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Old 30th April 2010, 02:08 AM   #551
troystg is offline troystg  United States
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Quote:
Originally Posted by cyteen View Post
Actually your early for the next party. The 838 doesn't use the tripath 2020 chip and so is unrelated to this thread. It may use Sanyo (LA4625) Toshiba (7240) ics so also not for the Class D section.
Really..

Then please excuse the interruption and continue with your discussion. I will show my self out.
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Old 1st May 2010, 10:36 AM   #552
raz is offline raz  Sweden
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Hi, i have bought 3 Lepai TA2020 amps and they have all broke .
I have hooked them up to a car battery some 4ohm speakers and a mp3player. It all sounds great until I turn up the volume and the amp breaks. After that all i get out of it are some clicking sounds and the led light.

Since there are no fuse i have no idea what's broken inside. Have anyone encountered the same problem? is it fixable? or should I just buy yet a new one?

Thanks.
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Old 1st May 2010, 10:48 PM   #553
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Default Lepai 2020 clicking

I see I'm not the first with this problem. My amp worked well for a few days and then began to click repeatedly. I'm up to speed with old technology (vacuum tubes!!), but not sure where to begin with this thing.

Is it likely that the chip is burned or is there some way to reset the protection devices and give it another try?

Any advice appreciated.
Cary, NC
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Old 1st May 2010, 11:50 PM   #554
Pano is offline Pano  United States
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Clicking on a Tripath chip usually indicates a short circuit. Actually an "over current" fault. But I can't think how this would come on by itself. Worth a check, tho.

Dead chips mostly don't make any noise at all.
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Old 1st May 2010, 11:58 PM   #555
vzon is offline vzon  United States
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Default Ultra capacitors

Quote:
Originally Posted by vzon View Post
I have been using the LApai amps for a several months now and really like them. I first had one and then got a second one. I have them hooked to my computer , one is the main front left right channels and the other is for the subwoofer channel.

I made a power supply by using an 8 amp switching supply and hooked that to three large 1 farad stiffening capacitors that are normally used in auto sound systems and it works very good. I can get floor rumbling bass out of the amp.

I have found that just one of the bigexterior stiffening capacitors was not enough as when I turned the volume up the voltage wolud drop on the digital readout. When I hoooked three up together and had an 8 amp power supply it could hold the voltage steady even at loud volumes.

Just recently blew the main amp out and have ordered two more. I plan on doing some modifications to it like I have read on the forum here, probably starting with the input caps.

So after all that I have also been looking into Ultra capacitors. with a few of these one could get up a farad or more worth of capacitors inside the lepai case, What you can do to start is hook three of the 5.5 volt 1 farad ultra capacitor in series so they can handle 16.5 volts max, which wolud be fine for a 12 volt system. With just three of them you could have about 330,000 uf worth of capacitor inside the case of the lapia 2020.
Each of them is only 3/4 inches in diameter and about 1/4 inch thick.
thats all for now. If any one wants photos let me know.
I just installed the ultra capacitors in my amp, and here is a picture.
total capacitance is 333,333uf
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Old 2nd May 2010, 03:06 PM   #556
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Panomaniac - thanks for the reply! Actually was using the amp doing some speaker testing with my PC and Clio - was running a response curve on the amp to try to determine the flattest settings for the tone control (which I managed to do before it blinked out on me).
After a short rest with the power unplugged, the amp is working fine now again! I'll try to publish the response curves here for all to see if it's permitted to do so.

My amp gets pretty flat with treble and bass around 1:00 on the dial, but they may vary. Even so, you can't get a ruler flat response with the circuit - there are abberrations of a dB or so in midband and very high frequencies. So a tone defeat might make sense if you are using the amp for testing like I do.
thanks again!
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Old 2nd May 2010, 03:11 PM   #557
Pano is offline Pano  United States
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You're welcome. And thanks for checking the tone controls. Useful info.

The chips will reset if overloaded or overheated. A power down often does it.
Of course if the short circuit still exists, you'll have to fix it!
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Old 2nd May 2010, 05:15 PM   #558
raz is offline raz  Sweden
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Hmm.. Well i have tryed to just unplug the power for a while but two of the amps just keep clicking and the other is just quiet. Are they dead? i just seams wired that you can kill them that easy by just turning up the volume.

or if its a short, what would short out by turning up the volume ? can i fix it?

vzon, are u saying that i should replace the capacitance? wont that just make it even more likely to blow the amp?
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Old 3rd May 2010, 02:55 AM   #559
vzon is offline vzon  United States
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Quote:
Originally Posted by raz View Post
Hmm.. Well i have tryed to just unplug the power for a while but two of the amps just keep clicking and the other is just quiet. Are they dead? i just seams wired that you can kill them that easy by just turning up the volume.

or if its a short, what would short out by turning up the volume ? can i fix it?

vzon, are u saying that i should replace the capacitance? wont that just make it even more likely to blow the amp?

No I was just sharing info an adding capacitors. not as a remedy for your non working ones. I had one of my amps blow also a couple weeks ago. I think its just from puttting in to strong of a signal in some cases.
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Old 3rd May 2010, 10:48 AM   #560
col is offline col  Australia
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The Lepai TA2020 may be a humble implementation of the Tripath TA2020 but the chip was ground breaking:

25 Microchips That Shook The World

IEEE Spectrum: 25 Microchips That Shook the World

Tripath Technology TA2020 AudioAmplifier (1998)

There’s a subset of audiophiles who insist that vacuum tube–based amplifiers produce the best sound and always will. So when some in the audio community claimed that a solid-state class-D amp concocted by a Silicon Valley company called Tripath Technology delivered sound as warm and vibrant as tube amps, it was a big deal. Tripath’s trick was to use a 50-megahertz sampling system to drive the amplifier. The company boasted that its TA2020 performed better and cost much less than any comparable solid-state amp. To show off the chip at trade shows, ”we’d play that song--that very romantic one from Titanic ,” says Adya Tripathi, Tripath’s founder. Like most class-D amps, the 2020 was very power efficient; it didn’t require a heat sink and could use a compact package. Tripath’s low-end, 15-watt version of the TA2020 sold for US $3 and was used in boom boxes and ministereos. Other versions--the most powerful had a 1000-W output--were used in home theaters, high-end audio systems, and TV sets by Sony, Sharp, Toshiba, and others. Eventually, the big semiconductor companies caught up, creating similar chips and sending Tripath into oblivion. Its chips, however, developed a devoted cult following. Audio-amp kits and products based on the TA2020 are still available from such companies as 41 Hz Audio, Sure Electronics, and Winsome Labs.

++++++++

Class-T has every right to be under the Class-D section of this forum.

If you need a clear definition read the wikipedia page

Class T amplifier - Wikipedia, the free encyclopedia

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