Be wary of six power amplifiers to fake
The rise of home theaters in recent years has led to a sharp increase in the production of domestic amplifiers. There are a number of fine products among the domestic brands of many brands. But there are also a lot of inferior amplifiers that are 'spoofing.' The following introduces some fake methods and the author's identification methods, I hope it will be helpful for everyone to choose the power amplifier. The rise of home theaters in recent years has led to a sharp increase in the production of domestic amplifiers. There are a number of fine products among the domestic brands of many brands. But there are also a lot of inferior amplifiers that are 'spoofing.' The following introduces some fake methods and the identification methods that the author has found out. I hope it will be helpful for everyone to choose an amplifier. 1. Aiming at the idea that many people think that the power amplifier 'sinks better,' low-quality power amplifiers use ring transformers, and many use fever double-ring cattle. However, the quality of this type of silicon steel sheet is very poor, and the winding process is not enough. This results in low efficiency and low actual power, especially in quiet times, it is easy to hear ring cows humming. 2. Charge imported brand-name capacitors with large-capacity domestic capacitors. Some manufacturers even use the backlog of early capacitors to repack and recharge new capacitors. The actual withstand voltage and capacity of these capacitors simply do not reach the nominal value. These capacitors are generally lighter than genuine ones. 3. Charge low-end 4558 or 082 to mid-to-high-end op amps such as 5532. Many so-called 5532s are actually polished from 4558. There are also domestic-made power amplifier tubes to charge imported tubes, especially Toshiba tubes with the most fakes. 4. Poor quality amplifiers often have 5- or even 7-channel outputs. But in fact, the surround and center channels of many power amplifiers come from the left and right main channels in series with resistors. Although some power amplifiers have independent amplifier circuits, they only undergo simple delay processing. There is no dedicated decoding circuit or sound field processing circuit at all. When identifying such amplifiers, if you find that the surround and center channels cannot be individually adjusted in volume, it must be a false surround from the main channel in series with a resistor. If it is nominally equipped with Dolby directional logic decoding without noise testing. Or the surround speakers also sound when only a mono signal is input, then the amplifier is a pseudo surround sound amplifier. For power amplifiers using technologies such as SRS and Q-Sound, the true and false can also be identified by comparing the listening function to turn on and off the surround function and selecting different surround modes. It should also be reminded that although some audio manufacturers have actually adopted Dolby decoding chips such as M69032, they have not passed the Dolby certification and are also affixed with the Dolby logo. Such power amplifiers cannot guarantee the necessary performance indicators such as channel separation, and are also among the counterfeit. 5. Lack of complete protection functions. Although the inferior machines have the function of anti-shock protection, most of them have omitted the necessary over-current, over-voltage and output DC protection functions. As a result, the reliability of the whole machine is poor, and if there is a problem, it is likely to burn out the expensive speaker unit. For the identification of such fake methods, the first is to determine whether the design has a complete protection function by looking at the circuit diagram. The second is short-circuiting the output for a short time, if the power amplifier does not appear to protect. It is likely that these protection circuits are omitted, or at least it is poorly adjusted. 6. Class B charging and class A, one-sided pursuit of multi-function and appearance, neglecting the level of circuit design, and using this as a selling point. This all belongs to the 'advanced' trick. For these 'characteristic' amplifiers, if consumers are not very familiar with audio equipment, it is best to ask a knowledgeable person to help select them, and try to choose the products of major audio manufacturers as reliable as possible. Finally, I would like to make three suggestions to friends who are going to buy amplifiers. The first is to adhere to the principle of 'enough and easy to use', and don't pursue too much function and appearance. For Hi-Fi enthusiasts, a two thousand yuan AV amplifier may not be as good as a two thousand yuan two-channel amplifier. The second is to remember to match the power amplifier and the speaker reasonably. The third is to meet your own ears as a principle. Don't be blinded by the sound of “crashes” specially prepared by the dealer. Bring a few high-quality CD test machines that you are familiar with may benefit you a lot.