Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
His stereo costs him only about $70.00 but it sounds fantastic. He is a salesman. He makes a good demo and knows how to sucker people out of their money.
His stereo costs him only about $70.00 but it sounds fantastic. He is a salesman. He makes a good demo and knows how to sucker people out of their money.
Bwa-ha-ha...thought you were gonna tell me something. Hey? You think he will sell some stuff for me? I got an old RadioShack Stereo. But he did make it right? I need to meet this guy Maybe you and I can make some stuff for him to sell.
The datasheet for the LM3886 chip amplifier shows that its distortion at 1kHz, 60W into 8 ohms is only 0.002%.
It costs only $7.30US at Digikey today and they have nearly 500 in stock.
The datasheet for the LM3886 chip amplifier shows that its distortion at 1kHz, 60W into 8 ohms is only 0.002%.
It costs only $7.30US at Digikey today and they have nearly 500 in stock.
Yes it is a very impressive chip, I got one in pounds, it was £4.30 and no shortage of supply. I will go back to it and try to get it working when I have some spare time. I will also buy a device that contains one, take it apart and see what I can learn.
Can someone give me a simple explanation of the term "feedback"?
I've got an "HLLY TAMP-90", another amp based on a highly rated chip - this time from Tripath, and class-D.
I got it free, brand new, because it's duff - an old acquaintance ordered it off Ebay from Hong Kong, and it didn't work when it arrived. I had a quick look at it for him, and there was nothing obvious (and I wasn't interested in getting deeply involved). Anyway, he told me to dispose of it - and it's still sat here in it's cardboard box.
Tripath went bankrupt 3 years ago. I guess their "class-T" amplifier chips did not perform very well. There are many amplifiers using the Tripath chips sold on E-Bay and made in Hong Kong.
The old CA3080 has a very high output impedance and a very low max output current so its output class of operation doesn't matter.
The CA3160 is one of the first Cmos opamps and its output is class-A with a heavy idle current when its supply voltage is high.
Well, I wasn't saying they were lying or anything...lol. It's just sort of hard to believe especially at that power level. I did notice it was about 90% of maximum. Bet it drops off rather quickly after that. Still your talking over 100 watts between the two at .002% distortion. I would like to hear one.
Yes it is a very impressive chip, I got one in pounds, it was £4.30 and no shortage of supply. I will go back to it and try to get it working when I have some spare time. I will also buy a device that contains one, take it apart and see what I can learn.
Can someone give me a simple explanation of the term "feedback"?
Yeah, feedback means pretty much as it sounds. It means you have a portion or all of the output from an amplifier (mainly), being fed back to the input somewhere. There are two types of feedback. One is negative feedback and the other is positive. Both are useful and are applied in many circumstances. Let's take an Oscillator for instance. An oscillator will always have positive feedback so that the output is aiding the input or vice-versa. So an oscillator is essentially nothing more than an amplifier with positive feedback. Positive feedback itself is an in phase signal or zero degrees phase shift whereas negative feedback is 180 degrees out of phase.
Negative feedback will have application in situations where say you have a very powerful radio frequency transistor amplifier stage and maybe the transistor itself has a very high gain. Being that radio frequency travels through air as well as through wire or printed circuit board traces, the path through the air can very easily find a portion of it's output signal circulating back into the input thereby causing undesired feedback or oscillation. This could come from the antenna itself after the signal has been phase shifted again through an output transformer and some sort of LC (inductive and capacitive) network and may be in phase or close enough to where it is aiding or adding to the input. It can also find its way back through standing waves or strip-line (transmission line effects) and various other forms of VooDoo as is common with rf. In most cases the radio frequency (rf) amplifier will be a common emitter configuration and so the output from the collector will already be shifted 180 degrees. By using a small value of capacitance to couple this out of phase signal back into the base input we create some negative feedback. This technique is known as neutralization and essentially what it does is reduce some of the gain of the transistor so that it will be less prone to feedback.
Yeah, feedback means pretty much as it sounds. It means you have a portion or all of the output from an amplifier (mainly), being fed back to the input.
Yes that makes sense now. I have a piezo circuit which has a 2N transistor, some of the output is fed back to the input. Thanks!
I did just buy the gadget below. It is an ultrasonic stain remover, so it uses frequencies above the audio range, I think this one uses 100KHz (yet to be confirmed). I mention it because it contains an LM3886. I'm going to take it apart and study the circuit. That will be fun. What's not fun is the price I had to pay...they are only available in the US but I'm in the UK. So the gadget cost $20 but the shipping was $40!
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Maybe you and I can make some stuff for him to sell.
