First Watt my way.
Actually puts out 2 Watt with acceptable distortion.
But not much more. Depends on the supply voltage which is 20 Volt single end.
Actually puts out 2 Watt with acceptable distortion.
But not much more. Depends on the supply voltage which is 20 Volt single end.
The way to improve that scheme is to increase drive to the output transistors. Make the bootstrap a pair of 82 ohm resistors and U2 one of those old D40K type darlingtons.
EF2 has a larger crossover region, period. Unless first stage of it stays in class A. Also robs 2 Vbe. When those two vbe are a significant fraction of the supply voltage, you may not want to part with them. Running off 6-12 volts, EF1 is the way to go unless you are trying to drive 2 ohms or something. Unless you can find a nice pair of Ge’s and can make or find a totem pole driver transformer. I had a number of old car radios that did that - and they played cleaner than any modern (non-high-power) ones using those stupid chiplifiers. I mentioned I found a way to make those sound good, but damn it generates heat.
This true, but don't exaggerate it.
The it is not a problem to keep the first stage of EF2 in class A. With a proper VBE multiplier, the output impedance of the first stage could be way lower than the input impedance of the output stage. Crossover region won't be affected that much.
PP EL84 triode running class A driven by an ECC81 LTP. All poly caps including the PS. Based/inspired by Eli’s El Cheapo
Based on chassis and iron from a Scott LK48/222. Once stripped the holes are left.
dave
My 2-cents in Tube Flea Watts:
No input/driver tube, no phase splitter, still push-pull 🙂
EL84 Ultralinear, it doesn't even make it to the first watt without a potent pre-amp.
No input/driver tube, no phase splitter, still push-pull 🙂
EL84 Ultralinear, it doesn't even make it to the first watt without a potent pre-amp.
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Oh It look almost same my amp.
first I build up JLH amp . after 02 days have reason amp so hot & it using alot of power waste . I modify it as same this circuits then i can adj bias to get litter bit class A then feel it better than original JLH amp.
@dungdochi1978
Nice 🙂
With only one opamp and two transistors it is possible to design a low power amplifier.
This little amp has low distortion, while it can put out no less than 5 Watt.
All components are through holes.
Supply is regulated +/-12V
Nice 🙂
With only one opamp and two transistors it is possible to design a low power amplifier.
This little amp has low distortion, while it can put out no less than 5 Watt.
All components are through holes.
Supply is regulated +/-12V
Say we have speaker pair with sensitivity SPL of 90dB per Watt.
Then 1 Watt will give soundpressure 90dB at 1 meter.
As there are 2 speakers the SPL will be 93dB at 1 meter.
But you listen at a distance of 3-5 meter, so the SPL at listening position will be less.
Anyway, you come a long way with only First 1 Watt.
Then 1 Watt will give soundpressure 90dB at 1 meter.
As there are 2 speakers the SPL will be 93dB at 1 meter.
But you listen at a distance of 3-5 meter, so the SPL at listening position will be less.
Anyway, you come a long way with only First 1 Watt.
How low can one go?
Here is a 3 Watt amplifier based on LM1875.
LM1875 can have +/-8 Volt as the lowest supply.
But don't fool yourself - it is real Hifi = very low distortion.
Here is a 3 Watt amplifier based on LM1875.
LM1875 can have +/-8 Volt as the lowest supply.
But don't fool yourself - it is real Hifi = very low distortion.
@ Fleapower < 1 watts, 0,05% distortion, not bad i.m.o. I have 16 pieces of genuine LM3875 lying around, maybe I should try a battery 12v powered amp.
