your choice of amp for 2 woofer 15in

[ostie01]

Hi, have the choice between these 3 power amp to power my 2 15in woofer. What would you keep if you had the choice. Electronically crossed over at 120Hz at 24dB

1- Harman kardon citation 7.1

2 X 450 watts rms @ 8 Ohm in bridged mode
130 Amp per channel in dual mono bridging
THD < 0.03%
2500 watts maximum
weight 70 pounds
http://img162.imageshack.us/img162/5976/71faceqc0.jpg


2 - Parasound HCA-1206

> 350 watts rms
THD < 0.03%
dynamic headroom > 2dB
SN ratio > 118 dB
damping factor > 800
weight 71 pounds
http://img69.imageshack.us/img69/379...hca1206lc1.jpg
http://img60.imageshack.us/img60/609...206backvy7.jpg


3 - 2 parasound HCA1200

600 watts rms mono bridged
40 amp continuous - 57 amp peak
THD 0.03 %
Dynamic headroom > 1.5dB
SN ratio > 110 dB
damping factor 120
weight 38 pounds
http://img124.imageshack.us/img124/2337/hca1200zc8.jpg

Thanks

[parsecaudio]

Hi
A choice is very difficult without to know your speaker.
I have not never listened to these amplifiers,but i think that a bridge amp is not a good solution also for subwoofer solutions, because of very known problems on the phase shifter stage,and for the fact that the signal must pass from two amplifiers for a single signal.

[richie00boy]

Problems on the phase shift/split stage - first I've heard of it. Can you provide some more info?

[parsecaudio]

Hi richie00boy
The little problem on the phase shift is not to regards on his operation,but for the fact that generally on commercial amplifiers the signal on the negative side must pass through an op amp or ,still worse, the signal for the negative output amp is supplied from output of positive amp,applied to the inverting input.The result is a different(even if small)behavior on the negative and positive output amp,for distortion,bandwidth and noise.
No solution is completely satisfactory.

[richie00boy]

OK I see what you mean. It depends on if you think one extra op-amp is bad I guess.

[parsecaudio]

I agree with you richie,
if the main expectation is the power an additional op amp is not a problem,but if the main goal of this circuit is a total symmetry,we could discuss of to the infinite.
One of the best solutions,at my advice,is the '80 SANSUI balanced amplifiers.......

[AndrewT]

Hi,
how are the two 15inch drivers connected?
What impedance are they?

[ostie01]

Hi, thanks for those great replies. Actually, it's for 2 Eminence Omega pro 15 in. (8 Ohm). What I think is (I'm not an expert), Since it is crossedover at 120Hz, distortion is not a great factor, I also think that passive crossover would give me as much distortion as bridging my amp. I'm not a Diana Krall guy, I'm more rock and roll so I rather like an amp that could have a little bit of distortion instead an amp that always go in clipping zone. Maybe I'm totally wrong with my concept, like I said, I'm not an expert. I don't know what is more important, an amp with a lot of headroom and power or an amp with a little less distortion.


Thanks to let me know.

[AndrewT]

Hi,
with 8ohm drivers and all that choice of two channel amplfiers, the answer seems obvious.

Use one channel dedicated to each driver. Take the mono signal from the crossover and parallel it into both amplfier inputs.

Don't bridge at all.

DEFINITELY DO NOT BRIDGE into 4ohms.

[richie00boy]

Yes either that, or series both drive units to get 16 ohms, then bridge the amp. That will gain you marginally higher output if you are being pedantic about numbers, marginally lower distortion, and nicer loading of your power supply. There really won't be much in it though.