Review on 🎶 Nobsound MS-10D MKIII HiFi Bluetooth Tube Power Amplifier Stereo Subwoofer Amp USB/Optical/Coaxial by Giovanni Glenn

The Nobsound MS-10D is NOT a "real" tube amp. As the previous reviewer wrote, this is actually a 60W per channel class AB solid state amplifier (using two Fairchild TIP41C transistors and two TIP42C transistors) with a tube buffer stage. A tube buffer, also known as a voltage follower or cathode follower, is a passive preamplifier in which the high output impedance of a source (e.g. a CD player) is reduced enough that it can be properly transferred to a lower input impedance load. Concerned about tube availability, this amp uses two 6N1 tubes and two 6P15 tubes (6P1 for the US version) which are very easy to find and inexpensive. I strongly recommend replacing the standard Chinese Shuguang/Beijing lamps with Russian or Bulgarian lamps of the same series. One of the owners (Stephen Smith) successfully replaced the stock 6N1 with a Telefunken ECC85 and the stock 6P1 with a Russian 6N1N-EB. Even with the built-in floor lamps, I was pleasantly surprised by the good sound. Despite being a solid state amp, the tube buffer gives the sound a "tube quality" that adds volume and smoothness to the sound. After replacing the standard Chinese lamps with Russian ones, the sound is especially high, and medium became softer and warmer. Low frequencies are more authoritative and fuller. The overall sound is very balanced. The stock Chinese tubes sounded etched and a little sparse for my taste (I think some people like that sound). The soundstage goes beyond my speakers. The picture is three-dimensional, three-dimensional and accurate. There is "air" on covers with Chinese pipes, but this "air" disappeared after I replaced them with Russian ones. It suits me as long as the music soothes my ears. For those of you using headphones this amp will have no problem with my AKG K270 and Sennheiser HD650. Of the two, I prefer the AKG-Nobsound combo. What I don't like about this amp is the flexible but thin and fairly short power cord. If only it had an IEC connector instead (so I could use an "audiophile" power cord). Bottom line, the MS-10D offers great sound at a great price. If you can live with the fact that this is a solid state tube buffered amp then you are sure to love it. ----- CONTINUED 1: Nobsound just released the MS-10D Mark II with built-in Bluetooth connectivity and USB 2.0 input for a premium of about $50. Check it out here: Nobsound® MS-10D MKII Hybird Tube Amplifier with Bluetooth/USB/Headphones for Hi-Fi ----- CONTINUED 2: I noticed that there are two versions of the Nobsound MS-10D (not Mark II) now available on the market: - Version 1 has a tiny blue LED ABOVE the power button - Version 2 has an orange/amber light AROUND the power button. I disassembled both versions and found their schematics. differ significantly. Both use the same Fairchild TIP42C transistor chipset. Version 2 delivers a lower voltage to the lamps (6.3 volts versus 8.5 volts) so from a technical point of view the lamps last longer. In addition, version 2 has better DC power control. Both sound similar, except I have to turn the volume knob to the 10 o'clock position for version 2 to get the same volume at the 8 o'clock position for version 1. Version 2's volume meter is less active as well. ------ NEXT PROMOTION 3: I have a chance to get the Mistral MM-1 Booster. Although both Nobsound and Mistral look "almost" the same (the latter has a darker gold faceplate), their inner workings are quite different. Mistral uses two Texas Instruments LM1875 chipsets (30W power) and Nobsound uses four Fairchild TIP-42C chipsets (65W power). Circuit diagrams are also different. In short, the Nobsound has slightly better circuitry than the Mistral. In terms of sound, I find Nobsound cleaner and more dynamic. Mistral is more musical. In terms of processing quality, both amplifiers are on the same level. Nobsound (version 2) is more difficult to parse. ------ FOLLOW-UP 4: Over the weekend I replaced the Nobsound MS-10D version 1 10 kΩ potentiometer with a 50 kΩ potentiometer to match the volume of version 2. . It works! So I've come to the conclusion that the volume problem in version 1 is due to using a lower resistance potentiometer. ----- FOLLOW-UP 5: My friend brought me his Nobsound MS-10D amp for a "partial" modification. What I did: 1. Replaced both tank caps with Panasonic FR 6300 uF 35v.2. All critical signal points resoldered with Cardas3 quad eutectic silver solder. All jumpers replaced with 24 or 18 AWG4 pure silver wires. Both Chinese standard 6H1 tubes replaced by Russian 6X1n tubes (his idea) Results: - Better expansion of the highs (extremely noticeable) - Mids are retracted. Not as full as 6N1 tubes - Cleaner and tighter bass - More transparent and open sound - Wider soundstage - Quieter, darker background Conclusion: My friend is very happy with the mod. However, I prefer the fuller and shinier mids of the 6N1 tubes. ----- CONTINUED 6: The power switch on one of my Nobsound amplifiers recently broke. It couldn't "click" properly. As a result, he could not hold himself in the "ON" position. To share with other Nobsound MS-10D owners, the switch is called "KDC-A10-10B AC 250V 10A SPST Push Button Power Switch". Do not worry. Although it says "250V" it will also work on 120V. Soldering is required. You may want to replace the shrink tubing at the same time. ----- FOLLOW-UP 7: Just got back from a friend's "man cave". All day my friends and I (four of us) compared the standard Nobsound MS-10D, Rotel RA-02 ($500) and Gryphon Atilla 2 ($11,000). All 3 built-in amplifiers. I'm very happy to report that Nobsound has done an excellent job with two serious competitors. Nobsound shines in the mids and highs. Of course, the 11-page Gryphon is the clear winner, but Nobsound isn't far behind. Rotel is a love and hate booster. He worked well in one genre of music but poorly in another. My friends were shocked that such a cheap amp could sound so good. Side walls in piano lacquer look. ----- CONTINUED 9: Some of you may have noticed that I changed my review from a hybrid amp to a solid state tube buffered amp. I sent the Nobsound MS-10D to a friend (who is a tube amp designer and enthusiast) to have a look and he concluded that 4 tubes are used as a buffer since there is no voltage gain. ----- CONTINUE 10 : Nobsound will soon release its latest DX-925 80W Class AB Hybrid Integrated Amplifier. Expect it to cost between $250 and $300. -----