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This shop promises: all speaker units in this shop are authentic, and friends who buy Qin Chao products will provide a one-week trial listening, and you can unconditionally refund if you are not satisfied（Due to the low profit of our shop, the buyer has to bear the cost of returning the goods）.The buyer is responsible for the cost of packaging.

Configuration: QM2018 hifi front level one

        Tianxian with 1 1.5m power cord（Optional American standard or national standard, leave a message）


Size   width 480mm   height 90mm  depth 320mm
Enter    2 RCA 1 balance（Switchable）
Output   2 way RCA 1 way balance  （Simultaneous output）

          There should be some old friends in the forum who have some understanding of my past. Before 2010, we had produced some HIFI preamplifiers using electronic tubes In recent years, almost all of our energy has been placed on multi-channel products. There are very few products on HIFI, and there is not a single HIFI preamp. In recent years, the calls for us to produce HIFI products have been increasing. , So we launched the YC2300 high-power HIFI power amplifier the year before last, and received very good praise from users and friends, but the HIFI preamp that can be matched with it has not come out for a long time. From the decision to do this preamp to now It has been two or three years. During these three years, we have been overthrown many times and we have hoped that it will be better and more comprehensive. We have also listened to the opinions and suggestions of many HIFI seniors. The first non-gut HIFI preamp is about to go on sale.

      Our goal is to make a preamp with neutral sound. The sound should not be biased. It must be long-lasting listening and it must have a good reproduction of the details of the music. It must be able to interpret large-scale music quite well, and it must be thick. Aunt Cai''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''s midrange, and of course the singing of Jacky Cheung who has to behave well

       After nearly 3 years of hard work, Qin Dynasty’s front-end QM2018 is finally finalized and produced. This front-end uses Maijingtu C48 as a rebound and then joins Qin. Come towards your own element.

       The whole machine uses 2 small Japanese Panasonic 30VA E cattle, each channel is completely independent power supply, Schottky ultra-fast recovery rectifier diode, German super fever filter capacitor , The ultra-stable voltage stabilizing circuit constitutes the power supply circuit of this machine. We do not use ordinary oxygen-free copper wires for the power supply wires but single-crystal copper silver-plated wires. These methods and materials are used for the front-end The sound laid a good foundation.

         Sometimes luck is really important. Everyone should know that cows affect the sound. In the second half of 2017, when I was choosing cows, I ordered the ring cow, E cow and R cow respectively. The result is not to my satisfaction. The ring cow''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''s voice is unpleasant and a bit dry. The E cow''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''s noise is a bit loud and the resolution seems to be weak. The R cow can scream, and the small R cow can scream. I am still not satisfied with the proofing, because I removed the cow of the Maijingtu C48 and compared it, and the gap is indeed obvious. Continue to communicate with the manufacturer. After the manufacturer learned that I was the sound of the cow with Maijingtu, they basically All the above said that they are not confident, because some things really cannot be explained by indicators. They also said that if it is noise, insufficient power and other problems, they can solve it. They really don’t know how to solve this, but there is a factory suggestion I dismantled Mai Jingtu''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''s cow for his reference, but I didn''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''t reply to him immediately, because if the cow was dismantled and then wound around, it might not be able to achieve the original level, then my front-end machine. . . , I don’t seem to be able to solve this problem without letting him demolish it. I have been contradictory. . . Unexpectedly, the second-hand parts seller in Shantou called me a few days later, saying that there was a batch of Panasonic cattle, which had been removed from the new machine. I immediately bought 20 prototypes and tested it back. I feel that this is the voice I want. , I bought all the thousands of small E cows back. I was laughing in my dreams. This luck is too good. Isn’t it God’s will?

        The amplifier circuit imitates the fully balanced amplifier circuit of Maijingtu C48, but makes a pair of RCA signal output. The main amplifier of the amplifier adopts the NE5534 of the United States ON, and the output buffer adopts the NE5532 of the United States ON. Some friends may be a little confused. Now There are many op amp models, and a lot of them have much higher performance than 5534/5532. Why use the outdated op amp king NE5534 and 5532?  

      I prefer the sound of C48. When I decided to learn this machine and open its case, I was a little suspicious of my eyes, the pre-amp signal amplification part It turned out to be the all-purpose ruby ??universal capacitor YXA series. Whether it is power decoupling or signal coupling, the only two American Sibi capacitors are power filters. The core parts of the amplification are also very ordinary SMD 5532 and 5534. I am very depressed, so ordinary How can the raw materials of the company be made to a level that people can hear and do not want to shut down? The audibility, dynamics, resolution, and background tranquility are all quite good.

      I think I’m going to make a big mistake, it should be able to easily surpass this original machine, and then we took a look at the schematic diagram of the analog enlarged part, The RCA part is buffer-balanced amplification-to single-ended-buffered output, and the balanced part is balanced input-to single-ended-buffer-balanced amplification-to single-ended-to balanced output. According to this framework, we re-drew the PCB. First, we bought the same capacitors as the original machine, 5534/5532 of the American Big S, and turned it on for audition. Why didn''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''t it feel like the original machine? It can be described as dry and astringent. My intuition tells me that there must be something wrong. I moved out a test instrument similar to AP and compared the distortion and curve with the original machine. There was not much difference between the distortion and the curve. How could there be such a big difference in the sense of hearing? What? Suddenly the idea may be related to the material of the PCB itself. I immediately contacted the PCB manufacturer and asked him to use 2OZ copper to make a sample. Haha, my intuition is quite accurate. Ohm’s law can’t be used to judge the sound. If the current is not large, there is no need for copper with low resistivity. I also know in my heart that it may be better if you change to a PCB with a purer copper, but there are some things that we can’t control.


        The thick copper PCB will sound thicker, but there is still a big gap with the original machine. Op amp related, so I purchased some advanced op amp samples with overwhelming indicators, the models are AD827, AD847, AD979, OPA2604, AD828, gold-sealed op amp AMP9980  OPA4458BM, N combination mix and match, test one by one , When I tested the combination of AD979 and AD827, it really made my eyes shine at first, so beautiful treble, so strong bass, but after listening for two more days, I still feel that it is not so perfect, and the human voice seems not so good. , Thinking that such a good and expensive op amp is definitely a good choice, and you should try to change those coupling capacitors and power supply capacitors, which is another round of capacitor battles. . .
  
       Ruby, Chemical, Nikon, Sibi, American Chemical, Philips, Siemens. . . This process omitted tens of thousands of words. . . . Finally, ERO''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''s main filter capacitor and chemical and ELNA audio dedicated capacitors are used for coupling. The sound with this combination is the most comprehensive, and some aspects may surpass the original machine. Next, the program was compared with the original machine. .       Compared with the original machine, this combination is a more modern sound, which means that it is not durable enough to listen to. The human voice is still a bit poor and the background is not clean enough. Where is it? Is the op amp too advanced? I removed the original SMD 5534/5532 and put it on to have a try. The human voice is actually more listenable, but I can’t figure out which company’s IC is because there is no LOGO on it. I worked hard to confirm that it was a product of ON in the United States, so the next step was to purchase ON’s 5534 and 5532. Although it was somewhat convergent to become a bit resistant to listening, I was still not satisfied, so I tried to make a fuss on the power supply. Add inductance filtering, replace all the connecting wires on the amplifier circuit with single crystal copper silver-plated wires, and replace the fuses withSterling silver fuse. . . . In this way, the sound is almost the same as what I wanted. The preamp that is analytical, durable, and dynamic is coming out.

       The sound produced by a machine is definitely not determined by a certain component. There are too many factors that determine the sound. Every change may affect a little bit. A combination of many little bits may be a big change. . The sound you like can only be known by trying more. It is not the so-called fever component that can produce the sound you like, and the pile of materials may not necessarily produce a good sound. . . 

      The veterans all say that HIFI is playing video games. This is a bit exaggerated, but it also makes sense, because if the equipment is of good quality, improving the power supply can indeed get better results. Recently, I also spent a lot of time on tossing HIFI. We bought several kinds of power cords and power sockets on the Internet, and compared them repeatedly. Finally, I chose the gold-plated copper power tailstock and Tianxian equipped with reference series power supplies. The OEM cleans up the inventory. The kind that becomes extinct when used up. It should be said that the price can be bought after many times. The plug tail of the power plug is also gold-plated copper. This power cord is definitely not the best. But it is definitely the most cost-effective.

About warranty and shipping cost:

  This product is guaranteed for free for 3 years. If it needs to be returned for warranty within 3 months, the seller shall bear the round-trip freight, but not the packaging materials and wooden racks returned. After 3 months-if the warranty needs to be returned within 1 year, the shipper will be responsible for the freight, and the buyer will be responsible for the return freight after one year. Free warranty within 3 years. After 3 years, the cost of repair parts will be charged. If you do not accept this agreement, it is recommended that you do not purchase this product

Entrance of Qin Chao Yicong Audio Forum:http://www.ycqin.com

Please pay attention to the receiving friends:
      When you receive the goods, you must first inspect the goods and make sure that the appearance is no problem before signing. If you have any appearance problems, please contact me in time at 13609428908 Mr. Qin. Or directly refuse to sign the return and contact customer service to reissue the goods. If there is any appearance damage after signing for the receipt, our store will not be responsible, thank you for knowing