Amp wiring question

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Well past my big speaker phase of youth but I did score a deal on a very moderate sub and amp combination for my summer cruiser. Reading the factory manual for the amp I’m a little confused. It’s listed as a 2/3/4 channel amp and bridgable. How would one wire this to one single voice coil sub? Also the manual shows two 30A fuses wired in parallel on the battery power line. This seems odd to me, can I replace it with a single larger fuse and or why size?

 
If you're using a SVC sub, bridge two of the channels together by connecting to the A channel negative and B channel positive, either left or right. Connect your RCA input to either L or R channel.

Yes, a single 60a fuse on the B+ wire is fine.
 
I don’t think it will run as a mono amp. Note the line between the upper L+ and lower L- as well as the upper R- and lower R+ Those look like the bridges to me.
 
It'll run mono just fine. The lines are indicating your speaker connections. Just use one or the other.
 
Originally Posted By: 14Accent
It'll run mono just fine. The lines are indicating your speaker connections. Just use one or the other.


It will run 2 channel bridged but how will it run mono?
 
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Some amps can be bridged, some cannot. It depends on the topography (basically, the type of circuit used) or the configuration (some amps are already bridged internally to get higher power output ... they cannot be bridged a second time).

Are you positive the two fuses are wired in parallel? That sounds strange and doesn't fit any known purpose. Have you confirmed it with a DMM? Are you sure they are not individual fuses each bank of power amplifiers, or are they two fuses wired in series?

The difference will determine whether you need to maintain two 30A fuses or can substitute one 60A fuse. If you can substitute one 60A fuse you will still need to jump the empty fuse socket. In the end I would just forget about the whole fuse thing and carry on as configured. Getting it wrong carries a slight risk of fire or a definite risk of blowing fuses, if the amp would even work at all. I don't see the point.

There is a 3-channel configuration. That would probably be achieved by taking the bridged 2-channel L or R and cutting the bridged configuration, leaving two individual L and two individual R channels. Now they can bridge two of those four into a third channel.

All of the above taken together seems to indicate you cannot bridge the amp to one channel, due to reason 2 (it's already bridged in 2 channel mode).

EDIT: Upon further examination of the speaker output wiring notes silkscreened on the unit it definitely contains four amplifiers (L + L and R +R), with two L and two R, which are bridged in 2 ch mode (L + L and R + R) and although I don't see any silkscreen about 3 channel mode, I'm sure in the manual it would be L + (L+R, bridged) +R configuration. So, no, your mono dreams are over with this amp.

You could simply not use one channel, and configure it in mono mode that way. In fact it's your only option. Most Solid State amps are fine with one channel unused. In that case you would only use the RCA input on the channel you intended to connect to a sub (or whatever) and leave the unused channel RCA unconnected.

Sub frequency signals are usually present equally in both L and R channels of the source, so there is no real penalty in only using one channel as long as the frequencies are truly sub or very low bass ... about 120 Hz or less; above 120 Hz they do become directional.
 
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If you're confused about the wiring diagram silkscreen, it goes like this:

L+ top row to L- bottom row, bridged 2 ch mode (Channel 1)
R- top row to R+ bottom row, bridged 2 ch mode (Channel 2)

Note the little bars connecting the above configuration, including one little bar connecting the words "bridged" to the above wiring.

So, if you intend to use this amp, connect it as above, but only with one channel (you choose, 1 or 2, but not both). Leave the unused channel speaker outputs and the RCA input of that channel unconnected. Doing so will give you the highest power from each channel (the used and unused ones). Without a manual you can't be positive of the 3-ch mode, as it's not indicated on the silkscreen. Regardless, it would offer the same power in the "middle" channel as the above configuration, so there is no need to go there.
 
Fuses are wired in parallel because a 60 amp fuse is not made in that physical form factor. The "mega fuse" is more expensive than two small ones.

Like the others said you would use only half of the amplifier to drive a single speaker. This is likely OK if you don't want it really loud.
 
Thanks all! I feel like a gommer asking but its just been so long. Anyways, the amp is an older Pioneer GM-4000F which will be connected to a JVC Arsenal KD-AHD59 which does have sub output (unfortunately they are stereo outs). Basically what I'm hearing is that if I bridge channel A to B using either left or right speaker outputs it should work just fine with my SVC sub (its a Insignia of unknown model/specs as I haven't pulled it from enclosure to check yet). I by no means need a huge thumper just want a little more balanced sound in my cruiser.

Oh, and the manual clearly shows parallel 30A fuses at the battery connection. Very weird.

Edit: Here is the three channel mode. I wonder if I can just run the mono output from channel B....


 
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