nippontiger  

I found an amplifier kit from Hifidiy.net - a Chinese company supplying DIY audio kits.
HIFIDIY mini-A power amplifier A20 Assembly Instructions
Basically, its a 20W class A amplifier. The kit comes complete with PCBs, components, what looks to be a 200 VA toroidal transformer, 40,000uF in the PSU, heatsinks and a nice, shiny case.
Im living in Japan at the minute and because of the strong yen, this kit would cost very little. (less than 200 pounds in real terms)
I was wondering a few things:
Has anybody built this kit?
Has anybody any experience with hifidiy.net kits in general?
Unfortunately, I cant find a circuit schematic, but does this look like a decent amp for a beginner to build?
Also, Im a bit worried about the lack of proper English instructions - I dont think I'd have to much trouble populating the PCBs and wiring it up, but in the assembly instructions (looks like they used google translator!) theres a section describing what looks like amplifier set up - perhaps setting the bias? The English translation doesnt make any sense! There seems to be more pictures on the Chinese assembly instructions.
HIFIDIYСÐͼ×ÀàA20¹¦·Å×°»ú˵Ã÷(ÕýÔÚ¸üÐÂ, ÓÐÎÊÌâÇë¸úÌù,ÎÒÃÇ»á»ã×Ü) - HIFIDIY ²úÆ·×ÊÁÏרÇø - HIFIDIYÂÛ̳ - Powered by Discuz!
I have some Chinese friends who could, perhaps, help me with the Chinese, although they know nothing about electronics.
The other thing I was wondering, I believe the trans is set for either 115 or 230 V operation - this would suit me as Id need it in 115 V for Japan and 230 for when I move back to UK - would it be just a case of rewiring a couple of leads on the transformer to make the change?
Thanks.

unclejed613  

at 20W, there's no such thing as mini in class A, as you need a very large heat sink....

unclejed613  

at 20W, there's no such thing as mini in class A, as you need a very large heat sink.... note to self, avoid the use of the BACK button

Telstar  

The heatsinks on the pictures dont seem to small

__________________
"The total harmonic distortion is not a measure of the degree of distastefulness to the listener and it is recommended that its use should be discontinued." D. Masa, 1938

nippontiger  

yeah, not sure why they call it "mini" - thing weighs in around 13kg, those heatsinks are about 30x13x5 cms each!

jacco vermeulen  

It's a downsized Krell KSA50.
MJL3102/3281 outputs, MJE15030/31 drivers, 2SD669 Vbe device, MPSA+MJE Vas devices, A970/C2240 input transistors (some even use MPSA42/92)

__________________
Not so much,.......if it says "ZM" in the corner.

vinyl dragon  

For £200 it looks like a bargain and given the difficulty in translation etc will also provide a lot of entertainment.
Don't really see that you can go wrong.

nippontiger  

I might give it a go! Seems like the most difficult part might be working out how to pay using Yen - Japanese banks are absolutely awful and its difficult to get a credit card here as a foreigner!
If I manage to get the kit, I will post my experiences.

HIFIDIY  

Yes, it is a chass A amplifier, the specification is like this :
Frequency response(HZ) ：5-100K
Output power (watts) : 25(Class A)/100 (Class AB)
Total harmonic distortion: 0.01%
Size( W*H*D) (CM): 25*13*32
The Net weight (Kg) : 13kg
more information can check on http://mall.hifidiy.net

GTHICM  

For what it is worth, I have built several of their kits, including a cd transport and TDA1541A dac. The boards and parts are all of top quality and the caswork is very nice as well. A little time is necessary to figure out the instructions, but this has become much easier than several years ago when I built the cd transport kit, which was fun to build and works very well to this day. There is a lot of value for money here so you need not hesitate on account of any concerns like that. I trust that you would not be disappointed if you decide to pull the trigger.