LP-2020A+ mod thread

[sofaspud]

Am I on the right tracks? Has anyone solved this problem? Thanks in advance!

Yes, the track is right. An LDO regulator will work. I didn't look closely but it appears that linked TI chip is suitable. But note that the Vdrop is (max) 1.5V @ 3A. So...
It would probably be easier to just put a 3A Schottky diode (eg, 1N5822) in series with the positive lead from the battery. It will drop a half-volt or less, and put the supply into the Lepai's operating range even at full charge.

 

[npnr]

Cool thanks sofaspud. I hadn't heard of a Schottky diode. I'll give that a go as it sounds just the ticket. It's super cheap too compared with some of the solutions I was looking at!

 

[ForenSeil]

Hi, I sometimes run my lepai from a 12v lead acid battery. Unfortunately when it's fully charged the voltage is sometimes too high and the amp won't work. I'm thinking that I need a low dropout voltage regulator, but I'm not an electronics engineer...

RS Components

Am I on the right tracks? Has anyone solved this problem? Thanks in advance!

BTW
The Lepai is capped to work with 14.5V max., as the TK2050 chipset breaks quite fast when used with higher voltages.

If your battery is charged higher than 14.5V your battery charger might be crappy (unregulated), as for most LA batteries >14.5V is too much.
Did your charger came with your battery? If not and it's a simple charger I would recommend to measure idle voltage of your charger.
Only a very few LA batteries can handle charges up to ~14.7V but most are running better (and all living very much longer) when only charged up to 14.1-14.4V which is only <10% capacity difference to 14.7V

If you have to/want to buy a new charger I do recommend Imax B6 or Imax B6AC - they can be had for <25$ on Ebay, DX.com etc., they have a display that shows battery capacity and current current etc., you can adjust charging rate to your battery size (you should not charge LA batteries with more than 1/10 of their capacity, for example you should load a 50Ah batterie not with more than 5A) and they do also charge LiPo, NiCD and other batteries (including functions for balancing cells)

 

[lutkeveld]

@FOrenseil Ah that explains your recommendation in the other thread. The Lepai doesn't have a TK2050 chip onboard, it's the TA2020.

 

[WaFfLe]

So, I just completed the mods tonight and it made a major difference. I followed a couple different builds and changed a few parts. I'll post the results and Part list soon.

 

[WaFfLe]

so i bought the 2020a+ and it sounded ok, Lots of background noise and anything above half volume started distorting.
researched mods that had been completed by a few people, created a parts list and off i went.

 

[WaFfLe]

tore it down to get a game plan together

 

[WaFfLe]

thanks to mouser, i was able to get everything i needed....
(parts list if you want to do the same build)
op amps NE5532D
c1 EEU-FR1C562
c3 UKW1C471MPD
c4 c10 UKW1H010MDD
c9 ECW-F2W104JAQ
c14 c15 UFW1A221MED
c20 c21 UKW1H2R2MDD
c28 c29 UKW1C101MDD
c30 c31 MKS2C043301K00JSSD
c32 c33 c35 c36 c38 c39 ECW-F2W474JAQ
L1 6100-100K-RC
L2 L3 L4 L5 744732100
Power Supply GSM60A12-P1J (Mean Well 12v 5a)

 

[WaFfLe]

assembly really wasnt hard at all!
even the surface mounted op amps didnt give me trouble despite all the info on the interwebs scaring me about having to use solder paste and junk...
i used a super fine tipped solder iron and alittle flux, those things dropped right in

 

[WaFfLe]

now onto the custom wiring... i removed everything but the pots and that little tone control switch thingy

 

[WaFfLe]

also, i HATED the original car amplifier looking case, looked like cheap crap.....
Hello cigar box!
i added banana jacks, gold plated inputs, panel mount power, aluminum power switch, motherboard standoffs

 

[WaFfLe]

mounted the completed board and connected the inputs/outputs with solid copper wire that i shrink tubed.
the input cable came from an old set of RCA wires so i could keep a "shielded" signal

 

[WaFfLe]

adding a few vintage 70's control knobs to further my build from the cheapness that is the stock amp look.
its done for now but i am still working on the lid and box finish (i might poly the box)

 

[WaFfLe]

one thing i forgot to mention, i had separated the tripath chip from the heat sink and thoroughly cleaned then applied Artic Silver 5 (even though this probably didnt make ANY difference) the chip runs pretty cool even before modifying the entire board.
one thing i would like to mention is that after switching the components (and this may have to do directly with the op amps) the bottom end is now super strong and the overall clarity is a complete 180 from stock sound

 

[WaFfLe]

The cigar box is a Onyx No. 4. Picked it up for $7 and it has more than enough room to add alittle "luxury" to the lepai

 

[WaFfLe]

Well... It's all together and running! Only thing I might add is some brass feet to match the hinges.

 

[Fynn]

I'm still amazed, that my modified amp is still working without problems for 2.5 Years now, 12+hours daily usage. (Same goes to the 10$ Chinese psu).


From when i first started reading about it, then buying and modding it, i would have never thought it is going to make it so far.

 

[WaFfLe]

I picked it up after seeing all the neat mods and stuff peopl have done with it. Also it was a learning experience that I could use on other projects.
It seems the lepi or "lepy" company that makes these has been reading the forums and mods because they actually applied some of the mods to the design and put them into the next model!
Take a look at this new version with upgraded components...

 

[Renron]

Waffle,
those mods are a work of love, very nicely done. Beautiful, looks like you enjoyed the re build.
That photo is of a 2024A+, I wonder if the 2020A+ has the same upgrades? I should get mine today, anxiously awaiting with screwdriver......
No heatsink? or is it under the chip?

 

[WaFfLe]

The 2024 has a different tripath chip that is physically smaller. Apparently it doesn't produce as much heat as the 2020 so it doesn't have any mechanical heat dissipation.
It was definitely a fun build, I don't know why people complained about changing the opamps because it wasn't hard at all. I use a pencil tip solder iron and tinned the pads for the replacement op. To remove it, I have a soldering heat gun specifically for smd parts.
I do have an unfortunate update though, I had this thing running for a very long time at high volumes and now the amp goes into protection mode flipping the relays anytime over 1/4 volume.