About me : I live on Majorca-Island and I am building amplifiers and active speakers for a number of friends and clients although I am retired.
When building the above there is the question of what power-supply to use for the gear I am building.
Since the speakers generally are stationary and 3-way units with 12“ bass drivers they already weigh from about 30 Kgs and upwards. The amps weigh less but are stationary as well . So , in both cases , the absolute weight is secondary .
Concerning the amplifiers those can all be executed as BTL which allows for surprising output with one only rail without large output capacitors . Depending on the rail voltage one can reach 100 w with 8 ohm speakers and 200 if 4 ohms are used , with no problems at all .
Any amplifier needs a strong and clean power-supply to be able to output a good bass which implies a relatively high cost for rails between 24 and 50 volts and currents up to between 10 and 20 amps even if it´s only for impulses
Due to all of the above I have successfully built several units with a different concept for the power-supply :
I have used 2 , 3 , and 4 12volt 7Ah AGM-batteries in series ( weight is aprox. 2 kg per battery ) with two parallel capacitors , one of 4700 uF and one 4,7 uF . The internal resistance of one battery is only about 23 mOhms so less than 0.1 ohm for 4 of them and the whole buffered with the two parallel capacitors.
The charging power-supply can be any switched power-supply with an output of 50 watts or more followed by a buck or boost module adjusted to 13.8 volts per battery so 27,6 for two , 41,1 for three.
Disadvange is the weight , advantages are that it is practically noise-free , and extremely high current capacity , cost of about 60 bucks for the whole thing . I obtain the current capacity of a very large transformer-based power-supply ( Which is not a light weight either ) and the stability of an SMPS , and even considerable immunity from power failures .
I love to do unconventional things and I would love a discussion on the subject.
When building the above there is the question of what power-supply to use for the gear I am building.
Since the speakers generally are stationary and 3-way units with 12“ bass drivers they already weigh from about 30 Kgs and upwards. The amps weigh less but are stationary as well . So , in both cases , the absolute weight is secondary .
Concerning the amplifiers those can all be executed as BTL which allows for surprising output with one only rail without large output capacitors . Depending on the rail voltage one can reach 100 w with 8 ohm speakers and 200 if 4 ohms are used , with no problems at all .
Any amplifier needs a strong and clean power-supply to be able to output a good bass which implies a relatively high cost for rails between 24 and 50 volts and currents up to between 10 and 20 amps even if it´s only for impulses
Due to all of the above I have successfully built several units with a different concept for the power-supply :
I have used 2 , 3 , and 4 12volt 7Ah AGM-batteries in series ( weight is aprox. 2 kg per battery ) with two parallel capacitors , one of 4700 uF and one 4,7 uF . The internal resistance of one battery is only about 23 mOhms so less than 0.1 ohm for 4 of them and the whole buffered with the two parallel capacitors.
The charging power-supply can be any switched power-supply with an output of 50 watts or more followed by a buck or boost module adjusted to 13.8 volts per battery so 27,6 for two , 41,1 for three.
Disadvange is the weight , advantages are that it is practically noise-free , and extremely high current capacity , cost of about 60 bucks for the whole thing . I obtain the current capacity of a very large transformer-based power-supply ( Which is not a light weight either ) and the stability of an SMPS , and even considerable immunity from power failures .
I love to do unconventional things and I would love a discussion on the subject.
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