TA2020 Power Supply

[Carlp]

I bought a TA2020 based amp on the Bay (cheap!) to try out Class T (I'm a Class T-uber normally) that requires a 14-15vdc supply at around 5 amp capacity. I have a wall wart-style PS (from a laptop) that puts out 16.9vdc with a 5+amp capacity and I wonder what you all think about using it for the 2020. If it's a reasonable idea, what's the best way to drop the voltage about 2V?

If not, I might be able to come up with a PS design using a voltage regulator, but if anyone has a recommended PS for me to look at, I'd be grateful.

Thanks.
Carlp

[DigitalJunkie]

The simplest method would be to put a few diodes in series on the power lead to the amp. Each one will drop approx 0.7V,so 3-4 diodes would be needed.They will get a bit warm,but not much. I can't think of any 6A diode PN's off the top of my head though.

[Carlp]

Interesting idea. Thanks. I happen to have some MR751 Fast Recovery diodes. These are rated 100V, 6A and have a forward voltage drop (max) of .9v. Should work? Please let me know if this isn't a good idea.

Carl

[gervasius]

I also bought cheap TA2020 (Lepai ) froom ebay as a tryout with this kind of amp, and it was without power supply. I connected it to a supply from creative speakers which seamed like a good choice since it's rated to 12V and 4.2A and is quite heavy. I even didn't have to change the connector. But to no avail, the amp burnt when plugged, so I need advice on what went wrong. I had one speaker connected, and have no confirmation that the power supply is in working order (bought it on the market). I would like to try with another amp, but want to avoid this happening again. The amp produced crackling and distorted sound on 12V/1.25A power supply before.

[theAnonymous1]

Originally Posted by gervasius

I connected it to a supply from creative speakers which seamed like a good choice since it's rated to 12V and 4.2A and is quite heavy.

If it's heavy, it's most likely an unregulated standard transformer. These have a much higher voltage unloaded than they have with their rated loading.

It's not "12V and 4.2A", it's "12V @ 4.2A". This means that with current draw of 4.2A the voltage will be ~12V. Unloaded the voltage is probably >16V.

[Minion]

Originally Posted by gervasius

I also bought cheap TA2020 (Lepai ) froom ebay as a tryout with this kind of amp, and it was without power supply. I connected it to a supply from creative speakers which seamed like a good choice since it's rated to 12V and 4.2A and is quite heavy. I even didn't have to change the connector. But to no avail, the amp burnt when plugged, so I need advice on what went wrong. I had one speaker connected, and have no confirmation that the power supply is in working order (bought it on the market). I would like to try with another amp, but want to avoid this happening again. The amp produced crackling and distorted sound on 12V/1.25A power supply before.

Did you make sure the Polarity was correct and are you sure it is a DC supply ??

[theAnonymous1]

Originally Posted by Minion

...are you sure it is a DC supply ??

Bingo.

I was just googling "12V 4.2A" creative power supply, and it looks like they are indeed AC output.