Did anyone check out the recent article in Elektor Electronics? There's a class A/B amp, very low noise, discrete and through hole design.
https://www.elektormagazine.com/labs/fortissimo-100
To my eyes it looks kind of interesting. Symmetrical and pleasing to the eye. I can't judge the design, though, but interested if someone has any opinions about it.
The ThermalTrak transistors from On Semiconductor makes it a bit expensive to build and they seem hard to get right now, probably due to usual component shortages.
https://www.elektormagazine.com/labs/fortissimo-100
To my eyes it looks kind of interesting. Symmetrical and pleasing to the eye. I can't judge the design, though, but interested if someone has any opinions about it.
The ThermalTrak transistors from On Semiconductor makes it a bit expensive to build and they seem hard to get right now, probably due to usual component shortages.
I began building this in the summer. I would recommend the kit, because sourcing the parts was a hassle and became very expensive. I had to get them from many different locations. The transistors (at the time) were not available at my regular suppliers.
For transistor biasing, they used LEDs with rather low forward voltage, because when I used some random LEDs, the current in the interstages became too high. You could lower the current in the CCS, but the LEDs already operate near their lower end and could easily begin to differ in forward voltage (non-linear range). So I ordered the same LEDs they used and the forward voltage dropped a bit. It was still causing too high current (in my opinion), so I lowered the current in the constant current source a bit.
The transistor matching is a hassle. I created a PCB to make the transistor matching easier, but I don't know if I had the patience to really wait for temperatures to stabilize to find the right pair of transistors. If I would do it again, I would really reserve the time this needs. There is some drifting up and down in the circuit because of this, I think.
It's not ready yet, so I don't have any real conclusions. Only tested with a dummy load, so far.
In the picture, the power supply is a cheaper chinese LLC SMPS. Seems to work...
For transistor biasing, they used LEDs with rather low forward voltage, because when I used some random LEDs, the current in the interstages became too high. You could lower the current in the CCS, but the LEDs already operate near their lower end and could easily begin to differ in forward voltage (non-linear range). So I ordered the same LEDs they used and the forward voltage dropped a bit. It was still causing too high current (in my opinion), so I lowered the current in the constant current source a bit.
The transistor matching is a hassle. I created a PCB to make the transistor matching easier, but I don't know if I had the patience to really wait for temperatures to stabilize to find the right pair of transistors. If I would do it again, I would really reserve the time this needs. There is some drifting up and down in the circuit because of this, I think.
It's not ready yet, so I don't have any real conclusions. Only tested with a dummy load, so far.
In the picture, the power supply is a cheaper chinese LLC SMPS. Seems to work...
I too have an Elektor Q-Watt amplifier experience. Built and running daily since built.
https://www.elektormagazine.com/magazine/elektor-201309/23330
The output IC1 = LME49811TB and T4 = MG6330-R; T5 = MG9410-R were almost obsolete when this article came out in 2013.
There were numerous hic-ups.
https://www.elektormagazine.com/magazine/elektor-201309/23330
The output IC1 = LME49811TB and T4 = MG6330-R; T5 = MG9410-R were almost obsolete when this article came out in 2013.
There were numerous hic-ups.
Way back in the 90's, I built an active subwoofer from an Elektor article (https://www.elektormagazine.com/magazine/elektor-199604/33554). I never got the amplifier working, I didn't have the skill/resources at the time (home built PCBs, burned output transistors). The amplifier was interesting/different though, it used Toshiba IGBT audio output transistors. I ended up keeping the active filter and used a Hypex 400W power amplifier module instead.
Last year I rebuilt the amplifier chassis, because of poor build quality (old home built chassis). This time a better aluminium box, rebuilt active filter PCB and added Mooly's speaker delay.
Last year I rebuilt the amplifier chassis, because of poor build quality (old home built chassis). This time a better aluminium box, rebuilt active filter PCB and added Mooly's speaker delay.