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djdan 14th September 2002 07:11 PM

Many smaller amplifiers vs. bigger amplifiers.
I want to make an high-end amplifier for my home theater system and I have a dilema. I ask your opinions about this:

I have 4 bass speakers (Visaton 12 inch/ 150w rms/8ohm ) for subbass loudspeaker, all speakers working for mono subbass channel .

I have 4 amplifiers module 150w/ 8ohm and 2 amplifiers module 300w/4ohm , all module at same quality .

What is the best option ?
1. Every speaker driven by a module 150w/8ohm , or
2. Two pair of speakers in parallel driven by two module at 300w/4ohms.

The costs are not important . I want to know your opinion or experience about sound quality ( generaly speaking ).

Any coments or sugestions , please .


Peter Daniel 14th September 2002 08:17 PM

How much power 150W modules give at 4ohm?

I would tend to power ea. speaker with a separate module.

djdan 14th September 2002 09:36 PM

260W rms / 4 ohms with 0.03% THD .

Power supply for a single module is 450VA toroidal transformer with 2 x 4 x 4700uF/80V and 35A bridge rectifier. This configuration was used just for measurement.

But if I will choose 4 x 150W/8ohms I will make a power supply with one toroidal transformer 1200VA .

skaara 14th September 2002 09:51 PM

I suggest that you more powerful transformer, or even better, transformer for each channel..

thylantyr 16th September 2002 03:15 PM

This is what I like if money and space is no object.

One amplifier bridged per speaker
(I like bridged so I can utilize both rails for headroom)


One amplifier bridged per crossover point.

I was using multiple small 200w mono amps with +40v/-40v rails.

But, I'd like to take this to the next level someday and go
for +100/-100 rails - heheh

djdan 16th September 2002 07:11 PM

In fact , the 150w / 8 ohms module is in bridge mode for the high value slew rate ( volts/uS and ampers/uS ).

But for me it isn't very clear , yet , what combination will be best and why.

I saw and read many article about that but I didn't saw something clear.

Orgonom 16th September 2002 07:23 PM

Hi djdan,
i would take 4 Amps and single supply, invert signal for two of them (speaker cable invert also of course).
So you load the pos/neg supply equally.
Why 4 Amps ? - They should control 8 Ohm easier then 4 Ohm.

Nelson Pass 16th September 2002 11:02 PM

This might not solve your problem, but I believe that
the best approach is multi-amping, in which each driver
gets its own amplifier and filtering is done before the

Lowest distortion, highest output approach.

Also, maximal tweak-ability.


planet10 17th September 2002 12:19 AM


Originally posted by Nelson Pass
but I believe that the best approach is multi-amping, in which each driver
gets its own amplifier and filtering is done before the
I concur 100%. My system, if ever finished :D , with have 6 valve amps (monoblocs) and 8 SS amps (the last to drive 4 woofers and each coil on dual VC subs).


djdan 17th September 2002 04:40 PM

Thank you very much for your reply .

Yes , every speaker driven by an amplifier is my choise , too.
More headroom , more reliability and many other good things.

I will put 8 capacitors and bridge rectifier to every module PCB ,
(2 x 18800uF) and 24dB/oct active low-pass filter [ 80Hz ].

Best regards !

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