Four 12's or just three?

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lukeman269
Posts: 442
Joined: Sat Sep 11, 2010 5:18 am
Location: Minnesota

Re: Four 12's or just three?

Post by lukeman269 »

Zeropoint, Thanks for the input!

So a fuse up at the main battery will not suffice? I think I currently have an 80 amp fuse up front for the main power wire, and I have an extra battery in the rear by my zx500 which I fused 8 inches from the battery. Do you think I should run one more fuse block with a 50 amp fuse just for the zx500?

As for the current output, these subs sound excellent in this box and this amp dishes out adequate power to get them pumping out some, "make your vision blurry" bass. I do agree that just two of these in a ported enclosure would have been the optimal choice for output, but I do like the look of three woofers better IMO and I love the way sealed setups sound vs. ported. Especially since I listen to a variety of music and not just rap. The ported boxes tend to be too boomy and the box would have had to be about 1.5 cubic ft bigger for just two of these ported. The manual suggests a 2 cubic ft box per woofer tuned at 34 hz. Add a slot port or a couple of 4" aero ports, some bracing and sub displacement and we're at 5 cubic ft. Whereas right now I am only at 3.5 cubic ft gross with this current box. This is ultimately why I chose sealed vs ported.
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Jacampb2
Mad Scientist
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Location: Beaverton 48612

Re: Four 12's or just three?

Post by Jacampb2 »

PG recommended a 50 amp fuse within 18" of the ZX500's power input. The fuse at the battery should be sized to protect your power wire runs from short circuits, not to protect your amplifiers in case of malfunction...

IIRC all the ZX amps except the ZX500 were fused internally.

It is very unlikely that the fuse will keep the amp from blowing power supply transistors. Transistors can fail an order of magnitude faster than a fuse can ever open. The fuse does keep the amp from continuing to burn. Power supply FETs commonly fail shorted drain to source (well actually a 3 way short but the gate burns away fairly quickly) and then they are basically a direct short across the battery. Without proper fusing they will continue to draw current and probably literally burn until they open. This makes a repair much more difficult for all but the most dedicated...
M: M100, M44 for a custom amp project
Zx: Zx500, Zx450, Black Zx350
ZxTi: 4 Zx600Ti's, 1 Zx400Ti
Ti: 5 800.1's & 900.7 for a custom amp project. 1 1200.1, 1 1000.2
Tantrum: 2 1200.1's, 1 600.4, 1 500.2
XS: XS6600
lukeman269
Posts: 442
Joined: Sat Sep 11, 2010 5:18 am
Location: Minnesota

Re: Four 12's or just three?

Post by lukeman269 »

Jacampb2 wrote:PG recommended a 50 amp fuse within 18" of the ZX500's power input. The fuse at the battery should be sized to protect your power wire runs from short circuits, not to protect your amplifiers in case of malfunction...

IIRC all the ZX amps except the ZX500 were fused internally.

It is very unlikely that the fuse will keep the amp from blowing power supply transistors. Transistors can fail an order of magnitude faster than a fuse can ever open. The fuse does keep the amp from continuing to burn. Power supply FETs commonly fail shorted drain to source (well actually a 3 way short but the gate burns away fairly quickly) and then they are basically a direct short across the battery. Without proper fusing they will continue to draw current and probably literally burn until they open. This makes a repair much more difficult for all but the most dedicated...
Good to know! I will order up another fuse block asap!
zeropoint0.5
Posts: 593
Joined: Fri May 13, 2011 12:03 am

Re: Four 12's or just three?

Post by zeropoint0.5 »

lukeman269 wrote:Zeropoint, Thanks for the input!

So a fuse up at the main battery will not suffice? I think I currently have an 80 amp fuse up front for the main power wire, and I have an extra battery in the rear by my zx500 which I fused 8 inches from the battery. Do you think I should run one more fuse block with a 50 amp fuse just for the zx500?

As for the current output, these subs sound excellent in this box and this amp dishes out adequate power to get them pumping out some, "make your vision blurry" bass. I do agree that just two of these in a ported enclosure would have been the optimal choice for output, but I do like the look of three woofers better IMO and I love the way sealed setups sound vs. ported. Especially since I listen to a variety of music and not just rap. The ported boxes tend to be too boomy and the box would have had to be about 1.5 cubic ft bigger for just two of these ported. The manual suggests a 2 cubic ft box per woofer tuned at 34 hz. Add a slot port or a couple of 4" aero ports, some bracing and sub displacement and we're at 5 cubic ft. Whereas right now I am only at 3.5 cubic ft gross with this current box. This is ultimately why I chose sealed vs ported.
of course !!! see it like this ...the other zx series have an internal fuse. the zx500 doesn't...that's the reason you have to put an external fuse
just within 8 inches before the amp...

it would be the same story for a ms275 , and both zpa's.... no internal fuse, then a external fuse within 8 inches of the amp....

of course on a wire of 18inch no 2 fuse blocks needed..... if the battery is in the back, a fuse just after it will be fine.....

i will give one more advice for the install...try to get yourself a pg bass cube....will give a big difference in output.... :wink:
Last edited by zeropoint0.5 on Sat Oct 01, 2016 7:46 am, edited 1 time in total.
zeropoint0.5
Posts: 593
Joined: Fri May 13, 2011 12:03 am

Re: Four 12's or just three?

Post by zeropoint0.5 »

Jacampb2 wrote:PG recommended a 50 amp fuse within 18" of the ZX500's power input. The fuse at the battery should be sized to protect your power wire runs from short circuits, not to protect your amplifiers in case of malfunction...

IIRC all the ZX amps except the ZX500 were fused internally.

It is very unlikely that the fuse will keep the amp from blowing power supply transistors. Transistors can fail an order of magnitude faster than a fuse can ever open. The fuse does keep the amp from continuing to burn. Power supply FETs commonly fail shorted drain to source (well actually a 3 way short but the gate burns away fairly quickly) and then they are basically a direct short across the battery. Without proper fusing they will continue to draw current and probably literally burn until they open. This makes a repair much more difficult for all but the most dedicated...
good input... if i repeated somewhere you're words, i apoligize.....
lukeman269
Posts: 442
Joined: Sat Sep 11, 2010 5:18 am
Location: Minnesota

Re: Four 12's or just three?

Post by lukeman269 »

I actually have a matching white bass cube I picked up from tricky ricky!!! I just haven't had time to install it yet. I also plan to make covers for the amps under the seats and I have to figure out where to incorporate the cube.
zeropoint0.5
Posts: 593
Joined: Fri May 13, 2011 12:03 am

Re: Four 12's or just three?

Post by zeropoint0.5 »

lukeman269 wrote:I actually have a matching white bass cube I picked up from tricky ricky!!! I just haven't had time to install it yet. I also plan to make covers for the amps under the seats and I have to figure out where to incorporate the cube.
just before the sub amp....if you place it before all the amps, with the gain of it open, you'll hear the hiss sound through you're

tweeters....
lukeman269
Posts: 442
Joined: Sat Sep 11, 2010 5:18 am
Location: Minnesota

Re: Four 12's or just three?

Post by lukeman269 »

Just tested out the bass cube and got my gains set proper and holy crap! I didn't know how much these things helped out. My 12's were pretty weak around 30-35 hz and I got this dialed around that 30hz range and damn! Makes my steering wheel shake on the lows now. I dialed the boost inside the cube down to about 75% so I don't give it the full +15db. Definitely glad I bought this bass cube though. Really gave my subs that extra backbone I was looking for.
ttocs
the Floor Sweeping Hack with Golden Ears
Posts: 14783
Joined: Fri Dec 19, 2008 9:53 pm

Re: Four 12's or just three?

Post by ttocs »

they are like power windows, you will want one on all your systems now. There is a reason after all these years those are still selling like hot cakes..
what else can I say I am a grumpy asshole most of the time.
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