Max supply voltage is ±32 V, which leads to a maximum output voltage of ~19V AC.CJ900RR said:
According to the datasheet 1/4 W is enough. Rule of thumb is to use resistors with 100 % safety margin, so we can only load it with 1/8 W. 4,7 Ohm needs 0,5875 V for that. The impedance of the 100 nF capacitor would have to be lower than 147,3 Ohm to achieve that voltage drop across Rsn. That is the case above ~10800 Hz. Is the supply voltage ±32 V? And if so, what could lead to continuous nominal output at 10800 Hz or above?
With 2,7 Ohm it takes 1,64 V to reach 1 W. With max supply voltage of ±38 V you get ~24 V AC out. The impedance of the 100 nF capacitor needs to fall below 36,8 Ohm for 1,64 V across the resistor. That is the case above ~43200 Hz. Sound like serious oscillation.Dxvideo said:
Rsn should be 1/4 W as per datasheet. If it burns, find out why and fix the fault.
The TDA7294 is designed for use with a split power supply. A battery is a single power supply.ballsingtripp said:
The most promising amps for use with a 12 V battery are the ones designed for cars. E. g. µPC2505 for a single channel, TDA7374 or TDA8560 for two channels, TDA7560 for four channels. These are internally bridged amplifers already, so you cannot bridge them any further. There a numerous similar ICs and you will have to choose according to availability and desired output power.ballsingtripp said:
An alternative could be a T-amp, that also come designed for 14,4 V single supplies (car battery!). They even have the advantage of being very efficient, so your battery will serve for longer listening sessions without recharging.
pacificblue said:
Would the TDA8560 work for an 8 ohm load? Not much info in the data sheet, and it just says 2-4.
The T-amps look nice, but a bit too expensive for this project.
I think it would be possible to use 4 TDA2040's, two per channel bridged, for about 12 W. Their minimum supply voltage is ±2.5V, but I have no idea how it would sound.
Attachments
that tda schematic shows a bridged amplifier.
Pacific has already told you that you cannot bridge it again.
It also shows +-16V (=32V) supply for 30W into 8r0 @ 0.5% distortion.
If you reduce the supply to 13.8V (for a charging battery supply) the power will drop to around 6W and still with that terrible 0.5% distortion.
Pacific has already told you that you cannot bridge it again.
It also shows +-16V (=32V) supply for 30W into 8r0 @ 0.5% distortion.
If you reduce the supply to 13.8V (for a charging battery supply) the power will drop to around 6W and still with that terrible 0.5% distortion.
The TDA2040 isn't internally bridged. I'm not bridging it again, that schematic just shows two (it's a 1ch amp) as an alternative to the SE circuit.
I assumed it would be around 12W bridged with a 12V supply, since it would be about 6W single ended (according to the datasheet).
I know the distortion is pretty high, but it's the only chip I can find so far that I could bridge for over 10W with a 12V supply.
I guess it isn't possible anyway since it wouldn't be a split supply.
I assumed it would be around 12W bridged with a 12V supply, since it would be about 6W single ended (according to the datasheet).
I know the distortion is pretty high, but it's the only chip I can find so far that I could bridge for over 10W with a 12V supply.
I guess it isn't possible anyway since it wouldn't be a split supply.
1/4 W will be sufficient.ballsingtripp said:
Turning electronic devices on and off is always stressing the components and reducing their life expextancy more than many hours of work. This amplifier also has a turn-on delay, which you would have to wait for, each time you cycle the power.ballsingtripp said:
The stand-by switch is a possiblilty to reduce the output by 90 dB without actually switching the amplifier off. The power consumption is reduced and there will be as good as no music output.
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