QuestionQUESTION: Hi,
I Originally purchased twin subs and connected to a mono amp. At the time my other 4 speakers were stock. I now want to connect a 4 channel amp to 4 after market speakers. How do I go about doing this? Is there any special things I should look out for? Do I have to connect the two amps together or just treat them completely separate?
ANSWER: Hi,
You have a few different options when it comes to adding a second amplifier.
For the power wiring, you'll need to decide whether your existing amp's power wire is thick enough to support the current requirements of both amplifiers. If you used an over-sized wire originally, you may be able to just add your new amplifier to the circuit. To do this, you need a power distribution block. A distribution block is designed to connect to a large power wire and break it off into smaller outputs. For example, a common type will have a single 4-gauge input and two or more 8-gauge outputs. A "fused" distribution block includes built-in fuse holders for each output; it's always a good idea to install a fuse anywhere you're going from a larger wire to a smaller one.
With this setup, you'll just disconnect your existing power wire from the mono amp and connect it to the distribution block. You'll need a few feet of wire to run from the block to each amplifier. If possible, you should connect the new amplifier's ground wire to the same ground point as the mono amplifier; but this usually isn't critical.
On the other hand, if your existing wire isn't thick enough for the load of both amps, then you can just run a second power wire from the new amplifier directly to the battery. In this case you don't need to connect anything directly between the two amps. Again, ideally they should both be grounded at the same point.
Hopefully your head unit has at least three sets of pre-amp outputs, so you can run separate front, rear and subwoofer RCA cables. If it only has two or one set of outputs, though, you'll either have to use splitters, or connect the mono amp's RCA inputs to the RCA outputs on the 4-channel amp. Not every 4-channel amp is equipped with RCA outputs, however.
The remote wire can be split at any point, or "daisy-chained": connected to the first amp, then another wire from the same remote terminal to the second amp.
Hope this helps!
Brian
---------- FOLLOW-UP ----------
QUESTION: You guys are absolutely fantastic! I honestly expected to get a delayed response if any. So thank you so much for providing this service. I did have a further question to ask regarding wiring and power requirements (Watts, Gauges, Ohms, amps, Impedance, WRMS, VRMS). Also is it possible to include a simple diagram (even hand drawn) and can we upload pics to show?. It would be much easier to illustrate a problem or solution.
Issue:- When I originally installed the twin subs with the mono amp I ran 4 gauge wiring throughout the car.
The Head Unit (HU) has 4xRCA, 2 front and 2 rear for speakers. (Front and Rear Line Outputs). It has 1xRCA for the subs. (Variable Subwoofer Line Output w/Multiple X-over Frequency Setting).
It also has 8 color coded reagular wires, for speakers and 4 wires for Ground,Battery, Power Antenna and Accessory/Ignition. (I will use RCA) No sub backup wire. HU has a 200-Ohm preamp Line Outputs and 2VRMS Line Outputs. (I'm know that these figures are used to calculate some formula so you don't blow speakers or amp BUT not sure how.). Can you help me work out the right specs?
The front speakers are 8”(200mm which is so rare here in Australia. In fact, I rang every audio retailer in sydney and only one shop had them in stock and they were the last. So I don't want them blowing up! ), 3 way split, 25-32Hz Freq response, 4Ohm impedance, 90 Watts @Nominal (300max)). The rear speakers are factory 6” or 6.5”. I still have not purchased yet, but should be much easier to get then the 8”.
The amp on the other hand, I know very little about. Could not find Information on amp (Response cat.AA-0435 4x100WRMS High Power MOSFET Car Amplifier). If anyone does please let me know!
It does have RCA input but your right no RCA output. The confusing part here is, the selection of dials and buttons.
ie: SENS (has a dial turn from) 2.5v – 0.25v How do I know what the right setting is?
X-OVER, has a dial turn for FREQ 40Hz-120Hz, and a sliding switch indicating SELECT [L/H/F]) and finally another dial turn for SUB EQ 0db-18db. All this for both front and rear speakers. My speaker frequency is lower than the min setting here. Will this be an issue?
What is [L/H/F] and what do I set it to?
Should I set the SUB EQ to 0db since I will be using the mono amp for subs?
Lastly the amp has front and rear bridged ports (Line Out). 2 left (L- and L+) and 2 right (R- and R+). Is there a difference between RCA and bridged ports?
Which is the better choice?
Also what would happen if you wired up the two or four speakers, so that they ran off 4 ports only?
Ie: The two -VE wires from rear speakers goto say L- in rear bridge and two +VE wires goto L+ also in rear bridge and then have the two -VE wires from front speakers goto say R- in front bridge and two +VE wires goto R+ also in front bridge. Will there be a difference in sound or power output or consumption?
What is the best configuration to have?
AnswerHi,
I'm assuming you already have your head unit's sub output connected to the mono amp, so you'll just need to connect the front and rear outputs to the 4-channel amp, using two pairs of RCA cables. The speaker-level outputs on the head unit won't be used--presumably they're connected to your existing front and rear speakers, so make sure they're disconnected before the amplifier is hooked up to those speakers. Don't worry about the head unit's output impedance (ohms) spec. The output voltage gives you a place to start when you're setting the amplifier's gain control, but it's not all that important either.
8" speakers are no more common in the US than they are in Australia. Keep in mind that it would be fairly easy to install a 6-1/2" speaker in that space, by building an adapter plate from plastic or MDF. The main advantage to an 8" speaker over a 6-1/2" speaker is an extended bass response; but you've already got that covered with your subwoofers. So don't feel that you're limited to the one available 8" speaker for your fronts; if you find a 6-1/2" speaker you like better, go with it.
I couldn't find a lot of information on your amplifier either, though I did find a few pictures from people selling one. It appears to be a pretty well-regarded amplifier. It looks like they're either made or exclusively sold by Jaycar, so you might try contacting them directly to see if they can provide you with an owner's manual.
I'll try do decipher some of the amplifier's settings:
"SENS" is the input level. It's meant to match the amplifier's inputs to the head unit's output level. Because your head unit uses 2v outputs, you'd probably want to start by setting the amplifier to the 2v setting. You may find you'll need to adjust this, later, to get an acceptable volume range; but chances are the 2v setting will work well for you.
"X-over" stands for "crossover". A crossover is used to filter a portion of the frequency range. You'd use the dial setting together with the L/H/F switch. L = low, H = high, F = full. So, for example, if you set the dial for 80Hz, and the switch for "H", the amplifier would allow frequencies higher than 80Hz to pass through to the speaker outputs, and filter out frequencies below 80Hz. This would probably be a good setting for your purposes, because it would keep the subwoofer-level bass out of the front and rear speakers. That lets the speakers play louder with less distortion, and less chance of being over-powered. Setting the switch for "F" would allow all frequencies to pass, and the setting on the dial would be irrelevant. The "Sub EQ" dial just boosts a subwoofer bass frequency, and you should leave it at 0 in your application.
What you're calling "bridged" ports are the amplifier's speaker outputs. (The "bridged" label is just meant to apply to two of the terminals in each row. A multi-channel amplifier usually has the ability to combine two channels into a larger channel for more power; this is called "bridging", and it's done by connecting a single speaker to the two specified "bridged" terminals. If you were using subwoofers with this amp, you'd want to use the bridged outputs; but in your case, you'll want to look only at the left and right, positive and negative markings under the row of terminals).
In just about any car audio component, RCA jacks are used exclusively for low-level, pre-amplifier signals. The speaker outputs--colored wires on the head unit, and the set screw terminals on the amplifier--are high-level, amplified connections. So it's important not to mix the two. On your amplifier, the RCA jacks are for the low-level inputs, and the speaker ports are the high-level outputs. You'll be using both: input connections coming from your head unit, and output wires leading to your speakers.
The best configuration for your speaker connections to the amplifier is to just follow the markings under the row of speaker terminals. The left front speaker will be connected to the L+ and L- terminals in the "front" terminal row, and so on.
Hope this helps!
Brian
