Remove 15k, or use 10k trimpot instead 5k6 to set bias. Heatsink temperature must be 60deg maximum.
Last edited:
ok it`s olafk time to post the blak&white home etching friedly pcb.
Last edited:
There is plenty of space on Olaf's FA9 pcb to add bypass caps from the rail lines to ground close to output transistors. It will improve stability. At least 220nF very close to output transistor, and, if possible, another 100uF. If necessary use jumpers.
Hi, what can I say? I listened 10 minutes to the music, then it was too hot. The heat sink was too small (0.9 K / W), or I should have set a lower current.
Anyway. A new set of fets and everything goes again 🙂
Thanks to Mile for a nice amplifier!
regards Olaf
Anyway. A new set of fets and everything goes again 🙂
Thanks to Mile for a nice amplifier!
regards Olaf
Heat sink is too small... use some fan if you want to do more tests. Heat sink must be minimum 3x larger than your.
There is no need to use small IRF540/9540 when 240/9240 are cheap. TO220 metal tab is small and you have a lot of heat concentrated on it. Bigger tab will conduct heat better to the heatsink.
Yes everything correct. But I like the little IRF's. They have a very nice sound. And so what! It was clear that the heat sink was too small, but I'd like to build a Class-A amplifier at first time. I will get bigger heat sinks and build a nice housing.
Main feature, the circuit works!
regards Olaf
Main feature, the circuit works!
regards Olaf
IRF540 is little TO220 but 100V 28A 150W, compare to IRFP240 in TO247 with 200V 20A 150W.
AA9 and FA9 is new reference in diy class A amplifiers.
Regards
Hi, I want to build a 5.1 channel amplifier kit using this amplifier design. Six amplifiers will work together to feed my speakers mainly with 4 to 6 Ohm resistance. I decided to separate the PSU from the box which these amplifiers will fit in and make another isolated box for PSU. I have searched for best well-priced transformers and found Vigortronix-146-1000-250(1000VA-2x50V) is suitable for me. This transformer and rectifier unit including all capacitors, diodes,... will take place in their specified PSU box and the outputs for each channel will be connected through shielded cables to amplifiers PCB containing box. I do not have enough information to design my own switching kit and my question is about how can I feed six of these amplifiers with separated output/input for each of them? Should I use 6 different PCBs or can anyone help me build a single rail output? And my other request is:"Does anyone have Gerber file for this amplifier design?" I want to order manufactured PCB instead of making them by myself. Excuse me for writing and asking too much. Regards.
Unfortunately, specs quoted are of little relevance when these transistors are used in audio circuits. In fact, IRF540 fails frequently even in low power AB class circuits if Vbe multiplier is not implemented. Big heatsink is necessary!