OCL Amplifier Board Kit Dual 100W High Power Two-Channel Pure Final Stage DIY Audio Stereo Amplifier Module Parts

I've followed recommendations by other reviewers and replaced C3/C6 with 101 (100pF) and R23 with 20K - other than that - it worked just fine OOB. Sound quality and volume are very good. Assembly is easy and can be done without manual that is in Chinese (you can use google lens to translate). All in all - great kit!

Purchased one and returned it. Purchased a second one and it did not work either. Reading the reviews I found a review that stated it would not work as the kit was supplied. The review offered modifications to make this kit work. I tried his recommended modifications and yes it did in fact make the amplifier work. So no dice for me people.... I bought two and neither of them worked, until I modified the second one. (And by the way yes I know how to solder that wasn't the issue.... I've been in electronic repair ever since I've become an adult many years ago LOL

Based upon other reviews, I tested all components prior to building. All were delivered and tested out ok but glad I did anyway. Based upon other reviews, I looked for errors in the schematic/documentation and only found one schematic error. R11/R22 is marked as 240 ohm in schematic, but is marked as 220 ohm on the PCB. I installed the (delivered) 240 ohm resistors. The amp "worked" after assembly, but poorly. I changed R6/R17 to 22k and R5/R16 to 1K. This sets the amp feedback for a more "typical" gain of 23. I also reduced C3/C6 to 100pf which increased the slew rate/frequency response. With these changes, the amp has good frequency response and seems reliable for 10W RMS per channel into 16 ohms. Not sure I would push it much past that. I did not trust or use the english translation of the documentation. I bought this to play around with class AB amps, and for that purpose it was a bargain. YMMV.

Can be used as car stereo amplifer

This kit came well packaged and the board, as stated in previous reviews is clearly marked, albeit with a few errors on the silkscreening regarding resistor values. Follow the schematic, along with the silkscreening on the PCB and it practically assembles itself. I certainly had $15 worth of fun assembling this kit. Now on to the nitty gritty. DO NOT EXPECT THIS KIT TO WORK OUT OF THE BOX! Nearly half of all of the small signal transistors were DOA with an HFE of 0 and two of the output transitors are weak, with an HFE of 20 or less. Having considered the price of the kit, I pretty much expected this, along with suspect quality capacitors. The heatsinks are laughable at best, and will need to be immediatly replaced with something capable of dealing with the output transistors thermal waste. It is recommended that a dc protection circuit be added to the output in order to save your speakers in the event of component failure. Overall a great little kit. Cost to complete : Kit - $13.99 Replacement components - $30-40 Power xformer - $40 Softstart /Speaker Protect $50 Enclosure - $28.95-$Unlimited For about $200-$700 you'll have a decent little home built amplifier

I have built many powet amplifiers and this one inspires me. Recommended.

I am accustomed to working on many types of electronics and understand schematics and polarity for all components listed, soldered all correct parts as pc board had printed, had to buy external ac transformer with center tap so 18 volts on each end and when powering up, just get a hum. Nothing works. Wouldn’t recommend.

Great item