That "one chip" is the main part of the amplifier, so probably they have nothing in common except the horrible case and the back connectors layout… the circuit inside will be different.
Also the chip in that is a class B amplifier TDA8566 pdf, TDA8566 description, TDA8566 datasheets, TDA8566 view ::: ALLDATASHEET :::, not the class D type…
I got it today. The box said TA2020 but it's labelled as 'BOSE' so what chip and circuit it actually has I do not have a clue.
I plugged my laptop into it and hooked it up to some vintage Wharfdale speakers. It sounds pretty good! It will be more than good enough for what I want tit for. I only want to power some passive monitors in our make shift studio.
I plugged my laptop into it and hooked it up to some vintage Wharfdale speakers. It sounds pretty good! It will be more than good enough for what I want tit for. I only want to power some passive monitors in our make shift studio.
more info
Open the box, it is simple. Take a picture of the board & post it here. Lets see if there is a tripath chip in there.
Open the box, it is simple. Take a picture of the board & post it here. Lets see if there is a tripath chip in there.
Almost all op amps require a +/- power supply... but that is easily accomplished with a simple voltage divider and a floating ground.
The case is not the point.
This little amp punches way above what it costs, but has caveatss in addition to its low power:
1. Power input must be <14V for TA2020 Tripath chip. This limits output power to about 15WPC at 4 ohms load, 10 WPC at 8 ohms.
2. The usual provided PS is 12 VDC 2A switching, regulation quality uncertain. Higher amperage supplies will provide slightly greater output power at 4 ohms. Good regulation is important.
3. Strongly recommend NOT sourcing this amp from E-bay. Parts Express sells same for slightly more $$, but infant mortality on this amp far from unknown, and PE has rapid and superb service after sale. Also, there are several versions and PE always provides the latest and best in stock. I suspect the PS they supply is also better.
4. This little amp does remarkably well with some speakers that sound very mediocre or lousy driven by common class AB amps.
5. The TA2020 speaker outputs are 'floating', and this therefore cannot be wired up in the usual way as a headphone amp. Isolated common lead to headphone common negative lead is necessary for this application.
6. Yes, it is possible to 'mod' this amp to improve sound quality, but IMHO it makes more sense to apply $$ to purchase of higher power/higher quality additional amp board. Most modders do this for fun, however, and the Lepai makes for a very inexpensive test bed for those wishing to experiment with the TA2020.
7. It is often useful to boost input signal to various of these class D amps to get more output. Also I note that these amps (at least to my aged ears) degrade listening quality more gradually when driven near clipping than most of the AB amps I have known. 10% HD from a T-amp sounds to me somewhat better than similar from an AB. Of course, once driven into hard clipping they ALL sound AWFUL and can damage your speakers if left in this condition for more than a second or two.
This little amp punches way above what it costs, but has caveatss in addition to its low power:
1. Power input must be <14V for TA2020 Tripath chip. This limits output power to about 15WPC at 4 ohms load, 10 WPC at 8 ohms.
2. The usual provided PS is 12 VDC 2A switching, regulation quality uncertain. Higher amperage supplies will provide slightly greater output power at 4 ohms. Good regulation is important.
3. Strongly recommend NOT sourcing this amp from E-bay. Parts Express sells same for slightly more $$, but infant mortality on this amp far from unknown, and PE has rapid and superb service after sale. Also, there are several versions and PE always provides the latest and best in stock. I suspect the PS they supply is also better.
4. This little amp does remarkably well with some speakers that sound very mediocre or lousy driven by common class AB amps.
5. The TA2020 speaker outputs are 'floating', and this therefore cannot be wired up in the usual way as a headphone amp. Isolated common lead to headphone common negative lead is necessary for this application.
6. Yes, it is possible to 'mod' this amp to improve sound quality, but IMHO it makes more sense to apply $$ to purchase of higher power/higher quality additional amp board. Most modders do this for fun, however, and the Lepai makes for a very inexpensive test bed for those wishing to experiment with the TA2020.
7. It is often useful to boost input signal to various of these class D amps to get more output. Also I note that these amps (at least to my aged ears) degrade listening quality more gradually when driven near clipping than most of the AB amps I have known. 10% HD from a T-amp sounds to me somewhat better than similar from an AB. Of course, once driven into hard clipping they ALL sound AWFUL and can damage your speakers if left in this condition for more than a second or two.
Would I dare to connect these carspeakers to it ? in order to make some sort of portable speaker ?
Aura 5000RPM 5-1/4" 2-way Component Speaker Pair 269-180
Aura 5000RPM 5-1/4" 2-way Component Speaker Pair 269-180
You could try, as they are 4 ohm and 91 db you'll get good Volume with this amp, but using car speakers has the disadvantage of not having the complete specs to build an appropriate enclosure...
Make sure you don't run the amp to its limits. Otherwise you will blow the tweeters if it starts distortion
Just received my uber-cheap ebay Lepai LP2020.
Despite the cheap price, and a few faults I've noticed, the sound has whetted my appetite for T-class amps enough to seriously consider putting together a multi-channel monoblock using Arjen's TK2050 monoblock modules. I have bought a TEAC 2050-based Tripath amp which I'm looking forward to.
Few things I've noticed about this unit.
1) The volume control is a bit odd. Room-filling sound only really starts to be achieved with the volume around the 2pm mark, more than I would have liked. Is this normal, and what levels are likely to damage the unit?
2) There is a slight noise coming from the right output -- it's there even without the input connected and does not increase as the volume is turned up. I'd imagine this is power related -- it does sound like a clipped rendition of a 50Hz sine wave.
3) What is the score with the tone controls? I get a reasonably flat response with the pots around half-way, but it isn't quite there. I've noticed that some people replace these, however I'd like to be able to bypass them completely (this particular unit lacks a bypass control). Is there an instruction anywhere on how to achieve this?
Despite all this, this is a cracking little amp for the money. Although it seems to be a little lacking in dynamic range, the detail does definitely have something of the valve sound about it. I've only tried it with a cheap set of budget bookshelf speakers so far, but it's already apparent that this amp has my old AMC 3000-series beaten in some respects. Not bad for £12 delivered from China, and that included what claims to be a 12V/5A PSU as well (hmmm, I'll need to check that as well as it also calls itself a "Toshiba", made by "Delta", and I'm not convinced lol).
Despite the cheap price, and a few faults I've noticed, the sound has whetted my appetite for T-class amps enough to seriously consider putting together a multi-channel monoblock using Arjen's TK2050 monoblock modules. I have bought a TEAC 2050-based Tripath amp which I'm looking forward to.
Few things I've noticed about this unit.
1) The volume control is a bit odd. Room-filling sound only really starts to be achieved with the volume around the 2pm mark, more than I would have liked. Is this normal, and what levels are likely to damage the unit?
2) There is a slight noise coming from the right output -- it's there even without the input connected and does not increase as the volume is turned up. I'd imagine this is power related -- it does sound like a clipped rendition of a 50Hz sine wave.
3) What is the score with the tone controls? I get a reasonably flat response with the pots around half-way, but it isn't quite there. I've noticed that some people replace these, however I'd like to be able to bypass them completely (this particular unit lacks a bypass control). Is there an instruction anywhere on how to achieve this?
Despite all this, this is a cracking little amp for the money. Although it seems to be a little lacking in dynamic range, the detail does definitely have something of the valve sound about it. I've only tried it with a cheap set of budget bookshelf speakers so far, but it's already apparent that this amp has my old AMC 3000-series beaten in some respects. Not bad for £12 delivered from China, and that included what claims to be a 12V/5A PSU as well (hmmm, I'll need to check that as well as it also calls itself a "Toshiba", made by "Delta", and I'm not convinced lol).
No output? Check your signal source on another amp, if possible. Also, try a different 12V power supply. There is no output relay on this unit...what you may be hearing is the protection kicking in because the power supply has lost regulation.
Noise in 1 channel could indeed be the power supply, which sounds from the labeling like a cheap knock off. More than 3A is not needed. Radio Shack has a 12V 2.5A wall wart that in my experience has good regulation. Try that.
Noise in 1 channel could indeed be the power supply, which sounds from the labeling like a cheap knock off. More than 3A is not needed. Radio Shack has a 12V 2.5A wall wart that in my experience has good regulation. Try that.
Thanks Stu for that, and the heads-up that a 2.5A supply will be sufficient (at least for testing).
I swapped the supply for one intended for a small Juniper Networks firewall (2.5A) and the amp is now deathly quiet. Seems to have further improved the sound slightly as well, the bass seems more extended than before. So win-win
So yeah, the cheap knock-off power supply isn't that great, although it'll have its uses for something else I'm sure (monitor power etc).
I swapped the supply for one intended for a small Juniper Networks firewall (2.5A) and the amp is now deathly quiet. Seems to have further improved the sound slightly as well, the bass seems more extended than before. So win-win
So yeah, the cheap knock-off power supply isn't that great, although it'll have its uses for something else I'm sure (monitor power etc).
I would worry first for damaging the speakers, when the unit overloads the Tamp output at high freq is unstable and could damage the speakers. Anyway, you will notice a very bad sound when the amp starts clipping, in that case turn down the volume.
There is a pin to drive an overload indicator, but isn't used on the Lepai, I have tried to add a LED, but as said before, is really easy to recognize when the amp stars overloading because of the bad sound that outputs.
Is explained in the thread, but you could try to have a look at the wiki Amplifier:Lepai T Amp - diyAudio and when you know what version of the board you have we can help you with bypass.
Don't think so, but it is not the best option, the Lepai has a built in protection that drops the voltage to 13.5v but people say that with an input higher than that 13.5v the sound is worse because of the protection. I would try to get a lower voltage psu (try first yours with a volt meter, because often, the output differs slightly from specs).
Thanks -- I've not noticed any hard-clipping from the amplifier (the speakers I'm using are 8R so should in theory be easier to drive anyway).
I think my unit is a 2020B (it has a speaker relay but no tone bypass switch) although it's labelled as a 2020A+ so I'll pull it to bits today and see what the score is, and hopefully follow those instructions.
I think my unit is a 2020B (it has a speaker relay but no tone bypass switch) although it's labelled as a 2020A+ so I'll pull it to bits today and see what the score is, and hopefully follow those instructions.
Having examined the schematic, as well as the TA2020 datasheet, it is clear that the power supply quality is important in terms of the ultimate results. Also, I observe that the power supply provided with the Lepai amp varies from vendor to vendor. The supply provided by Parts Express appears to be of better quality than most. However, it is still 12V at 2A, slightly limiting the power output of the amp.
The TA2020 datasheet states that 14.5VDC is the highest recommended PS voltage for the chip. Since the amplifier can produce up to 20W RMS into 4 ohms per channel, in order to get the most from both channels driven, a linear regulated PS of 12-13VDC capable of 4A would yield maximum sustainable results from this design. This could be achieved using a 12-0-12V 3-4A power transformer, connecting the 12V leads together and the center tap as ground, into a bridge rectifier and linear regulator circuit. There are several simple linear regulator circuits for 3-5A output, including 3-5 7812 regulator chips in parallel with their outputs connected via 0.1 ohm ballast resistors, or a single 7812 with a parallel bypass transistor. I suspect a computer switching power supply would work nicely, also, since these provide up to 20 or so A output on the 12V rail with pretty good regulation (usually output voltage between 11.8 and 12.2V measured under varying load). As used computer power supply is likely the least expensive option, since these change hands for $15 or so. However, older ATX supplies can have high frequency switching noise in the DC, so some sort of outboard filter might be needed for good results. Worthy of experimentation; I will do some if I can get up the energy....
The TA2020 datasheet states that 14.5VDC is the highest recommended PS voltage for the chip. Since the amplifier can produce up to 20W RMS into 4 ohms per channel, in order to get the most from both channels driven, a linear regulated PS of 12-13VDC capable of 4A would yield maximum sustainable results from this design. This could be achieved using a 12-0-12V 3-4A power transformer, connecting the 12V leads together and the center tap as ground, into a bridge rectifier and linear regulator circuit. There are several simple linear regulator circuits for 3-5A output, including 3-5 7812 regulator chips in parallel with their outputs connected via 0.1 ohm ballast resistors, or a single 7812 with a parallel bypass transistor. I suspect a computer switching power supply would work nicely, also, since these provide up to 20 or so A output on the 12V rail with pretty good regulation (usually output voltage between 11.8 and 12.2V measured under varying load). As used computer power supply is likely the least expensive option, since these change hands for $15 or so. However, older ATX supplies can have high frequency switching noise in the DC, so some sort of outboard filter might be needed for good results. Worthy of experimentation; I will do some if I can get up the energy....
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