Guys
I have this transfomer ,, I want to use it with my transistor amplifier c5198 A1941 or c5200 a1943
My transfomer is 28 0 28 1.3A =72.8VA
My question is ..is that 72 watts or VA
If it's VA then we have to multiply it by 0.8 and then we get 57.6w which is usable power
Then class AB efficiency is only 50 to 70%
Let's assume 65% then we get 37w
Am I right with the calculation?
Then wat if I'll be using 24 0 24 5A transfoma how much power can I get with one channel (mono) or stereo or stereo and one extra channel for bass pls help
I have this transfomer ,, I want to use it with my transistor amplifier c5198 A1941 or c5200 a1943
My transfomer is 28 0 28 1.3A =72.8VA
My question is ..is that 72 watts or VA
If it's VA then we have to multiply it by 0.8 and then we get 57.6w which is usable power
Then class AB efficiency is only 50 to 70%
Let's assume 65% then we get 37w
Am I right with the calculation?
Then wat if I'll be using 24 0 24 5A transfoma how much power can I get with one channel (mono) or stereo or stereo and one extra channel for bass pls help
1.3A is very little. Especially for 4 Ohm.
It does not matter we have 28-0-28 Volt.
It does not matter we have 28-0-28 Volt.
Yes.
imagine a 72 VA transformer providing 1 V and 72 A. You cannot use all the current capability because of limited voltage.
In your case all the voltage is "useless" because of current limit.
You transformer is simply not made for an amp driving a 4 ohm speaker.
Try 16 ohm speakers instead: 27 W!
The power output will depend on:
1. Secondary voltage
2. Speaker impedance
3. Amplifier class of operation
4. Current capability of the power supply (which in turn depends on the transformer VA, rectification, and capacitance storage)
5. Current capability of the amplifier output stage
6. Amplifier gain
7. Input voltage
In your case, build an AB class amplifier with approximately 22,000 μF of capacitance per voltage rail. That will give you a fair amount of dynamic power, and the perceived power will be sufficient for all your needs. Choose 8-ohm speakers if you can... but the 4-ohm speakers will do the job, especially if efficient (around 88dB/1W at 1m... or better).
Then, one day... just replace the transformer with something better (min 300VA). Therefore, when choosing the bridge rectification and capacitor storage today, keep in mind not to go below a 50V nominal capacitor voltage... I'd go with 63V. Pick a nice bridge rectifier puck(s) - 400V/20A or better, and leave some space for a bigger transformer. Like this, you'll have 30-40W dynamic power at 8 ohms today, and once you upgrade the transformer, you'll get close to 100W at 8 ohms.
1. Secondary voltage
2. Speaker impedance
3. Amplifier class of operation
4. Current capability of the power supply (which in turn depends on the transformer VA, rectification, and capacitance storage)
5. Current capability of the amplifier output stage
6. Amplifier gain
7. Input voltage
In your case, build an AB class amplifier with approximately 22,000 μF of capacitance per voltage rail. That will give you a fair amount of dynamic power, and the perceived power will be sufficient for all your needs. Choose 8-ohm speakers if you can... but the 4-ohm speakers will do the job, especially if efficient (around 88dB/1W at 1m... or better).
Then, one day... just replace the transformer with something better (min 300VA). Therefore, when choosing the bridge rectification and capacitor storage today, keep in mind not to go below a 50V nominal capacitor voltage... I'd go with 63V. Pick a nice bridge rectifier puck(s) - 400V/20A or better, and leave some space for a bigger transformer. Like this, you'll have 30-40W dynamic power at 8 ohms today, and once you upgrade the transformer, you'll get close to 100W at 8 ohms.
You want the power supply impedance to match the load impedance roughly. So if an 8 ohm load and the supply is 28V you want about 3.5A from it to handle the peaks. However there are complications - the filter caps can smooth over the load current from the perspective of the supply, and you'll never see the full power supply voltage across the load due to losses in the output devices etc, so perhaps only 24V / 3A peak is needed. With filter caps smoothing this perhaps only 1A per winding on average are needed (56W in, and the load takes 36W)
Also you have to derate the transformer as its not a resistive load, whether 72VA can provide the full 56W in this scenario is best checked by simulation, and plotting the I-squared-R losses in the transformer compared to 72VA with resistive load.
Also you have to derate the transformer as its not a resistive load, whether 72VA can provide the full 56W in this scenario is best checked by simulation, and plotting the I-squared-R losses in the transformer compared to 72VA with resistive load.
Thanx,, I thought I will get 40w at 4ohms
Am having 12inch sub 4ohms 300w rms 1200w peak