can then be used with sub amp. |
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Silver Member Username: OlegSanta Monica, CA USA Post Number: 947 Registered: Nov-04 | Shaun, I think Isaac is right, but first I have to ask him this. Does using LOC sacrifice quality? Because I know high level outputs produce more distortion - does LOC take care of that? If so, then it's better using it for the sub amp and then use splitters for for the 4ch amp. |
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Gold Member Username: Nd4spd18Southeast PA Post Number: 1647 Registered: Jul-06 | " Does using LOC sacrifice quality? " Yes " Because I know high level outputs produce more distortion - does LOC take care of that? " No. Once there is distortion in the signal, it's there to stay, you can't magically remove it. As the saying goes, "garbage in, garbage out". And that is precisely the reason why on every install I do I will avoid using LOCs at all cost, and will go to whatever length necessary to replace the HU. |
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Silver Member Username: OlegSanta Monica, CA USA Post Number: 949 Registered: Nov-04 | Ok Shaun, if you absolutely can't get a new HU, use splitters for the 4ch amp and LOC for the sub amp - distortion is a lot less audible in low frequencies. |
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New member Username: BabolimpPost Number: 6 Registered: Apr-07 | after all this discussion i hate to go back on what i originally said, but i've decided to change the HU and put off getting the Sub and mono amp. main reasons being the quality going downhill with every option i choose on the old HU, and 2nd reason being that i wouldn't mind some of the extra functionality and looks of a new HU. i've decided on the panasonic DEH-P6950IB head unit. it has 4V on 3 RCA preouts with ipod direct control *drool*  http://www.pioneer.com.au/products/car_entertainment/CD_Tuners/DEHP6950IB/index.html |
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Silver Member Username: OlegSanta Monica, CA USA Post Number: 959 Registered: Nov-04 | I can't seem to be able to find the premier unites on the pioneer website... But here's one: http://cgi.ebay.com/Brand-New-Pioneer-Premier-DEH-P790BT-Low-Low_W0QQitemZ330108 831657QQihZ014QQcategoryZ39752QQrdZ1QQcmdZViewItem Premier units are said to be better quality than regular pioneer units. This one's $335 shipped - great deal. It has all the same features you want, but with 5V pre-outs. What's your budget anyway? |
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New member Username: BabolimpPost Number: 7 Registered: Apr-07 | the thing is buddy, i'm in australia  i'll need a unit that is suited for our radio frequencies ie a unit build for australian standards. all the mid-high end units for our market (pioneer range) have 4V preouts... even the most expensive is the same. i'm not entirely sure why, as i've noticed the upper end kenwoods feature 5V preouts. in any event, i feel that 4V is "good enough", considering it's the ONLY letdown i can see for this HU. pricewise? i'll be sniping one of them on ebay for around $250-90AU pickup. thats about $210-40US, alot better than $335US~ my budget? i'd like to get away with < $280AU, 300 absolute max. |
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Silver Member Username: OlegSanta Monica, CA USA Post Number: 963 Registered: Nov-04 | some panasonic, pioneer, kenwood,jvc, and eclipse have 5v pre-outs. top of the line eclipse have 8v. if it's the price, go with what you can afford. |
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New member Username: BabolimpPost Number: 8 Registered: Apr-07 | when i was in store, the sales guy said that pioneer used to have 6.6V on their top line stuff (i think..? maybe he was talking about kenwood though i forget). however, too many were sent back due to people's amps melting. i guess the australian sector decided to cover their @sses and lower the preout voltage. according to him, the highest available preout voltage for the australian market is now only 5V. so i'll stick with the 6950 :D |
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Silver Member Username: OlegSanta Monica, CA USA Post Number: 965 Registered: Nov-04 | amps were melting b/c gains on the amps weren't set correctly. the higher the pre-out voltage, the lower the gain has to be set. all those newbies were setting them too high, overdriving the output stage of the amp - bam, too hot! but 4V is good, you won't notice a difference going to 5V |
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Gold Member Username: Nd4spd18Southeast PA Post Number: 1706 Registered: Jul-06 | I would stay away from HUs with preamp voltages higher than 5 volts. You'd be surprised how many amplifiers cannot handle 8 volt inputs....... |
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Silver Member Username: OlegSanta Monica, CA USA Post Number: 974 Registered: Nov-04 | True, but then again, if you do get an 8V deck, you'll need spend sometime looking for a high quality amp that does accept 8V input - it's not easy to find, but not impossible. |
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