Dear people,
I'm looking for (build in) pre amplifier for a LM3886 chip amp, see pictures below. The amp is powersupplied by a Toroidal Transformer 230v - 2 x 25v 6A. The amp sounds nice but I miss bass and power.
Anyway, I ordered this pre amp board by Dollatek. It fits the 47K Ohm values the amp needs. But now I need a dual 12v up tp 20v AC psu/transformer/voltage regulator. Can anybody advice me? Can I branche power for the toroidal? Do I need a second smaller transformer? I worry about possible hum.
I'm looking for (build in) pre amplifier for a LM3886 chip amp, see pictures below. The amp is powersupplied by a Toroidal Transformer 230v - 2 x 25v 6A. The amp sounds nice but I miss bass and power.
Anyway, I ordered this pre amp board by Dollatek. It fits the 47K Ohm values the amp needs. But now I need a dual 12v up tp 20v AC psu/transformer/voltage regulator. Can anybody advice me? Can I branche power for the toroidal? Do I need a second smaller transformer? I worry about possible hum.
Why not use a pair of voltage regulators, to give you +-15volts from the amplifier boards main smoothing capacitors?
If the amplifier voltage is less than +-35volts an L7815ACV and L7915ACV will work from that voltage giving you +-15 volts required to run the preamp ICs.
The +- voltage can be connected directly to the AC input connector with the ground in the centre. It doesn't matter which way around they connect, the bridge rectifier will take care of the polarity.
I would place the regulators on small heatsinks if only for aesthetics as they won't run hot.
Don't forget decoupling capacitors mount a pair of 10uF capacitors on the ground pin up to the input and output of each regulator.
If the amplifier voltage is less than +-35volts an L7815ACV and L7915ACV will work from that voltage giving you +-15 volts required to run the preamp ICs.
The +- voltage can be connected directly to the AC input connector with the ground in the centre. It doesn't matter which way around they connect, the bridge rectifier will take care of the polarity.
I would place the regulators on small heatsinks if only for aesthetics as they won't run hot.
Don't forget decoupling capacitors mount a pair of 10uF capacitors on the ground pin up to the input and output of each regulator.