Iz top quality, so you not worry!
Ah, the wonders of China. Cheap, high quality mass-produced goods. 
This here amplifier claims "100W+100W". Over an unspecified load impedance, for an unspecified length of time and with an unspecified amount of distortion. It has been quoted to me as 40wpc real power. Most i could get out of it on a 4.3 ohm dummy load was 60W, one channel driven. So the 40wpc claim seems to be true - from here to "100W+100W" there's a long way.
Just look at this thing. Tiny transformer, tiny heatsink, and a tiny fan (60mm) making not so tiny noise. Actually, the fan noise is pretty much on par with the volume of the music coming out of the amp... and the fan runs maxed all the time. That is, unless the amp is turned up loud, when the fan will slow down because the transformer voltage drops significantly. So, we have a fan that runs fast when you don't need it. Brilliant!
Main filter caps are one taller than the other. On both of them it says 4700u 35v though. Which btw is not only too little capacitance, but also with the crap regulation of this transformer they will blow on high line if the amp is left idle.
Output transistors are 2SD1047. Which would be enough for the job, but that heatsink is really flimsy. If the fan seizes they will most definitely go boom as there is no thermal protection. The drivers are 2SD667/2SB647, and the small signal transistors are 2N5401/2N5551. When delivering 60W on one channel the rails sag from +/-30v to +/-26v which is pretty poor performance.
So how does it sound? Well... cheap. The input sensitivity is too high, leading to a healthy amount of background hiss and hum. It goes into clipping at less than 1/3 volume, with a consumer audio source (laptop). And they call this "professional"? The volume pot turns too easily. The mike input adds even more hum when engaged. Lovely.
This kind of thing retails here for $70. You'd be much better off getting a vintage amp for that price. You may need to swap out some caps in a vintage amp, but on this pile of trash you'd have to rebuild the whole thing to get something useful out of it. I don't really care about its current guts tho - the plan is to throw a couple Class D modules and a SMPS in there.
This here amplifier claims "100W+100W". Over an unspecified load impedance, for an unspecified length of time and with an unspecified amount of distortion.
It has been quoted to me as 40wpc real power. Most i could get out of it on a 4.3 ohm dummy load was 60W, one channel driven. So the 40wpc claim seems to be true - from here to "100W+100W" there's a long way.Just look at this thing. Tiny transformer, tiny heatsink, and a tiny fan (60mm) making not so tiny noise. Actually, the fan noise is pretty much on par with the volume of the music coming out of the amp... and the fan runs maxed all the time. That is, unless the amp is turned up loud, when the fan will slow down because the transformer voltage drops significantly. So, we have a fan that runs fast when you don't need it. Brilliant!
Main filter caps are one taller than the other. On both of them it says 4700u 35v though. Which btw is not only too little capacitance, but also with the crap regulation of this transformer they will blow on high line if the amp is left idle.Output transistors are 2SD1047. Which would be enough for the job, but that heatsink is really flimsy. If the fan seizes they will most definitely go boom as there is no thermal protection. The drivers are 2SD667/2SB647, and the small signal transistors are 2N5401/2N5551. When delivering 60W on one channel the rails sag from +/-30v to +/-26v which is pretty poor performance.
So how does it sound? Well... cheap. The input sensitivity is too high, leading to a healthy amount of background hiss and hum. It goes into clipping at less than 1/3 volume, with a consumer audio source (laptop). And they call this "professional"?
The volume pot turns too easily. The mike input adds even more hum when engaged. Lovely.This kind of thing retails here for $70. You'd be much better off getting a vintage amp for that price. You may need to swap out some caps in a vintage amp, but on this pile of trash you'd have to rebuild the whole thing to get something useful out of it. I don't really care about its current guts tho - the plan is to throw a couple Class D modules and a SMPS in there.
Attached Files
The fan is made by Adda btw. I forgot to take pics - will do when i feel like taking it apart again. Gotta love the notice on the back - there's some more but the first one is killer: "This fan is for ventilation use." Duh! 
Now at least i have a semi-usable volume control. I was in for another surprise tho - the LED meter isn't wired at the output of the amp but at the output of the preamp/EQ... after the first 1k resistor you see in the schematic. So now the blinkenlights no longer reflect what's going on with the sound - they max out long before the amp distorts. Ah well... i'll fix them some other time.
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