| Opie |
How large of a power supply would I need for the TA2020, it's 2 x 20 watts rms. I am going to use a supply with 12.5 volt DC rails.
How large of filter capacitors would I need.
Brian |
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| subwo1 |
I would look at the problem in terms of the speaker load. If you use 8 ohm speakers, then the peak current per channel is 12/8=1.5. So for two channels you could use a 3 amp power supply. Since the chip uses BTL, bridge tied load, outputs the peak to peak output voltage can reach twice the supply voltage, or 24 volts. But the load doesn't see more that the peak voltage at any moment in time, if the inductive kick of the speaker is neglected.
For filter caps, 4700microF is often used for 8 ohm loads, and if you use a 6amp supply for 4ohm loads, then 10000microF is fairly standard. I tend not to use ones not quite so large myself. |
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| Opie |
Would I be able to use a regulated power supply for this amp rated at 6 amp, for a 4ohm load or are there some disadvantages to using a regulated supply?
Thanks,
Brian |
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| subwo1 |
| Actually, I think it would do better with a regulatd supply. Switching amplifiers tend to pass the charasticis of the power supply to the load since they are literally connecting the load to the power supply rails for varying lengths of time. So, for example, if the power supply sags, the output level does the same. |
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| Opie |
subwo1,
I found a regulated power supply from a CB radio that I had in the basement. I tested the output voltage and it was 13.8 volts DC.
Is this too high for this amplifier?
Thanks again,
Brian |
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| subwo1 |
| Brian, I checked the data sheet for the TA2020 and it says the max voltage is 14.5v. So 13.8v is fine. When I figured the power needs for the chip, I was only doing one channel. The peak current draw would actually be 3*2=6amps. Sorry about the oversite. Is the power supply only a 3 amp one? |
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| Opie |
No, the power supply is rated at 20 amp continuous, so this will be plenty of power!
Brian |
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| Opie |
Was that power figure for an 8ohm load or 4ohm?
Brian |
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| subwo1 |
| Yes, great. The calculation was for an 8ohm load. For 4ohm, figure on twice as much or 12amp total. I don't see any problem at all! |
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