I got some experience with Music Angel, but with the 845 amp.
Now you are correct, they are really really cheap.
The one you got there is REALLY cheap..
Bought my amp the 845 ONLY for rebuilding it completely, and did so.
Wanted to get some more experience in Tube amps, didn't have any clue at all.
Oh that is not all true, bought a kit something K-502 11BM8 something push and pull amp, but it was so extremely simple and easy to make there where no learning in the process.
The sound also was much related to the size of the transformers and price..
Anyway back to the MA 845.
Out of the box it sounds terrible, or it sounds better than regular commercially available A/B amps, in most cases, but still horrible..
Actually I didn't even listen to mine before starting to tweak and rebuild it.
I just tested that there was sound first on left channel, and then in right channel. It was OK.
After rebuilding it quite a lot, following some others drawings and idea's, it sounded still bad, cause the Chinese tubes in preamp and driver stage was completely HORRIBLE.
I changed these, and it sounded fantastically good, but didn't have any power before distortion...
After a lot of investigation I found this amps power supply was completely different than the one they made just weeks earlier.
There even where missing some of the chokes pictured at eBay.. ERR:.
So the power supply had to be rebuilt too...
Now it got better, but the power transformers got so hot I could barely touch them..
So i got me a variable Isolation transformer and adjusted it to 220v exactly. Still just as hot..
Just left it like that, and used it for quite some time, rebuilt all the circuitry inside a couple a times more...
Finally it got very nice, and this still with the originally supplied 845tubes, or not them, but some of the same type I ordered, since the ones with the amp was completely messed up.
AND it was not during transport, it was either done at the factory, or it was done when they carelessly tested the amp... Anyway, I denied taking these damages at the transporter insurance, since it WAS NOT A TRANSPORT DAMAGE...
Well so then they denied paying anything, and I bought my own tubes.. Just as well, I AM not a LIAR and a thief, so it was just fine.
The sound from this amp is nothing short of fantastic, after all tweaks and fixes, especially if compared to the price.
BTW, I used only 6H8C tubes both in pre and driver stage, these had plenty of gain.
OF course changed resistors and power supply changes to make these fit to different current drawn.
After a lot of adjustments and finalizing the output noise was lower than 1mv at 8ohm output terminals.
4ohm tapping was useless, even on 4ohm speakers and had NO power AT ALL. 8ohm output was doing fine from 6-8ohm speakers.
Later it cough fire, and I'm glad the building it was in didn't burn to the ground... Or got badly messed up.
IT smelled in there for weeks, if not months.
HAD to repaint the walls to get rid of the smell..
Now in the later day's I think the cause for the total meltdown has been found.
Since they had rebuilt the amp, since the tweak drawings I had was made...
The filaments where somehow differently connected, so they had another voltage level to ground.
This most likely caused it to fail.
I'll check this further, as a friend of mine has one like it. And of course this one also tries to melt down from time to time... For now his PCB-traces has just been blown away instead.
There are of course NO FUSES anywhere inside the amp. So complete meltdown is the fuse.
Like you say, it is really cheap, cheaper than to buy all the parts and build it.
When it comes to my amp, well... I could have gotten a pretty good set of Lundahl transformers for the price I paid including shipping. Now this is the only things usable on this MA amp, the output trans..
Wisdom, yes lots of lessons learned, and got much more experience with tube amps and datasheets for such things.
It was worth it, absolutely worth it. For a beginner that want's to learn it's perfect.
IF YOU ARE AWARE OF THE HIGH VOLTAGES INSIDE, AND TAKE PRECAUTIONS THEREAFTER.
BTW, the schematic for my amp didn't match real life at all.
Maybe they have improved, after they have absolutely didn't.. or they ran out of parts, and just redesigned it to fit the available part list?? It's hard to say.
For some business is business, and they're only concerned for the income that particular day
What was it that caused the world financial crisis again..
Oh yes, no plans for the next day, so they're not alone.