Chip Amp for bass only

[madman]

Hi There,
What would be the best chip to use for bass only (200Hz down).
Maybe any of you GC-wizzards have a scematic for me.
I beleive one should use a good, big power supply. Any ideas ?
Morten

[BillW]

I have a similar question. I am considering using a 2-channel BrianGT gainclone for driving a Tempest subwoofer in a large sealed box. I was thinking driving each of the 8 ohm dual voice coils with one of the gainclone channels.

Is this a suitable amp for this subwoofer project? Are there design mods or component changes which may make the amp better for low frequencies only? I suspect that the BG upgrades would be a waste of money.

Thanks in advance for your ideas.

Bill

[S.C]

I am also considering to make a 2.1. Will BridgeClone do the trick?

[BrianGT]

I am going to experiment with building a BridgeClone, bridged with 3 parallel chips on each side, meaning 6 amplifier boards per channel. This should provide about 300W into a 4 ohm load, assuming that you have adequate heatsinking and transformer.

I should get around this in a couple of weeks, and will post details. I might even provide a kit with multiple boards and matched resistors in the future if it all works out. (in addition to a front interface board with a balanced converter)

Bridgeclone thread:
Bridgeclone

--
Brian

[JDeV]

I recently build this amp (200W bridged/parallel - http://www.national.com/appinfo/audi...ation_Note.pdf or http://www.national.com/an/AN/AN-1192.pdf) using the LM4780 (stereo 56W chip) - look here for breadboard pics and circuit - http://www.diyaudio.com/forums/showt...711#post286711
and this for a controler http://www.diyaudio.com/forums/showt...050#post336050

For sub application, it works very well. Just waiting for my Dayton DVC 12" from PartsXpress. Was going to use Adire Shiva but decided against it after really terrible service from Adire.

200W circuit:

[soundNERD]

how bout the lm4651/4652 combo? thats designed for a sub.

[macboy]

how bout the lm4651/4652 combo? thats designed for a sub

That's a class-D amp, which is definitely not what we lovingly refer to as a "chipamp". Chipamps are basically power opamps, which makes them extremely easy to use. This class D amp is much more difficult (and expensive) to build due to a large number of external components including a complicated output filter.

[soundNERD]

not that one... and its got high power and low heat. whats better in a sub? since there is no chipamp designed for subs, thats the only choice.

but the 3886 actually works pretty well with a sub, and i don't know what the people here are talking about when they say the 3886 can't drive 2 ohm loads. IT CAN. Sorry, a little off topic there.


-Mike

[MWP]

Originally posted by soundNERD
but the 3886 actually works pretty well with a sub, and i don't know what the people here are talking about when they say the 3886 can't drive 2 ohm loads. IT CAN. Sorry, a little off topic there.

No.. they are right, one LM3886 cant.
The current overload protection will kick in and clip the signal.

But, 3 paralleled LM3886's would drive a 2ohm load no problems.

[soundNERD]

well, with my experiences, it can, just runs hotter.

anyway, speaking of paralling a 3886, how is it done? I have two of the same amps using a 3886 with the same power supply and the inputs tied together. I connected the output of one amp to the speaker, then plugged it in. I touched the second amp's output to the speaker input (where the first amp's output was connected to) and it sparked. What did I do wrong? Speaker is an 8ohm.

I know there is nothing wrong with either amp, since i tried them with two seperate speakers.

And how do I take two seperate amps and run them in bridged mode? Is there a way to do it without modifying parts on the board?

Thanks!
-Mike