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Post by paintedklown on Jun 9, 2012 10:28:03 GMT -5
Nope, you're right on. OAs model the perfect amplifier, high input impedance, low output impedance. Generally with 2 inputs +/- and 1 output. They come in single, dual and quad packages with 1x 2x and 4x amplifiers in one IC. You can build amps, buffers, filters......with them.  Thanks for the input. So, is this what amplifiers are made of? I always thought they were a series of step up transformers and capacitors. LOL! I thought the difference between "good" amplifiers and "crappy" amplifiers were how many "steps" were used in the design of the amplifier. For example, lets take two amplifiers rated at 100w into 8 ohms.: A "crappy" amplifier would have (and I am pulling numbers out of my hat here) five step up transformers and small, low grade capacitors, while "good" amplifiers would have ten step up transformers and larger, better grade, capacitors. This is (of course) an oversimplification and ignores the power supply and all that jazz (lets pretend they are equal for this example), but I was told this by a buddy in high school who maybe didn't know what he was talking about. 17 years later...I still believe what he said.  ;D EDIT: I think I may have answered my own question (with the help of wikipedia) en.wikipedia.org/wiki/Electronic_amplifierI should really take some classes regarding electronics design. I am completely fascinated about this kind of stuff, but sometimes reading even the wikipedia pages is over my head. Perhaps I should just read slower and repeatedly.  ;D |
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Post by Chuck Elliot on Jun 9, 2012 11:28:56 GMT -5
Forget transformers and capacitors. A perfect amp will have neither.
Each amplifier stage will be designed with a gain in mind. This gain may be 0 if used as a buffer. As you increase the gain of a stage the distortion may increase.
Since op amp generally are limited to +/- 15V which means that the output will be something below 15V peak-Peak. Therefore a power amp that has rail voltages much higher, say 100V pp, to drive the speakers, will use discrete transistors or FETs in the last stages of amplification.
The measure of a better amp is in its design and the quality of the components used, not the number of stages.
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Post by paintedklown on Jun 9, 2012 11:36:49 GMT -5
Forget transformers and capacitors. A perfect amp will have neither. Each amplifier stage will be designed with a gain in mind. This gain may be 0 if used as a buffer. As you increase the gain of a stage the distortion may increase. Since op amp generally are limited to +/- 15V which means that the output will be something below 15V peak-Peak. Therefore a power amp that has rail voltages much higher, say 100V pp, to drive the speakers, will use discrete transistors or FETs in the last stages of amplification. The measure of a better amp is in its design and the quality of the components used, not the number of stages. Interesting, and thanks for the education in electronics.   I am going to find some time to do some additional reading about (Emotivas) amplifiers (specifically) to see what I can learn about them with the information you provided. |
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Post by bobbyt on Jun 9, 2012 19:36:06 GMT -5
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Post by sparky14 on May 11, 2022 16:49:50 GMT -5
Bumping up an old thread with a question....
Opamp Rolling Question - so I bought some OPA1656 so go into my Aiyima A07. However, it is apparently a SOIC chip mated to a DIP8 connector. OK fine. However it doesn't have a notch, so I don't know how to orient it into the DIP8 socket. However the pins are numbered. So, does the 1-8 side go with the notch, or does the 4-5 side go with the notch?
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Post by 405x5 on May 11, 2022 19:44:37 GMT -5
I shall demonstrate….  |
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Post by MusicHead on May 11, 2022 20:51:59 GMT -5
Bumping up an old thread with a question.... Opamp Rolling Question - so I bought some OPA1656 so go into my Aiyima A07. However, it is apparently a SOIC chip mated to a DIP8 connector. OK fine. However it doesn't have a notch, so I don't know how to orient it into the DIP8 socket. However the pins are numbered. So, does the 1-8 side go with the notch, or does the 4-5 side go with the notch? On an IC the notch (or a dimple or a dot) is always on the side where pin 1 is. |
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Post by sparky14 on May 12, 2022 8:57:52 GMT -5
Bumping up an old thread with a question.... Opamp Rolling Question - so I bought some OPA1656 so go into my Aiyima A07. However, it is apparently a SOIC chip mated to a DIP8 connector. OK fine. However it doesn't have a notch, so I don't know how to orient it into the DIP8 socket. However the pins are numbered. So, does the 1-8 side go with the notch, or does the 4-5 side go with the notch? On an IC the notch (or a dimple or a dot) is always on the side where pin 1 is. Perfect, thanks! |
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Post by 405x5 on May 12, 2022 9:30:48 GMT -5
Don't bother. If the XDA-1 isn't to your liking, buy a different DAC. All that you will accomplish by swapping out the opamps will be to void your warranty and make the unit difficult to sell on the 2nd-hand market. This advice is coming from a guy who sold the best hi-end gear back in the day and currently has a *killer* 5-channel tube/MOSFET power amp. There is no way in hell that I would start tube rolling on my amp. If BK Butler didn't get it right, how in the world am I supposed to do better than the guy who is world renowned for his unique designs and has the patents to prove it?? Spend your time and money getting the best speakers, room treatments, and source material that you can. *That* is where you will really be able to enjoy the fruits of your efforts and money... -RW- Ten years after the fact….. Truer words never spoken! 🙏 |
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;D
