I can believe that on music but when you test with a continuous sine it is far more demanding. One great option if you want to test is to use a tone burst of say 10 cycles at 1Khz .
It looked very similar to the Hitachi design to me. But has added diodes & zeners that probably are to limit the voltage drive to the Fets which increases their survivability into a short circuit. If its not getting warm it could be usefully biased to sink some more current - easily measured across one of the fuse holders .
It does not have even the most basic improvements to the design such as a CCS for the input pair - But no worries some people prefer the simplicity of a resistor and it helps to avoid a transient when switching the amp on.
I would definitely re-cap the board & dual dies mosfets would allow more current into a difficult load which could suit the ATC SCM40 speakers.
My Hi-Fi system uses 4 Lateral fets per channel & is good for 250W into 4 ohm loads.
It does not have even the most basic improvements to the design such as a CCS for the input pair - But no worries some people prefer the simplicity of a resistor and it helps to avoid a transient when switching the amp on.
I would definitely re-cap the board & dual dies mosfets would allow more current into a difficult load which could suit the ATC SCM40 speakers.
My Hi-Fi system uses 4 Lateral fets per channel & is good for 250W into 4 ohm loads.
Thanks for your input, I did recap the board a few months ago. Your suggestion of the dual dies mosfets sounds intriguing 🤔
Cheers
Cheers
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Be careful not to confuse the author of this thread, here you are talking about the Maplin, not the amp which is the subject of the initial request
As I don’t have the knowledge of you guys I will be leaving the amps well alone.
;-)
To achieve an audible doubling of volume, a tenfold increase in power would needed.
Doubling the power yielded 3 dB, on paper. 3 dB is audible, but not much.
To achieve an audible doubling of volume, a tenfold increase in power would needed.
Doubling the power yielded 3 dB, on paper. 3 dB is audible, but not much.
I did this once, upping the power of a good solid state power amp removed from a name brand receiver. It was rated in the old good ways: 60 watts RMS 20-20K, 0.1% distortion, etc etc. What I did was replace most of the transistors with higher voltage/curreht ones, larger zener diodes to account for a 120V power supply up from about 70V, larger emitter resisor wattage, etc etc.. In the end I got a ton more power, about 200W into 8 ohms. The only drawback was that the heatsink was suddenly much too small, requiring an annoying noisy fan.
But was it worth it? probably not, because if I were not so frugal I could have simply bought a bigger amplifier.
On the upside, this all went into a nice polished aluminum rackmount chassis with two 3" power output meters and an added 2-inch X-Y oscilloscope which was good for seeing when clipping on peaks.
But was it worth it? probably not, because if I were not so frugal I could have simply bought a bigger amplifier.
On the upside, this all went into a nice polished aluminum rackmount chassis with two 3" power output meters and an added 2-inch X-Y oscilloscope which was good for seeing when clipping on peaks.
You can throw enough money into anything and achieve some limited results. The question in my mind is it worth the cost for a very very small increase in power and I would have to say no its not. Double the power and you will get a 3db difference in level. What you have seems to work and while it isn't the greatest it is capable of providing an amount of enjoyment. If you jack around with it the chances of it staying stable will decrease and so will its willingness to stay together without emitting some magic smoke.
YES it is possible! invert 1 channel. Hook a subwoofer across both speaker outputs. Now you have a bridged output. This will give you more power. BUT hook up the midrange and tweeters as normal for 1 channel and backwards for the other channel. They will not be bridged. thus only the woofer is bridged and the rest is normal. There you have it.