Modding the Lepai T2020A+

[RINNAV]

Re: Modding the Lepai T2020A+

In my attached pic you can see the caps that mine came with in that position. This is what the datasheet says about them, "AC input coupling capacitor which, in conjunction with RI, forms a highpass filter at". And the datasheet value is 2.2 as the ones in mone are.

And for somebody that might be in the know? The ones in mine are "Nichicon muse" or at least market as that. So would this mean that they are actually good quality and that theres no point in replacing them?

I used Muse caps on my line-level pre amplifier and love them... They are not too expensive (all things considered) and seem to be quality caps but there are others that fall into this category also. You could replace them but I doubt it would be worth the trouble. I won't comment on "sonics”--that will likely turn this thread into a flame pit...

[duanebro]

Re: Modding the Lepai T2020A+

FWIW: My amp just came in today. The included PS is 13.5V 2A. I have not opened it up yet, but I wonder if they have changed it to handle the higher voltage.

[XtremeRevolution]

Re: Modding the Lepai T2020A+

FWIW: My amp just came in today. The included PS is 13.5V 2A. I have not opened it up yet, but I wonder if they have changed it to handle the higher voltage.

That is quite interesting. Let me know how it runs. They may have updated the design. Is the model number still T2020A+?

[blossom]

Re: Modding the Lepai T2020A+

Heres how i got on so far, Panasonic fc caps, thats about as good as I could get easily here(AU), 6600 total for the power. I might still look into some film caps at signal input. Plus the output stage is not the same as the datasheet, might try and get that back to whats advised too. As can be seen I scraped the tone section. Has been fun.

[bare]

Re: Modding the Lepai T2020A+

Help??
Today did All the mods in Post # 1 Kudos to whomever thought these up.. they Work 'Fine' !! Mine is the Red PCB version .. latest one?
Except I used Polyester Film & foil 2,2 ufs for C20/21 (same location as those green things in above posings .. Had to use wires and Foamy taped the pair on,over by the Opamps, the case fits.
Did not swap out Inductors as I couldn't get any locally. Not sure it actually needs 'em.. based on my impressions today.
Sound was ..Good.. to Very good.. on venerable 8" full rangers. No clipping , at least to ear hurting levels which were not near max volume knob rotation.
Deep sharp bass, No disapointments there :-)

Problem is: sigh.
I tripped over the left speaker wire, yanking it out of the cheesy Lepai speaker clips. Amp didn't hit the floor or suffer any impacts though. Now the thing will not produce (Any) sound(s) out of the left channel. No clicks, no music
Thinking a mechanical problem induced by the 'yank' I removed and inspected then resoldered back on ALL the plugs on the things rear face.. then reflowed every solder joint on the thing.
Judiciously shorting/touching the underside of the PCB's Ta 2020 chip solder blobs I can produce a hum (equal intensity) for either the left or right speaker.. So ? the sound delivery part of the board seems to be working.
I have a spare Ta 2020 chip but an not keen on replacing it without some degree of certainty that this one is indeed damaged.
Any ideas on this ?
Thanks.

[1MOR]

Re: Modding the Lepai T2020A+

Been following this thread for a while. I ordered up an amp from PE and along the way, ended up with two of these. I had also ordered the small parts per the OP from Mouser, along with the PS upgrade from Ebay. A couple of weeks ago, I lost cable TV and internet access due to hurricane Isaac, so I had some time to get after this project. I found the OEM product to have irratiating HF response, flat midrange and lacking in dynamics. I replaced the PS electrolytic C1 and the output caps, C32,33,35,36,38,39, with the recommended Panny parts. Quite an improvement, even with the supplied PS, and, it still worked! Diving into the project, the remaining through the hole caps were removed and replaced with parts from the Mouser order. As I had forgot about the OP's recommendation to leave C20,21 on the board, they were also removed. Here are a couple of pics showing progress and side by side with the OEM board.



Now, what to do about the unobtanium 1.75uf caps, C20,21. Measuring these original parts, the values varied widely. Knowing that parts will always have some variability, I ordered a selection of caps from Mouser, Panny, Nichicon and Epcos, with values of 1.5uf and 2.2uf. The 1.5uf caps measured all less than 1.5uf and the 2.2uf caps measured greater than 2.2uf with the exception of the Epcos product. Here is a pic showing the variability of the OEM caps labeled 1.75uf and the values of the Epcos caps marked 2.2uf. The Epcos turned out to be a suitable solution.



http://www.mouser.com/Search/Product...41851A9225M000

With the additional parts from Mouser, both boards were completed. The board from amp 2, had the inductors replaced along with the 10R through the hole resistors, R38,39.

http://www.mouser.com/Search/Product...0-MF1/4CC10R0F



The PS electrolytic C1 in amp 2, was leaking its guts onto the board and required some cleaning prior to installing the replacement.
C1 found mounted on the boards of both amps, were marked Nichicon but had poor quality labeling, almost like it had been produced on a cheap printer.

This has proven to be a worthwhile project, the improvement over the OEM Lepai 2020 amp is significant when used with the 5 amp PS. Nicely designed product, nicely done board which resisted my best efforts to damage it, but limited by the OEM supplied parts.

[nottaway]

Re: Modding the Lepai T2020A+

Hi all,

I was curious if this power supply would offer any advantage over the 5A power supply linked in first post?

[1MOR]

Re: Modding the Lepai T2020A+

Hi all,

I was curious if this power supply would offer any advantage over the 5A power supply linked in first post?

If you are referring to my post above, I used this Ebay PS which I believe is the same as the recommendation of the OP.

http://www.ebay.com/itm/280869637201...84.m1438.l2649

[jamikkim]

Re: Modding the Lepai T2020A+

I got my 2020a+ from ebay and it works great except for one issue: sometimes the left channel begins to cut out, but it can be turned "on" again by turning up and down the volume control or by turning off/on the amp.

I'm guessing this is a mechanical issue somewhere, either the relay switch or the inputs/outputs. Any thoughts?...


Also one thing people should check in their new amp is for loose solder flecks that rattle around inside the case - mine had quite a few, wouldn't want these to cause short circuits! Most were somehow on the heatsink not near any components...

[1MOR]

Re: Modding the Lepai T2020A+

I got my 2020a+ from ebay and it works great except for one issue: sometimes the left channel begins to cut out, but it can be turned "on" again by turning up and down the volume control or by turning off/on the amp.

I'm guessing this is a mechanical issue somewhere, either the relay switch or the inputs/outputs. Any thoughts?...


Also one thing people should check in their new amp is for loose solder flecks that rattle around inside the case - mine had quite a few, wouldn't want these to cause short circuits! Most were somehow on the heatsink not near any components...

I did not experience the intermittent problems that you report but, I did notice that the boards were quite dusty, solder remnants were floating about and strings of hot glue extended beyond parts that were glued. I used an old tooth brush, some 99% ISA and some canned air to clean up my boards before and after doing the mods.

You may want to clean up your circuit board and examine the solder joints before proceeding further. You might also consider requesting a replacement from the Ebay seller.

[Soundslike]

Re: Modding the Lepai T2020A+

Couldn't the intermittent output problem be in the volume pot, and might not that be fixed with a shot of cleaner?

[nottaway]

Re: Modding the Lepai T2020A+

If you are referring to my post above, I used this Ebay PS which I believe is the same as the recommendation of the OP.

http://www.ebay.com/itm/280869637201...84.m1438.l2649

No I meant this:

http://www.ebay.com/itm/12-volt-DC-4-a-linear-power-supply-for-CNC-applications-/260401036008?pt=LH_DefaultDomain_0&hash=item3ca11c7ae8

It was hyperlinked just hard to see.....

[jamikkim]

Re: Modding the Lepai T2020A+

The solder joints all seem ok. I think the problem may be the relay switch contacts inside the relay box since tapping it or increasing current (volume) or activating the relay changes the properties of the sound - either both channels will work, sometimes the right channel will be off but usually the left channel has issue.

Unless the seller gives me a free replacement, I probably won't send it back since shipping is $14

[jamikkim]

Re: Modding the Lepai T2020A+

The solder joints all seem ok. I think the problem may be the relay switch contacts inside the relay box since tapping it or increasing current (volume) or activating the relay changes the properties of the sound - either both channels will work, sometimes the right channel will be off but usually the left channel has issue.

Unless the seller gives me a free replacement, I probably won't send it back since shipping is $14

[Mariusmssj]

Re: Modding the Lepai T2020A+

Been following this thread for a while. I ordered up an amp from PE and along the way, ended up with two of these. I had also ordered the small parts per the OP from Mouser, along with the PS upgrade from Ebay. A couple of weeks ago, I lost cable TV and internet access due to hurricane Isaac, so I had some time to get after this project. I found the OEM product to have irratiating HF response, flat midrange and lacking in dynamics. I replaced the PS electrolytic C1 and the output caps, C32,33,35,36,38,39, with the recommended Panny parts. Quite an improvement, even with the supplied PS, and, it still worked! Diving into the project, the remaining through the hole caps were removed and replaced with parts from the Mouser order. As I had forgot about the OP's recommendation to leave C20,21 on the board, they were also removed. Here are a couple of pics showing progress and side by side with the OEM board.

[ATTACH=CONFIG]29302[/ATTACH][ATTACH=CONFIG]29303[/ATTACH]

Now, what to do about the unobtanium 1.75uf caps, C20,21. Measuring these original parts, the values varied widely. Knowing that parts will always have some variability, I ordered a selection of caps from Mouser, Panny, Nichicon and Epcos, with values of 1.5uf and 2.2uf. The 1.5uf caps measured all less than 1.5uf and the 2.2uf caps measured greater than 2.2uf with the exception of the Epcos product. Here is a pic showing the variability of the OEM caps labeled 1.75uf and the values of the Epcos caps marked 2.2uf. The Epcos turned out to be a suitable solution.

[ATTACH=CONFIG]29304[/ATTACH]

http://www.mouser.com/Search/Product...41851A9225M000

With the additional parts from Mouser, both boards were completed. The board from amp 2, had the inductors replaced along with the 10R through the hole resistors, R38,39.

http://www.mouser.com/Search/Product...0-MF1/4CC10R0F

[ATTACH=CONFIG]29305[/ATTACH]

The PS electrolytic C1 in amp 2, was leaking its guts onto the board and required some cleaning prior to installing the replacement.
C1 found mounted on the boards of both amps, were marked Nichicon but had poor quality labeling, almost like it had been produced on a cheap printer.

This has proven to be a worthwhile project, the improvement over the OEM Lepai 2020 amp is significant when used with the 5 amp PS. Nicely designed product, nicely done board which resisted my best efforts to damage it, but limited by the OEM supplied parts.

What kind of inductors did you use? and are they worth changing?