Amplifier Chip Options

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Since I'm on a tight budget, I wonder what is a better option?

I"ll be driving two speakers rated at 6 Ohms.


(a) 2 pairs of LM1875 ( For stereo + biamp )
(b) 1 pair of LM3875 ( For stereo, NO biamping )
(c) 1 pair of LM4766 ( Stereo chip + biamp )
(d) 1 chip LM4780 ( Stereo chip, NO biamping )
That's still not very meaningful. Since you make no mention of how you plan to construct this I'll assume you won'r be buying a ready made PCB or kit but plan to make it on perfboard or point-to-point. Assuming this, I would suggest a pair of LM3886 as the way to go.
If you are on a tight budget I would agree to get two lm3886 chips.

I personally think that using vero/strip board is easier when it comes to the wiring.

there are many NC pins and although it might be frowned upon by others ,but I bent my pins so that a NC pin and a used pin go into one copper line of the strip board , that makes soldering easy.

Just make sure to fill up the tracks with solder for some of higher current tracks. And solder close to the chip pins.

But point to point wiring might be just as easier for some.

Get one toroidal 200va 22 0 22V

Use a bridge rectifier package (or two for a slightly better powersupply)

put 220uF and 100nF decoupling caps close to chip

And more capacitance (4700 to 10000) per voltage rail close to rectifier diodes.

Stick to the simple national application circuit.

That's my opinion.
I use 4 lm3875 chips in a biamp arrangement, all connected to a single power supply.

I started with 2 and then built up to 4. I would recommend this option (you didn't list it, but cost wise we are talking not much more than 2 pairs of lm1875)

I noticed quite a pleasant improvement going from 2 to 4 chips.

I just bought 10 lm3886 chips for a future project where I will be driving all 10 speakers in my mission 753's seperately. I think that with the low cost to build a chip amp, bi-tri-quad-quint-amping is a no brainer method of achieving stunning results.

I built my amp stages point to point. For a lm1875/3875 this is pretty easy to do, slightly more complex for the 3886 but it doesn't look impossible.

Good luck on your endeavour

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