Talking about the combination of integrated operational amplifier and integrated amplifier

Successive operational amplifiers and integrated amplifiers are two types of devices that novice and student enthusiasts like to use. They have many varieties, different performances, and their sound quality and tone. How to match and combine the above two types of devices in order to make the best use of them, give full play to their respective advantages, and create a good performance-price ratio, is a question worthy of discussion.

　　 Although the author has accumulated some experience during his fever in the past few years, he has also stocked a considerable number of audio devices. Among them, there are many integrated op amps and integrated amplifiers, including the early fever op amps LM833N, NE5532N, NE5535N and the recent popular OP275G, LT1057, AD827JN. Integrated amplifiers are some well-known models, such as TDA1514A, LM1875T, LM1876TF, LM3886TF and the early TA2030A. Of course, integrated blocks of models such as JRC4558P, TL072 and TDA2030, because their performance is not yet "fever" level, there is no need to study them.

　　 The above-mentioned integrated amplifiers are all finished boards. The components and craftsmanship on the boards are quite elegant and simple. As for the above-mentioned op amps, since they are all standard dual op amps, only one pre-buffer amplifier board is used, which is the one used by AD827 in "Xiaopin 1876" in "Electronic News" on June 13, 1999. . The components are very sophisticated: DALE W gold film resistors, WIMA, ELNA capacitors, APLS potentiometers, silver-plated double panels, and the craftsmanship is also very sophisticated. The author removed the AD827 and replaced it with a 24K gold-plated op amp socket.

　　 As for the power supply, the operational amplifier uses a servo power supply ±15V power supply, and the power amplifier uses the power supply mode of large ring bull, double bridge rectifier, large pond and small pond electrolysis.

　　 The author also invited several like-minded fans to comment together. The listening time is still selected after seven o'clock in the evening, the purpose is to have a better environment. The equipment used is the third-generation DVD8058A of Xiamen New and Hivi Duchy 2.1C, and the software is familiar with saxophone, Tsai Chin’s old songs, Hugo Ⅰ and so on.

　　 I love 1876, let it take the lead, and replace it with the aforementioned six op amps in turn. Of course, the combination of 827+1876 that the author used before has a good listening experience and has won unanimous praise. This matched mid-to-high frequency has a strong musical taste, smooth, balanced, natural, and warm, which makes people intoxicated. The low frequency is also clean and tidy, and it can be retracted freely. The combination of OP275+1876 is slightly inferior in the high frequency extension, the low frequency is slightly blurred, and the intermediate frequency is still excellent. The overall feeling is slightly lower than that of the AD827, which is the first choice for the pursuit of cost-effectiveness. Although LT1057 is famous, it is not suitable for matching with 1876. The problem lies in the timbre, which always gives people a "cold" and "thin" feeling. LM833 is similar to NE5532, with warm tone, but strong high-frequency burr, and low-frequency can't stop the tail. The noise of 5532 is slightly louder. As for the NE5535, one channel was severely distorted after being replaced, and it was estimated to be damaged, so the comparison was withdrawn. In summary, for the LM1876 power amplifier, AD827 can achieve high performance, while OP275 has a high cost performance.

　　 Next, we replaced the LM3886, and felt that it was very similar to 1876, and it was more powerful. It still feels better with AD827. OP275, NE5532, and LM833 have little difference after use, but OP275 has better low frequency, which may be related to its 22V/ms conversion rate. The LT1057 still embodies the characteristics of heavy metal flavor. This combination makes people feel that it is good for home theater, dynamic and full of momentum. Especially the [Kiev Gate] section of the "Picture Exhibition" in "Hugo I" is very magnificent.

In the prestigious LM1875 power amplifier, AD827 is not very prominent, LT1057 is shocking, the overall balance, the sound is moderate, the high and low frequencies are rich, the music details are also handled properly, especially in Kenny·G Sachs "Spring Breeze" The triangle iron accompaniment of the background music is particularly clear and pleasant, with subtle details. NE5532 and OP275 are also good with 1875. Especially 5532, it can be described as cheap and good quality, it has the same conversion rate as 1875, there is no speed "bottleneck" problem, it is worth recommending, LM833 is slightly worse.

　　 As for the 1514A, because it is a "cold" type power amplifier, it is difficult to get along with the LT1057. The AD827 and OP275 are better in the other op amps. NE5532 and LM833 can also be matched with it, but the intermediate frequency is always unsatisfactory. Comprehensive consideration, 1514A, OP275 can be the first choice, although not very prominent, it is quite satisfactory.

　　The TDA2030A that was unveiled, although it is a yellow flower yesterday, it has a large amount in the society, and quite a number of computer active speakers still use it. Our suggestions can be used as a reference for 2030A users. We recommend using NE5532 or LM833, they are enough with 2030A, there is no need to pursue the other three. From the sense of hearing, the difference is minimal.