6 replies to this topic

[miker84]

Hey All,

I've got a noob question regarding my proposed new system - I've searched and searched and am yet to find an answer for my query.

I've got a Fusion fp4-1000x Amplifier which has been rock solid for 8yrs - here are some specs:

- 125watts x 4 @ 4 Ohms
- 500watts x 2 @ 4 Ohms
- 250watts x 4 @ 2 Ohms

Will I have any issues running my 4ohm JL Audio Splits from Ch1&2 and my 2ohm JLAudio W3v3 Sub bridged from Ch3&4?

Can the amp support the mixed ohm output, or will it only run at 4ohm OR 2ohm at any one time.

Thanks in advance!!!

Miker84

[Spink!]

By the looks of it it's not stable at 2ohm bridged mate, this is common for 4 channel amplifiers.

[miker84]

I actually found that 2ohm power spec in another forum post - I had a look at the original amplifier box last night and discovered that the box only lists the amp as being 'stable for 2ohm operation'.

Does this change the situation?

Cheers

[AJ (LOUDA1)]

when you bridge an amp it uses 2 of the channels at half the impedence.
therefore if you bridge 3/4 at 4 ohm it runs each channel at 2 ohm, which your amp is stable for
and obviously if you bridge it at 2 ohm it runs each channel at 1 ohm which not many amps other than misconi's that i know of are stable at 1 ohm per channel, basically your wiring the amp down at too low ohms and will kill it, might be good looking for a 4 ohm sub or maybe a mono block with good power at 2 ohm

hope this helps

[miker84]

Thanks AJ - this clears it up for me.

I used to run a 4ohm sub from 3&4 with no problem - I now understand how this worked.

My new 2ohm sub will turn 3&4 into 1ohm each which in turn will probably fry the amp. DAMN!

Thanks for the help guys

Edited by miker84, 05 February 2012 - 10:47 AM.

[miker84]

After further research it appears that I've been delivered the incorrect sub enclosure. I was supposed to receive JL Audio HO112RDGW3V3
with a 4ohm sub installed.
Instead I've receive the enclosure that contains the 2ohm version of the sub.
Not Happy Jan!
I'll be getting intouch with the reseller tomorrow to rectify the mistake.

So once I get the correct 4ohm sub, my fusion amp should do it's job nicely

2 x 125w to front splits @ 4ohm
1 x 500w to sub bridged @ 4ohm

Thanks again guys for the help!

[AJ (LOUDA1)]

sounds good man