Phoenix Gold Phorum

I know it's possible to run a ZX450 bridged into a 2 Ohm load, but what sort of consequences will it have for sound quality?

To give you some more detail - I'm currently trying to work out which of my amps I'm going to use for what. For midbass I'll be using a pair of Focal 13KS mini subs per side, which have a nominal 5.2 Ohm impedance. I'd like to use my ZX450 bridged up to run these, which will give them around 250W per pair, with a final load of around 2.6 Ohms.

Ideally I'd like another ZX500 to match my sub amp, which will give them similar power whilst having an easier ride, but they're a bit hard to find over here.

Another option is to use my pair of ZX350's, either bridged up for silly power, or one driver per channel for less power but arguably better SQ, but that might leave my mids & tweets underpowered by comparison (4x75W from the ZX450)

What to do, what to do....

you will loose much of the headroom that the zx amps provide running it at 2ohms mono.

Well that's what I thought, but it seems to be at odds with the FAQ

But there is a bright side to all this. Remember I said that the excess current demand had to last longer than 100ms. The dynamic peaks in most music last less than 20ms. So the circuit never has a chance to effect the power supply voltage for musical peaks. All this means that the amp IS allowed to make more power with musical peaks while continuous power remains about the same. You could say that the "headroom" of the amp is increased.

If you want to run the amp 2 ohms bridged, go for it. Just understand that it will run slightly hotter and will pull more current from your car to make those musical peaks (add more capacitors and use thick gauge power/ground wire). I wouldn't recommend running it 1 ohm bridged. The amp will shut down (red LED) if the output current gets too high (looks like a shorted speaker).

It can support 2 ohms bridged but it will run hotter and be less linear (slight reduction in SQ).

You also should be running 2 ohms on both sides of the amp, to avoid sending 4 channels worth of power supply through two channels. For example if you have 2 ohms bridged on the rear channels (1 ohm stereo), and 4 ohms stereo on the front channels, the load imbalance will send a lot more power to the rear channels, causing them to fail earlier. It sounds like you are already doing this, so you should be good to go.

Would you consider running just one midbass per side? At most you'll be gaining about 3 dB by adding the second woofer.

And a ZX500 would obviously be perfect. Would be nice if you could find one.

Thanks, that's pretty much what I thought / feared.

The sides of the amp will indeed be running 'in balance', so no worries on that score.

If my doors weren't so restrictive on space and mounting depth this wouldn't be an issue as I could go for a single larger midbass. I wanted Ti9's, but as well as being very hard to come by, they may struggle to play high enough to meet the 3" mids in the A pillar. Larger kick mounted mids are pretty much out of the question due to all the cars electrical system being centred down there

I'll experiment with a single Focal, as the slight loss of volume may be worth it for the better control and SQ, but I'll keep on hunting for another amp.

Finding any ZX500 is hard enough, but since I'm looking for a 10/10 V2 to match my other, it's nigh on impossible

How about active from the ZX450 to the components?

FWIW I have a couple ZX500s sitting around and can ship to UK. None are 10/10s, Caps replaced though. I can take photos if interested.

The ZX500 can run 2 Ohm bridged.

I might click some pics of my Burb install to show you how I did my ZX450 and ZX500 install.

That's my other 'low power' option Pillow.

ZX450 running the mids and tweets, and a pair of ZX350's running the midbass (one driver per channel).

That will give me the easiest load all round, with everything being run at 4 Ohms, but overall power output would be lower than my other option:

A ZX350 on mids and one on tweets, ZX450 (or preferable ZX500) running midbass.

I could well be interested in an amp if the price is right, and here's a picture to give you an idea how it'll all be laid out under a false floor.
(H700 is now black to match the DD5)





I have a thing for symmetry!