Lepai T-Amp with TA2020

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mannycc

Member
Joined 2008
I bought one but it is not a tripath, it is a TA7240 amp. BUMMER!

It also has a dc offset of more then 60mv and a huge 5 volt burst on switching on!

can someone have a look at this:

http://www.5mv.com/ebay/mini_amp/lpv8/lpv8.jpg

and tell me how to fix this?
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Hi! This may help. Had checked the data sheet and found some caps are not included on your circuit, that might be the problem? IMO the tone control circuit is not a prob. unless gain setting of the opamp is excessive.

Reading the thread, I came accross this lepai thing. Months ago, i have checked and found the chinese websites selling the mosfet amp and i wish to tell you how much it costs, just rmb50, (it's less than usd 8.o at present exchange rate!!). Just recently i had the chance to visit china and asked a chinese friend of mine how to order, unfortunately he has not experienced doing purchases thru internet. I may look for that site again if you have not seen it yet or is interested for info. The amp photos external are also shown not so sure though if it was the right one, but you can see for yourselves.

Rgds.
 
Lostcause

Lostcause

Member
Joined 2005
mannycc said:
Had difficulty looking for this, anyway as mentioned...

http://auction1.taobao.com/auction/item_detail-0db1-62cc3d69bff8bfdc6c694ab78618a33d.jhtml

Something changed, now it seems the amp is powered by 24v used to be 12v only last time i visited the link...

rgds.
Click to expand...

Hi mannycc, you want to buy this one:

TA2024 plug and play PCB

All you need is a cheap box and you are away....

Not the TA2020 of the original Lepai but it looks like a very nice amp;)

I would buy one myself if I could read it!!!:D
 
H

hoka

Member
Joined 2008
mannycc said:
I bought one but it is not a tripath, it is a TA7240 amp. BUMMER!

It also has a dc offset of more then 60mv and a huge 5 volt burst on switching on!

can someone have a look at this:

http://www.5mv.com/ebay/mini_amp/lpv8/lpv8.jpg

and tell me how to fix this?
-------------------------------------------------------------------------------

Hi! This may help. Had checked the data sheet and found some caps are not included on your circuit, that might be the problem? IMO the tone control circuit is not a prob. unless gain setting of the opamp is excessive.

Reading the thread, I came accross this lepai thing. Months ago, i have checked and found the chinese websites selling the mosfet amp and i wish to tell you how much it costs, just rmb50, (it's less than usd 8.o at present exchange rate!!). Just recently i had the chance to visit china and asked a chinese friend of mine how to order, unfortunately he has not experienced doing purchases thru internet. I may look for that site again if you have not seen it yet or is interested for info. The amp photos external are also shown not so sure though if it was the right one, but you can see for yourselves.

Rgds.
Click to expand...

Can you be more specific? I could not find a data sheet and I am kind of a moron at this.
 
M

mannycc

Member
Joined 2008
Can you be more specific? I could not find a data sheet and I am kind of a moron at this.

Hi Hoka,
It should be simple enough, just google the ta7240 or whatever and voila!!


Hi Lostcause,
Consider that to be part of china's mistery just waiting for someone here to unfold! :D Right now i just dont have the confidence to make a china deal, language/system is a real headache but maybe in the future.

Rgds:)
 
R

Rugby13

Member
Joined 2008
Help

I just hooked a Lepai LP-A8 up to my scooter. I have in inline fues of 6amps it is a fast burn fuse when I turn on the amp the fuse blows right away. is 6amps too small or do efinetly have a short? I saw some peolple had and initial power spike on startup would this cause the fuse to blow? Can this be sove with a capacitor at the input?

I'm not realy an electrical guy but I have a soldering iron and I can follow instructions.
 
A

aszu

Member
Joined 2009
They are back!

Those Lepai TA2020 boxes are back on ebay!

Lepai TA2024 auction

Apparently, this is new, improved version ("over 40 changes from their last version the Lepai LP-222A"). I can see it is equipped with proper aluminium knobs, also no more "BOSS" control ;) Can anyone familiar with this design spot some other differences (detailed PCB pictures are included on the auction page)?

Are these boxes still worth buying? I am looking for some cheap and simple amp do drive my Mission 760i speakers. I was thinking about some vintage Marantz/etc amp, but found this thing on ebay and now I am pretty confused because of raving reviews it got everywhere ;)

P.S This is my first post on this forum, hi everybody! :)
 
G

Gmorris

Member
Joined 2005
G

goodgnus

Member
Joined 2009
jalpuna.com
Just out of curiosity - why power it with more than 12v? I ask because I have a 12v radio shack plug already and I assume I can just use it (?). If not, I'll buy a power supply. Radio Shack sells a 13v power supply with noise conditioner... so, if there's really a benefit from using 13v instead of 12v, I might go that route.

Hey, for $25, I can't resist buying one of these Lepai amps! I just bought their TA2020-020 v3. I noticed the previous version of it is on ebay for $19. One easy to spot difference between the models is that the newer one has blue light and the previous had what they call "rainbow". Beyond that, I have no idea, but I bought the newer one just in case.
 
G

Gmorris

Member
Joined 2005
The TA 2020 spec sheet shows 13.5v being the typical input voltage, 14.6v being the maximum and 8.5v the min. The spec sheet shows going from 13.5v to 14.6v will give you 2.5 more watts at 8ohm (0.1% THD+N). Going by these numbers, it would appear that a 12v input would lower your output wattage by 3 or more. I wouldn't normally quibble over a few watts but since these are flea-powered to begin with, I thought I'd go with the 13v. Maybe a 14v would be better but I'm not sure how well regulated these computer power supplies are so I didn't want to get too close to the maximum.
 
G

Gmorris

Member
Joined 2005
Laptops use switch mode power supplies (as far as I know) which are better regulated than the Radio Shack adaptor. The supplies on ebay are also a third of the RS price. The 13v and 14v laptop supplies may have dc jacks that are too large for the lepai amp. The lepai requires a 5.5mm external diameter, 2.5 internal diameter jack.

The new board appears to be of a higher quality than the photos posted earlier in this thread.

The old version had the chip sinked to the case while the new version has a heatsink attached to the chip. The new version also appears to have larger resistors (higher power rating), higher quality capacitors in some areas, and is missing some diodes. The opamp has a few small caps (by-pass?) added around it too.

Old version (from page 2 or 3 of this thread):
 

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A

aszu

Member
Joined 2009
New version indeed does look better than the old one ;)

My only concern is this generic, crappy op-amp (JRC stuff). This element seems not to be present in the other T-amps (SI, TA 10, AMP etc). Why Lepai design has it?

How do you think, what impact on a sound quality does it have? Is it worth trying to swap it out (possibly to LM4562NA?) or bypass it completely?
 
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