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Several years ago, National Semiconductor came out with some very high performance, easy to use audio power LM3886 amplifier ICs. I was in need of an extra amplifier so I could biamp some of my home-built electrostatic loudspeakers so I tried the LM3886 chip. LM3886 amplifier was chosen because of the ease of use, power output, turn-on and off thump suppression, low distortion, and built-in protection against shorts and thermal runaway. There isn't much more to ask of a power amp than that. When driving electrostatic speakers, you can't have too much protection.

Several years ago, National Semiconductor came up with some very high performance, easy to use audio power amplifier LM3886 circuits. I needed an extra amp so I can bi-amp some of my homemade electrostatic speakers so I tried the LM3886 chip. LM3886 amplifier was chosen because of ease of use, performance, low distortion and a built-in protection against short circuits and thermal instability. There is not much to remove a power amp, than asking. When driving electrostatic speakers, you can not be much protection. There are people who have “golden ears” and the feeling, provided that no application note scheme is never good enough for it to “Optimize” to “improvements” to make a claim. The problem is that most of them do not engineers and have no idea what the possible consequences of their “improvements” can be. For example, for a few years if these chips were popular with the audiophile crowd, it was all the rage at minimum power filter caps for “Best Sound” to use. We are talking about 500 uF on each power rail for each chip used LM3886 amplifier. This is clearly insufficient and leads to a distortion in the volume low enough that the power supply sags under load. The problem was that some of the golden ears of the large power supply rejection IC spec saw and thought it meant that the chip could tolerate the 10V power supply ripple. The pendulum has swung the other way, and now many music lovers are sufficient amounts of energy storage in the diet.

In this application, we are building a gaincard like amplifier. This application type is named gainclone in audio world. To take a satisfactory audio response, we are adding a Linkwitz equaliser to the feedback line and adding bass compensation also. We are using LM3886 which is the revised version of its brother LM3875. These are the parameters that we are intereted in. Honestly this values are much more better than many of HI-FI amplifiers sold in the market. Especially it is hard to find 110dB signal to noise ratio. And another property is, when there is no input, this amplifier is quite like a dead. It is nearly impossible to hear any noise when you stick your ear to the speakers.

This is a monoblock Gainclone amp based on a LM3886 IC which is more suited to 4 ohm loads. It will output 70 Watts into 4 ohms. This version also uses a very high capacitance PSU and a snubber. The case is made entirely out of recycled aluminum bought from scrap metal yards.

This is a simple chassis using just 4 aluminum panels and 2 heatsinks. Designed around dimensions to tightly pack in a LM3886 chip amp kit. The top and bottom panels sit in ridges cut into the heatsinks with a table saw, and then the front and back panels just bolt into the end fins. Rear panel fixings are held with M3 nut and bolts, and panels that join to the heatsinks are held by M4 bolts tapped directly into the heatsinks so no additional brackets are required. Heatsinks are 75 x 160 x 50mm with a 10mm thick base.

Here's a 2x60W LM4780 Power Amplifier. LM3886 is very interested in our project was the first project, and were acclaimed. But the feedback we receive from you, from scratch, we knew we should make a complete device. One reason for that, but hard to find and the LM3886 integrated into the original cost of a fact to be taken into consideration. In this project, in which hosts two LM3886 LM4780 integrated with Integration, ie, making a complete amplifier. Advantageous LM4780 is an integrated, cost of both purchase price aşacağından sahtesinin made ​​of forged-not-at least we do not see, but also would have received only two LM3886 price, or even more cheaply. We mean the complete amplifier, pre-amplifier, power amplifier and power supply hosts, ready for use, kutulayıp living room you can put the head in a corner of the device. If your hand if you have preamps or power amplifier, may be helpful in other projects.

LM4780 gainclone amplifier with a design similar to the National Semiconductor BPA-200 (Bridge/Parallel Amplifier) which uses 4x LM3886 per channel and an input buffer. The total effect is (2x LM3886's paralleled amplifiers) 2x Bridged and should give approx 225 watts into 8 ohm and 335 watts into 4 ohm speakers when used with a sufficient power supply.

Having decided to build an ultra-compact design, using a spare LM4780 seemed like an obvious plan. Having said that, I might choose a different IC if I didn't already have one to hand. The LM4780 contains two LM3886 dies (reference) giving 60 watts per channel, which is rather more than required this application. National Semiconductor make an enormous range of IC's with differing power levels and configurations, and there are plenty of possible candidates for this application - after all, we only need a few watts as this amplifier will principally be driving small speakers on the computer desk.

Having decided to build an ultra-compact design, using a spare LM4780 seemed like an obvious plan. Having said that, I might choose a different IC if I didn't already have one to hand. The LM4780 contains two LM3886 dies (reference) giving 60 watts per channel, which is rather more than required this application. National Semiconductor make an enormous range of IC's with differing power levels and configurations, and there are plenty of possible candidates for this application - after all, we only need a few watts as this amplifier will principally be driving small speakers on the computer desk.

Something you should use in any amplifier, especially in discrete amplifiers, is loudspeaker protection. The first part is the DC detector. This circuit will trigger the Off output if DC is present on the audio lines. The input goes through a low pass filter and then through the diodes. If there's any DC on the lines it will turn on the two transistors who will then turn on Q3, which triggers the Off signal.