My previous system was comprised of Harvey Rosenthal modified Mingda 3008A monoblocks driving the top and mids and a Parasound A21 driving the base of my Tekton Double impact speakers. The Preamp was a David Shulte modded Parasound JC2, an outstanding piece before the mod, extraordinary after (Shulte is an absolute magician; the late Harvey Rosenthal knew everything about any tube circuit ever used.). It conveniently has two preamp outputs and both amps have their own gain adjustments, so I was able to balance the system.
The decision to buy the Muzishare R100 (805) version was based on a desire to simplify my life. Having used both, I have a preference for certain aspects of both technologies. As many have said, in general, tube amps are not known for their bass performance. I must say that the Mingda monoblocks provided adequate bass with the Double Impact speakers at 98+Db efficiency, the bi-amping being something of a tweak to get even more bass depth and solidity. I listen (mostly) to classical music, and am sensitive to sound stage presentation and tonality.
Out of the box, the Muzishare sounded different, surprisingly different. According to the vendor, the amp does not sound "acceptable" until about 30 hours of use, then improves quite a bit by 100 hours, and achieves near peak performance at 300 hours. At first, after a short listen to it as an integrated amp, I naturally assumed that driving it with the Parasound preamp would produce the best results, so that is how I listened for quite a while. Nevertheless, my friend Sandy of sandy@levyphoto.com, an expert in things tubes, and I both thought it sounded "very good" almost right out of the box, with the stock tubes.
The vendor suggested listening to the amp for a year with the stock tubes, but I have no such patience. Some folks like vinyl playback equipment because of all the tweaking they can do to maximize performance. I believe the same thing to be true with vacuum tube amp owners. If you don’t believe me, check out the prices of some NOS tube types on eBay.
Although I could here describe my experience with each tube change, I’ll get to the (current) bottom line. There is an old saying among tube folks that they would prefer a modest amp with great tubes over a great amp with modest tubes.
One has not scratched the surface of the R100’s performance with the stock tubes. While I have rolled tubes in many different amps and preamps during my 45-year audio life, I have never heard a unit that is so revealing of tube changes.
One of the biggest surprises came with the change to the rectifier tube. I went online looking for recommendations for the "best" 5U4s. I looked at rectifier cross-reference/substitution tables. During this process I discovered in my tube box a rectifier made by Mullard with the Haltron label, that is on eBay for ~$300. I could not resist briefly installing it to see what the fuss was about. The fuss is fully justified. But given its value, I quickly removed it from the amp and stuck it back into inventory.
I found that I also had a bunch of NOS tubes with Westinghouse brand labels of the same rectifier type. I stuck one in and listened to it for a while. Then, after about a week or so, the tube just failed. Hey, it happens with tubes. It has always happened, albeit not as frequently as some folks believe. So now I am listening with another of those tubes and so far, so good.
I read that an earlier version of the 6SN7 is really good, but requires an adapter for the anode cap. I will try those, too. Somewhen down the road, I will replace the 300B tubes. The prices of those are really ridiculous, so it will have to wait.
So far, with upgraded tubes, the R100 has been transformed. The iron and the internal components must be pretty good. The tranny windings for 2021, I read, use OCC copper along with the Japanese-made cores.
Regarding the bass performance....
I still have the Parasound A21, just in case, but with the tube rolling I have done, just in the preamp stages and rectifier of the amp, the bass has become excellent. On orchestral music, rolling kettle drums and bass instruments sound like they should. I played the Mercury reissue, of the1812 overture remastered by Wilma Cozart-Fine, the one with real cannons and carillon. It is amazing. Nothing is lost. The cannon shots sound real, better than they did with my old setup. The dynamics and tonality of the carillon must be heard to be believed. (That 1812 Overture disk is now on my list of demo disks).
Organ music, and the low frequencies on The Gladiator, also are all there.
My suspicion has always been that tube amps can produce bass just fine, depending on the speakers with which they are used. I the "good old days" when all they had were, by today’s standards, relatively low power tube amps, all they used was high-efficiency speakers. There was no bass shortage. And I don’t have a shortage with my setup. Of course, YMMV.
As bass drivers got smaller in order to fit in the box sizes for the home, by necessity the throw of the bass drivers got longer, requiring a higher damping factor from amps. Also, lower speaker efficiencies required more amp power. So beware of generalizations about tube amp bass.
In any case, after some more time passes and I can attest to its reliability, I am like to highly recommend the Muzishare R100 (805, 50 wpc) version (I haven’t heard the 211 or 845 versions). Candidly, I bought the 805 version for two reasons. The first was that I was familiar with the sound of the 805s from the MingDa amp, and second, should I need more power with a future speaker change, I may not need to switch amps.
One tip: I have put some small quiet fans on top of the trannies to blow some air across the tubes. I am told that may help them live a longer life. At low speed, the fans are inaudible from the seating position. IDK, but it couldn’t hurt. I have found that tube dampers, properly used also make a nice difference by reducing vibrations and microphonics. Remember tubes stick out of the amp and are exposed to the vibrations of the music. Also, even the best transformers also produce vibrations. Try dampers. They are an inexpensive effective tweak. I won’t tell you that I get mine from sandy@levyphoto.com lest you think I am schilling for him.
Over the years I’ve had planar speakers, both electrostatic and planar magnetic, and several different "standard" speakers. For a while, I was even a part-owner in a speaker company. IMO, the Tekton speakers may be the best value in audio. The Muzishare, although not cheap, also appears to be of tremendous value. Even the highly toted Line Magnetic amps don’t use a rectifier tube except in their much more expensive "Pro" line. The inclusion of a phono section for MM is also a nice addition, although I have no idea how good or useful it is. Nevertheless, for someone who just wants to move back to vinyl, it could be a nice starter phono section.
P.S. I have no ownership or distribution rights or any interest in any product or service provider mentioned above.
