BOYUURANGE A20 Hi-Fi Intergrated Amplifier KT88 Tube Single-end Class A 4ND VU Meter

I decided to purchase this amp after watching various YouTube audiophile channels about how great some of the Chinese tube amps are. I thought about the A10 which has been reviewed well, but I wanted something a little better. There is practically no information on this one. However, it is a little more powerful and uses (arguably) better kt88 tubes for more authoritative bass.. Anyway, this is a heavy, substantial piece of hardware, weighing in at about 42 pounds with nice goldish machined steel and mirrored chrome finishes. Once burned in the sound is smooth and lovely. I hooked up a switching system so I could easily A/B compare it with my Marantz integrated amp. If I could only have one it would be the Reisoing hands down. With my Klipsh rp5000's it's pretty much everything I hoped for. Sparkling holographic highs and reasonable, melodic bass. Now the Klipsh's are very high sensitivity, so your mileage may vary. 8 watts per channel tube is not like solid state. It comes off as similarly powerful to 40wpc solid state, very loud for my small room. I rolled in some Mullard remakes kt-88's and some RCA reds on the pre-tubes (see 3rd picture). I think there's a good chance that the tubes that came with it are pretty good after break in, I did not wait to see. I also replaced the rectifier tube with a Russian NOS. If you want to replace the preamp tubes it's hard to figure out what can be used; this from China-hifi "These 6ж8C、5693、EF6、EBC3、CV592 tubes can replace with 6J8P". They emailed an answer to my question in less than 24hours. Nice people. One thing. The needles on the VU meters don't do anything. This is mostly meaningless, since you can't see them from 6 feet away anyway. The backlights work, which give a nice amber glow. Also according to my understanding of physics, it would be impossible for those meters to waggle without affecting the sound. I'm glad I purchased this app, %100 satisfied. This can't be duplicated in the U.S. without spending at least $1500, especially considering the point to point wiring.

One of the preamp tubes was bad, it was acting like a microphone, euphonic, as they call it. I tried to find a replacement but they are almost impossible to find, so I decided to return the amp. And I am so sad, because it really sounds good (apart from the hum produced by the bad tube or tubes). With the right tubes this could be a very good amp. Sad to see it depart.

Naturally, unboxing the unit is quite the undertaking. I wasn’t prepared for the sheer size and weight, especially when unwrapping it from all its foam, bags, and plastic wrap. It was packaged extremely well and there just is no way the tubes could get damaged with how many layers are protecting them. From the pictures, I didn’t think the A20 would be this big! For some perspective, it's only 4lbs lighter than the A50 and a smidgen smaller, but substantially bigger and heavier than the A10. The volume and input knobs feel more robust and higher quality than the ones from the A10. There are four feet hidden under the unit so it doesn't actually rest on the side gold rails (like I originally thought) giving you 1/4 inch of clearance. Unboxing the tubes will always be my favorite part. The KT88s are beautiful. The rectifier is also significantly bigger than the one from the A10. All the tubes are easy to install and sit snug in their sockets. The KT88s go in like butter, a far cry from my recent experience with the 300b tubes on the A50 that wobbled every which way and didn’t stay secure. Options for the rectifier and preamp tubes are almost non-existent. I messaged the seller about other compatible preamp and rectifier tubes and they responded “We do not recommend customers to replace different tubes, because this can cause irreversible damage to the machine. 6SJ7 could replace 6J8P-J.” Guess I’ll have to put all the money into the KT88s. Although, I am a bit nervous I can't find any backups for the 5Z3PA-T rectifier. I’m using it with the RP600M and just like with the A10, I’m floored by the improvement tubes make with the Klipsch. I tried every excuse in the book to return the RP600M for something “better” but I can’t bring myself to do it off of what I’m hearing. The A10 really needed the Gold Lion KT77 to awaken the potential and sound, but I’m already getting that off the stock tubes with the A20. Even more so, I’m getting even more dynamics and punch. It’s really quite a match made in heaven for the RP600M. I’ve been fully converted to the mindset that Klipsch sings with tubes. Naturally with its size and tubes used, this unit does run hotter and emits more heat than the A10. I have a glass shelf about 6 inches above the unit and it gets much warmer than it did with the A10 in the same location. That being said, this is a bonus for my colder room. That leads us to my 2 nit-picks about this unit. First are the VU meters. I love how they look and I definitely would take them over not having them, but you have to know what to expect. Like others have mentioned, they will not budge if listening to music at a lower or even moderate volume. Even turning up to my preferred listening level, they still move very little. You’d really have to blast it to get them to dance and at that point, could you even see them from your listening position? Also, my right meter was slightly crooked and the left had some of the font cut off (see picture). Also the "ETE" in "METER" is not illuminated at all which makes it look like the needle is mounted in that location as its a perfect dark circle. Not a huge deal. I just like the fact that they glow and look cool. I wouldn’t care if they were even functional. And second, the noise floor on this amp is very audible, whereas I never heard anything with the A10. Since I use the Topping E30 as the preamp, I usually just had my A10 turned all the way up and any volume adjustment would be through the E30. Not so with the A20. Turning all the way up, there is a very obnoxious buzz/hum (still present when I plug the A20 into an external isolation transformer). Luckily this can be significantly reduced by turning it half power and just upping the volume on the E30. Unfortunately, even if you used the A20’s volume adjustment for actual volume and had it much lower on the dial, you’ll still hear a slight hum through the speakers. With the volume knob anywhere from 0 (7 o’clock) to about 60% (1 o’clock) the buzz volume was the same. Past 1 o’clock it starts ramping up substantially so I wouldn’t plan on using these with hard to drive speakers or at very loud volumes. While I’m really enjoying this unit, I can’t recommend it over the A10 for most people. The A10 is $200 cheaper, has a much better selection of tube rolling options (socket adapters that enable the use of 12AX7s are a must!), significantly quieter noise floor, lighter/smaller/runs cooler making it easier to move and place (25lbs vs 40lbs), and personally I liked the appearance more with the 4 pillars in the corners as opposed to the golden rails on the A20. Even so, the stock A20 sounds better to me than the A10 did even with Gold Lion KT77s AND 12AX7s. I even tried the Gold Lion 5AR4 for a complete set (don’t bother, messed with the sound). So if its pure sound quality you are after and nothing else, A20 > A10. But if you are in it for the overall value and practicality, A10 > A20. There's also the debate between EL34 and KT88 but I won't get into that. Lastly a quick note on the A50. I think this was the nicest looking of the 3 units. Love the 4 corner pillars like with the A10, the larger front panel with more spread out VU meters, the preamp tube placement (not obstructing the power tubes, all 5 tubes easily visible) and of course the majestic 300b tubes. Unfortunately, mine started smoking within a minute of power up and my 300bs wouldn’t seat, so I had to return it. Oh well, at least it caused me to purchase the A20! Overall a great unit with fantastic sound! It's a shame this seems to be the forgotten amp between the A10 and A50, as I see those two sell like hotcakes from Amazon, but the A20 hardly goes down in stock. If you are willing to accept some of the compromises listed above then I absolutely would recommend this over the A10. I would also say if you aren’t interested in tube rolling, the A20 is for you. I really didn't like the stock A10 tube setup (namely the Psvane EL34b) and I think everyone should start rolling those ASAP, but this unit already sounds glorious with the stock setup. Either way you decide, I don't think you can go wrong. Good luck and remember to enjoy the music!

The amp is beautiful, well packed, and sounds very nice. Know that there is no headphone output of any sort. These drove a pair of Klipsch KSF 10. 5 (95db) towers pretty well, but even though the amp is solid, there was not a ton of headroom volume wise. I tried another pair (older KEF towers) with a 91db rating and there was no way to get sufficient volume. Know your speaker specs and this amp could be for you.

I wish they would have better quality control with the manufacture of these products ! I quit buying tube amps ten years ago because of the high failure rates. I decided to take a chance again, and once again I got a bad product right out of the box. Lots of noise in one channel, and lightening was arcing inside the rectifier tube ! Of the five Chinese tube amps I have bought in my life, three were failures right out of the box. I am sick and tired of dealing with zero quality control on their part !

I have this amp connected to a pair of Klipsch Chorus II speakers. This is best stereo system I have ever listened to!

Excellent product well built!! Sounds great out of box burning time 100 hours. After that it should sound like I'm in heaven.

Loving the amplifier. Let me tell you my story. I bought a Rotel A-12 amplifier from Best Buy. Within 3 months the Rotel broke. Best Buy would do nothing; and I had to send it off for warranty work. By the way, it has been there for months—about six—and still nothing has been done. The Rotel was connected to Chorus 615 speakers. The sound was not that impressive, but I lived with it. Out of frustration, I went out and bought another amplifier, a tube amplifier—something that I’ve been wanting. The A-20 tube amplifier brought my speakers to life! At 7 1/2 watts, it’s amazing how loud the speakers can get. Now the good/bad news. Before the month was out the first unit started making loud popping noises. I got in touch with the company and they were immediately willing to make an exchange. The new unit has been marvelous. One flaw, the housing does not sit flat on the cabinet. It’s like it has a twist in it. However, I’m willing to live with it since the sound quality is so good. Another challenge is finding YouTubes or other information on tube swapping. I am new to the world of tubes, but I am hooked. Any additional info would be most appreciated.

Original review(3⭐) Replaced the supplied power cord as the hot and neutral were wired reversed, not ideal. Internally the 120v side of the amp is wired correctly, ie hot is switched and neutral remains constant. Worked for about a month, although the power transformer gets up to 62*c during operation and a hot transformer is not a happy transformer, a PC fan now blows on it... it's happier. A month in and the 5z3p rectifier now arcs internally, like a big spark show inside the 5z3p on start up on of the amp, I will attempt to get ahold of the seller to see what we can do... Until then I'm not going to use it until I figure it out; which sucks because this amp sounds pretty good. I will update the review later when I get more info... Edit on September 9/23 (4⭐) (+1⭐) I contacted the seller for a replacement 5z3p and a wiring schematic, they where prompt with their replies. They where more than willing to help me out and shipped a replacement 5z3p which I received a few days ago. (+/- 0⭐)The schematic was emailed to me same day, although it was a diagram for a earlier revision of this amp. BI just traced the circuit and now I have a wiring schematic. (Manufacturer won't release updated schematic to seller) I won't dock stars for this because if you can't accurately trace a circuit/electronics to make a diagram you probably shouldn't be in high voltage equipment like this... ***The voltage/amperage inside this amp is more than enough to electrocute you and have you waking up dead on the floor... if you touch the wrong thing, no pass go, no collect 200$ you just dead*** So clear your browser history before... just in case. (-1⭐)No printed ratings on the transformers or inductors themselves which is kind of annoying as I now have to put these components on a oscilloscope and wave generator to figure these ratings out. The info given in the product description for these components isnt really useful; Listing the physical dimensions of the transfomer/inductor and it's lamination thickness, doesn't tell you much about its electrical properties. Listed voltage/amperage of all the windings would be better or at least the turn ratio of all the windings. (Editing this would net y'all 5⭐) -Would I recommend this amp? Yes for someone with/knows someone with vacuum tube amplifier experience to do the required maintenance and mods or someone that is technically minded and carefully wants to learn about vacuum tube electronics. However I cannot recommend it to someone that just wants a no maintenance amplifier, as this amp needs a little bit of modification to reduce the stress on the 5z3p rectifier. (I still need to test and see if a 5u4g rectifier is a good no mod bandaid for this.) In stock form your going to burn through a 5z3p tube every month or so depending on use. The first filter capacitor installed is a 10uf 450v epcor axial electrolytic; The 5z3p tube spec sheet calls for a first capacitor max of 4uf. The 5z3p doesn't like the sudden rush of power that is required to charge this capacitor during start up, eventually leading to rectifier flash over. You might have more luck with a 5U4G rectifier tube as it calls for a max filter capacitor of 40uf, but doing so may alter the voltage inside the amp, so do so only if you know what your doing.