Lepai Tripath LP-2020A+ mini Amp dissected

Thanks for posting this information. I bought two of these amps and the imitation Boston Acoustic A40's from parts express to use as computer speakers.

I do get the pop when turning on. Plus there is an annoying hum if you don't have the inputs hooked up to something. Mine came with some huge Vonage , The VOIP company, power supplies. I'll post pics when I get a chance.
 
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Great info, I've already pulled mine apart this morning and will be ordering a few parts. Thanks for the links!
 
Just ordered one of these babies, I'm not much of a modder but I'll certainly look into getting those LEDs less bright. It'll be interesting to see how well it works with a 2 ohm load.
 
Inputs are crossed

If you have the red board check the input terminals. The left channel of the RCA connects to the right channel of the 3.5mm jack and vice versa.
 
I'm really tempted to get one of these amps to drown out the crap music played in our warehouse. I'm tired of the pop station and the 5 songs they play all day everyday.

However I don't have any small speakers, the smallest I have are Polk Monitor 4's and don't have room on my desk for those.
 
Alright, I broke down and bought it on epay. I should get it mid next week. Can you guys recommend any good sounding small speakers to use with this?
 
Lepai LP-2020A+ Tripath Class-T Hi-Fi Audio Mini Amplifier

Hello everyone,

This is my first post but have been reading for quite a while. I have two of these Lepai amps and they are very good for the price. Has anyone had any success in finding a schematic? There are two 4558 Op-amps on the board which are not in the 2020-020 test circuit in the data sheet for the part. These are general purpose dual op-amps and not exactly "audiophile" quality. With no schematic I'm not sure about their function although I suspect they are used as preamps ahead of the 2020 but why two of them? Swapping out to a better amp would most likely improve the sound. Since this is single supply amp I want to make sure how they implemented the op-amps before I do anything.

So primary question is - does anyone know where I can get a schematic?

All the best,
Frank
 
Leipai 2020 Amp

on further thought, the Op-Amps must be for the bass/treble tone control circuit......still would love to have the schematic.

Also, related the the posts on the primary power supply bypass cap, both of my amps are 3,300 uFd 16 Volt. I could get a few caps from Digikey that would fit and raise the value to 6,800 or so.

Frank
 
Has anyone had any success in finding a schematic?

Primary question is - does anyone know where I can get a schematic?
One Redshift187 from diyAudio forum reverse engineered the Lepai's input circuit and posted a schematic. That's where the two 4558 Op-amps are found. The power output section is a standard TA2020 application found on data sheet PDF (just google "TA2020 data sheet").

All credit for drawing up the schematic goes to Redshift187

Full size scan available here

2ahz9mt.jpg
 
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The white light looks a lot better than the blue. Thanks for posting the great pics. I am looking for a small cheap power source for my vintage KLH tuner and the Lepai looks like it would be perfect.
 
I am not crazy about the blue light, but am wondering if there is a quick solution for a non diy'er. Can I simply cut the wires going to the blue lights? which side?

Or for a totally low tech solution, could I simply cover lights with dark nail polish or something similar?
 
I am not crazy about the blue light, but am wondering if there is a quick solution for a non diy'er. Can I simply cut the wires going to the blue lights? which side?

Or for a totally low tech solution, could I simply cover lights with dark nail polish or something similar?

I covered mine with shrink tube...
 
Sooo Lepais finally made it to here :) For a while I thought you guys might be spared that particular Nonsense.
I have 3 lepais And a half dozen ta2020 Chips These are genuinely seductive Once started.
However Tripath collapsed in 2005/6 as did the supply of their Very Good Chips.
There are.. NO More... Genuine Tripath chips, ONLY fakes in varying degree of Crap quality currently available. Supply was exhausted ..Years ago.
ALL the lepais and most all Asian sourced Ta2020 chips/amps are cheap poorly made Fakes. Sad but True.
My 3 lepais , bought sequentially upon the failure of the preceeding one, have died in use after a dozen or so hours running time. First one I thought was due to my incompetence, then 2nd one did exactly the same. Hmmm I thought. Then the 3rd one did as well. ALL had one channel failures. Coincidence.. perhaps??
Yes these can sound surprisingly good,
But despite all the praise/hopes mine did not do very well at all, even fully 'modded' against my years old and faithful He Man Setup.. Not even close actually. Yet, prior to A-B ing I thought it was the equivalent.
Bit of an Epiphany that.
I did say that these contraptions suck one in :)
The mickey mouse circuit used (ain't No tripath evaluation circuit despite bleats to the contrary.. I built one of those.. Which is where My one and only 'Genuine' ta 2020 chip lives :) It's Way better than the Lepai
Note that Lepai Sound Quality Varies.. unit to unit... Mine certainly Did.
PS: I believe Redshift found that Circuit in the DIY Audio forum Lepai Wiki section, as it predates his appearance.
Also DO read that Wiki IF infatuated with these things it's the accumulated knowledge experiences of a Lot of Folks with their lepais, compiled over a few years. Could save a lot of time $ and needless dead ends.
Agreed, it's Great fun modding them, at least until the fake chip dies .
 
Lepai 2020

You are correct in that the reverse engineered schematic varies from the application note - Lepai "cheaped" it up quite a bit. It's not worth swapping out op-amps for something better or anything else. Put your Lepai on a scope with good 8 Ohm loads and look at the high frequency oscillation on the peaks of the sine wave looking like "fuzz" at lower sweep rates. It's not a function of their 2 Amp switching supply either - an analog supply shows the same results. It's far from "audiophile" quality.

Also 20 Watts is a bit of an overstatement - into a resistive 8 Ohm load the Lepai can only output about 8 Watts RMS before clipping. Lowering the load to 4 Ohms doesn't help power output very much either.

It is what it is - a cheap $20 8 watt per channel amplifier. It's frequency response is as stated 20 to 20 KHz +/- 3 dB at full power both channels driven. Just use it until it craps out, replace the 2020 IC or just buy another one.
 
A few comments on this thread:

- That "fuzz" isn't oscillation in the sense of instability. It is the clock frequency inherent in all Class D designs. If you trigger your scope off of the 2020's clock, you will be able to see that the "fuzz" is actually a synchronized waveform.

- I don't think the Lepai chips are fake. Do you know this for sure? That's an expensive chip to clone for an utterly tiny market.

Meanwhile, There were 10's or 100's of thousands of surplus chips around when Tripath folded. (I had several connections to both Tripath and Cirrus.) Lepai is selling maybe a few thousand amps a year. The supply will run out, for sure, but not quite yet.

-All the Tripath chips had serious reliability issues. (Mostly related to supply voltage and sequencing sensitivity.) I've done products with them, and chip failures turned out to be a real problem.

- The 4558 is a good audio amp that is used in many, many pro audio devices. There is no reason to replace it, especially since its performance is orders of magnitude better than the 2020. There couldn't possibly be a (non-imaginary) improvement in sound quality.

-k
 
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Fake!? Absolutely !

Sure some stock was surplus, but C'mon in quantities to supply several production lines even 8 years later ! Don't be thinking that the output is Small Think Tens of thousands not merely thousands
Some Ta2020s say Made in USA Others Say Made in Korea :) Others Have gold plated pins. Did YOU ever see any Gold pinned versions with a very poor imitation of the Tripath logo
On that aspect, each ta chip I've handled has had a 'differing' Tripath logo. No one suggested that these were Good Copies :)
Expensive Chip?
Really? you're making a joke? It's hard to tell from cryptic typed notes.
Ebay sells these Chips from $2 to $5, shipping included ! Far Less if in multiples should one be that naive.
Chinese do Clone, even almost free resistors, let alone IC Chips they can sell for 1$ each.
IF one bothers to research it, all parts on that Lepai board are Chinese copies /relabeled clones . From Caps to the Horrid 'JVC' Opamps they ineptly fit .
I disagree wholeheartedly on your views re that opamp by the way.
The JVC 488 has long proven Excreable in any Audio application... even assuming it's a passable clone.

What makes you think otherwise? that's a truly surprising claim.
Us Audio Weenies are picky re our opamps.
 
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Fake!? Absolutely !

Sure some stock was surplus, but C'mon in quantities to supply several production lines even 8 years later ! Don't be thinking that the output is Small Think Tens of thousands not merely thousands
Some Ta2020s say Made in USA Others Say Made in Korea :) Others Have gold plated pins. Did YOU ever see any Gold pinned versions with a very poor imitation of the Tripath logo
On that aspect, each ta chip I've handled has had a 'differing' Tripath logo. No one suggested that these were Good Copies :)
Expensive Chip?
Really? you're making a joke? It's hard to tell from cryptic typed notes.
Ebay sells these Chips from $2 to $5, shipping included ! Far Less if in multiples should one be that naive.
Chinese do Clone, even almost free resistors, let alone IC Chips they can sell for 1$ each.
IF one bothers to research it, all parts on that Lepai board are Chinese copies /relabeled clones . From Caps to the Horrid 'JVC' Opamps they ineptly fit .
I disagree wholeheartedly on your views re that opamp by the way.
The JVC 488 has long proven Excreable in any Audio application... even assuming it's a passable clone.

What makes you think otherwise? that's a truly surprising claim.
Us Audio Weenies are picky re our opamps.

Uh, the Tripath line moved to Korea at some point, so it is immaterial that the country of origin is different. Further, the original Korean line had (Has?) a license to manufacture the chip. That's NOT a clone. And you are way off on your usage and surplus numbers. My info comes directly from:

1- The Founder of Tripath.
2- The Chief Engineer of Tripath.
3- The CEO of Cirrus, who was my business partner for years.

Obviously, I wasn't discussing the PRICE of the chip, I was discussing the COST of the chip and, in particular, the NRE cost of cloning it. Do you know much about semi-conductor fabrication, and how cloning works? I'm in the biz. I've worked for semiconductor manufacturers. I make audio products in China, and deal with clones all the time. I know who is doing it, how and why.

I've done designs with the 4558 that TAS and Stereophile utterly raved about. I've done month-long controlled listening tests. I understand how opamps and circuits work, and what affects the sound. What are your qualifications to disagree about the 4558? What evidence? Because, frankly, you sound like you don't know what you are talking about, and read too many internet sites. Who needs another highly opinionated, uneducated, so-called audiophile? Not me!

Thank you, drive through.

-k

ps- "He Man Rig" eh? Do you know where, exactly, that term comes from?
 
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Fake!? Absolutely !

Sure some stock was surplus, but C'mon in quantities to supply several production lines even 8 years later ! Don't be thinking that the output is Small Think Tens of thousands not merely thousands
Some Ta2020s say Made in USA Others Say Made in Korea :) Others Have gold plated pins. Did YOU ever see any Gold pinned versions with a very poor imitation of the Tripath logo
On that aspect, each ta chip I've handled has had a 'differing' Tripath logo. No one suggested that these were Good Copies :)
Expensive Chip?
Really? you're making a joke? It's hard to tell from cryptic typed notes.
Ebay sells these Chips from $2 to $5, shipping included ! Far Less if in multiples should one be that naive.
Chinese do Clone, even almost free resistors, let alone IC Chips they can sell for 1$ each.
IF one bothers to research it, all parts on that Lepai board are Chinese copies /relabeled clones . From Caps to the Horrid 'JVC' Opamps they ineptly fit .
I disagree wholeheartedly on your views re that opamp by the way.
The JVC 488 has long proven Excreable in any Audio application... even assuming it's a passable clone.

What makes you think otherwise? that's a truly surprising claim.
Us Audio Weenies are picky re our opamps.

You have no clue who you're disrespecting, do you? Where do you audiophile know-it-alls get your "knowledge"? Sheesh... :rolleyes:
 
You have no clue who you're disrespecting, do you? Where do you audiophile know-it-alls get your "knowledge"? Sheesh... :rolleyes:

Thanks, Chicks! I was originally only trying to add some factual information to the thread. But, it seems like some people are too smart to learn, and too clever to be fooled by the Audio Illuminati....

Bless their oxygen-free tinfoil hats and OPA627 ELF detectors.

-k
 
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