You may choose the varistor type and clamp voltage to feel safe, like 30V. This excludes the resistive current which is frequency independent. I use varistor for the reason it has very high resistance until the clamp voltage is reached. The method with a resistor, R//C, is almost equivalent. dual-mono with 2 toroidal PSU transformers 300VA each It only tells that pure resistive loads are inadequate for both simulation and testing and do not reflect real-world speaker load.Īnother interesting points of the schematics are the Q16 emitter follower (beta enhancer) that greatly reduces VAS distortion and increases open loop gain and all the current sources that improve PSR (ripple rejection). Interestingly enough the amp may drive purely resistive load of 2 ohm up to full output swing and still stay inside allowed SOA boundaries. This is the complete schematics of the amplifier that I built I was thinking about my favorite and robust MJL21194/93 first but then decided to go for MJ元281/1302 pairs, which have even better linearity at high currents and are faster, though only very slightly weaker in SOA. The main change I made was to use 2 pairs of the output devices, to get more output current and power and less dependence on load impedance. The original Luxman PB-1037 main amplifier circuit is more different with 2 differential stages instead of one, no use of EF VAS buffer has made very good job in implementing improvements by Douglas Self (EF buffer before VAS etc.) and his circuit posted was a temptation to me to get even more power and less distortion from that circuit. The circuit posted in the link above is called “Luxman L-85” but in fact the topology is rather the Douglas Self's “Blameless Amplifier” discussed in his book Audio Power Amplifier Design Handbook on also on his website

Hello all, the thread posted here by me to build a new DIY amplifier functional sample.

DIY 250W/4ohm power amplifier based on “blameless” topology

Power amplifier diy