Alright, so I've been using my Lepai amp for well over 2 months now. No problems, runs great. I decided to order two more. I was about to send them to my mom and brother but I figured I'd test them first. I tested the first one, and within 15 seconds there was smoke blowing out every crevice available.
I called up PartsExpress the next day and they sent me a new one free of charge and told me to keep the other one for spare parts or toss it. I figured I'd play with it a bit, so I took it apart.
It appears that what used to be an electrolyte capacitor exploded and left a sticky residue on much of the amp.
So I need some help. I have heard that people have been modding these for a while, but I find very few resources on the actual mods being done. I'd like to replace all of these capacitors with solid state capacitors as a start, and hopefully do something to improve the performance a bit.
Anyone know where I can get the needed parts? Is there a modding thread for these anywhere? I'd like to get some more output and replace parts with better parts to improve sound quality which I have heard has been done with some of these. If there's a thread somewhere that I missed, then that's all I'd really need. I'd also need to know where to get the parts I'll be replacing.
Also, does anyone know where I can get a more powerful power adapter for this? 12V at 2 amps wouldn't give me more than 24W total, yet this thing is supposedly rated for 20W RMS x 2. I imagine a 4 amp power adapter would do?
Thanks in advance!
I called up PartsExpress the next day and they sent me a new one free of charge and told me to keep the other one for spare parts or toss it. I figured I'd play with it a bit, so I took it apart.
It appears that what used to be an electrolyte capacitor exploded and left a sticky residue on much of the amp.
So I need some help. I have heard that people have been modding these for a while, but I find very few resources on the actual mods being done. I'd like to replace all of these capacitors with solid state capacitors as a start, and hopefully do something to improve the performance a bit.
Anyone know where I can get the needed parts? Is there a modding thread for these anywhere? I'd like to get some more output and replace parts with better parts to improve sound quality which I have heard has been done with some of these. If there's a thread somewhere that I missed, then that's all I'd really need. I'd also need to know where to get the parts I'll be replacing.
Also, does anyone know where I can get a more powerful power adapter for this? 12V at 2 amps wouldn't give me more than 24W total, yet this thing is supposedly rated for 20W RMS x 2. I imagine a 4 amp power adapter would do?
Thanks in advance!
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Aren't solid state capacitors limited to 2.3-2.5V types? Either way they're designed for very high frequency circuits and would do rather poorly in audio.
Technically you'd not need a bigger PS as you're not listening to test signals. The typical power consumption when turned up to just before audio clipping is less than 400mA with 4 ohms speakers.
Technically you'd not need a bigger PS as you're not listening to test signals. The typical power consumption when turned up to just before audio clipping is less than 400mA with 4 ohms speakers.
I guess solid state wouldn't be appropriate after all, lol. That's why I asked.
If the power supply is fine, that's great to hear. I was just wondering how something can input 24W and output 40W. Any information on replacement parts to make it sound better, or at minimum, a replacement cap to make this unit work again?
RMS stands for Root of Means squared, ie. it's the average energy level of a sinus wave.
Music signals in order to have any dynamic information have far lower average level. In tests a test signal simulating this is called a gaussian signal. The typically used test signal, and thereby music signal, these days have an average energy level 8 times lower than a sine wave signal.
So with real life use the average power output is actually under 5W total for both channels. There will naturally be peaks but most of this a soaked up by the power supply's overcapacity and the rest by the resevoir cap in the amp.
I would myself prefer a 3A supply but for 90% of all realistic use a 2A is actually fine.
Music signals in order to have any dynamic information have far lower average level. In tests a test signal simulating this is called a gaussian signal. The typically used test signal, and thereby music signal, these days have an average energy level 8 times lower than a sine wave signal.
So with real life use the average power output is actually under 5W total for both channels. There will naturally be peaks but most of this a soaked up by the power supply's overcapacity and the rest by the resevoir cap in the amp.
I would myself prefer a 3A supply but for 90% of all realistic use a 2A is actually fine.
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Well I guess that will have to do. The reason why I asked is that when I play some music at higher volumes with hard bass beats, the light on the volume knob will dim, indicating a loss in voltage.
Based on my knowledge of car audio, this will indicate a voltage drop due to insufficient power. That's why I was wondering if my 2A power adapter is enough or if I should look at something more capable.
With regard to the input cap that blew up, does it need to be a special kind of cap, or can I use any general capacitor? I have 6 330uf caps I was going to use for a subwoofer high pass filter and ended up not needing them for my application, and would love to find a new home for them. Can I just wire up one of those in place of the little cap currently there?
Based on my knowledge of car audio, this will indicate a voltage drop due to insufficient power. That's why I was wondering if my 2A power adapter is enough or if I should look at something more capable.
With regard to the input cap that blew up, does it need to be a special kind of cap, or can I use any general capacitor? I have 6 330uf caps I was going to use for a subwoofer high pass filter and ended up not needing them for my application, and would love to find a new home for them. Can I just wire up one of those in place of the little cap currently there?
I have to admit I was genuinely baffled by the number of people who have "hot rodded" these amps in the big thread in this section. However, not a single person made a writeup on how it should be done, what should be purchased to replace what, and what difference each component makes. I found my replacement for the large input cap that fried, but that's as far as I got, even though I also saw people replacing the 4 inductors parallel to the heatsink and more of the caps all over the boards, among other things I have no knowledge of. If anyone knows of a more concise writeup of what can be done with this amp instead of a dozen or more "hey look what I did with my amp" post assuming everyone knows what they're talking about, I'd very much love to read it.
If not, I'd also very much appreciate it if someone can help me understand what can be improved here so at least I can write something up for other people.
If not, I'd also very much appreciate it if someone can help me understand what can be improved here so at least I can write something up for other people.
Alright, this has me royally confused.
The power adapter that came with the amp is supposedly rated for 2A at 12V. I went digging through a few boxes to find some comparable power supplies and found nothing that did 2A. Actually, the only one that was a comparable size and weight could only output between .6a and .85a.
I took some pictures.
The large power adapter as you can see is rated for 12V 1A, while the Vonage power adapter (which is what comes with the Lepai amps) is rated for 12V 2A. However, the 1A power adapter is twice as heavy, its almost twice as big, yet its rated for half the output?
"does not compute"
The power adapter that came with the amp is supposedly rated for 2A at 12V. I went digging through a few boxes to find some comparable power supplies and found nothing that did 2A. Actually, the only one that was a comparable size and weight could only output between .6a and .85a.
I took some pictures.
The large power adapter as you can see is rated for 12V 1A, while the Vonage power adapter (which is what comes with the Lepai amps) is rated for 12V 2A. However, the 1A power adapter is twice as heavy, its almost twice as big, yet its rated for half the output?
"does not compute"
Hi,
The light small plug pack is an electronic power supply (SMPS), while the larger heavier plug pack uses an iron-core transformer.
The differences are similar to those between an SMPS (Switch Mode Power Supply) and a bulky transformer, rectifier, and large capacitors (and possibly a regulator) that you might use inside a larger amplifier case, except that these power supplies can be larger and of higher capacity than the plug packs.
The light small plug pack is an electronic power supply (SMPS), while the larger heavier plug pack uses an iron-core transformer.
The differences are similar to those between an SMPS (Switch Mode Power Supply) and a bulky transformer, rectifier, and large capacitors (and possibly a regulator) that you might use inside a larger amplifier case, except that these power supplies can be larger and of higher capacity than the plug packs.
That makes sense. thanks for the explanation.
Moving on to parts that could be replaced. Since this is a chinese made $20 amp, I am under the assumption that just about every part inside will have been made with every effort to cut costs and thereby are the lowest quality available. If that is not true, I'd love to know. In any case, here are the parts I've been able to find that can be replaced easily.
The parts list is as follows:
Input capacitor
1 x 16v 3300uf
Other/Output electrolytic capacitors
2 x 16v 100uf
1 x 16v 470uf
2 x 16v 220uf
2 x 50v 1uf
2 x 50v 1.7uf
Other/Output film capacitors
1x 63v .1uf - 104j
6x ?v .47uf - 474z
Inductors:
5 x 10uH - 100k
I didn't calculate the value of the tiny worm-like band color things, presumably resistors. Didn't seem like anything significant enough to bother with, but I'd like to know if I should be replacing those as well.
Being essentially a Class D amp, I have heard that the inductor quality is important. Can anyone comment on this? Any suggestions as to what kinds of capacitors I can use to replace the current ones?
Alright, I found superior audio grade replacements for all of the caps on the board with the exception of the ones above the heatsink labeled "474 Z"
These don't have a voltage rating written on them, so I have absolutely no idea what to buy. There are 100V versions available in the 5% tolerance variety, but they're $3.19 apiece, which is quite expensive compared to the others and will end up costing me almost as much as the entire amp since I need 6 of them. These do appear to be output caps based on their proximity to the terminals, but I'm not an expert so what do you guys think?
The "Z" rating on these represents a tolerance rating of -20%/+80%. Anyone have any idea what this means?
These don't have a voltage rating written on them, so I have absolutely no idea what to buy. There are 100V versions available in the 5% tolerance variety, but they're $3.19 apiece, which is quite expensive compared to the others and will end up costing me almost as much as the entire amp since I need 6 of them. These do appear to be output caps based on their proximity to the terminals, but I'm not an expert so what do you guys think?
The "Z" rating on these represents a tolerance rating of -20%/+80%. Anyone have any idea what this means?
Here are the replacement parts I ordered:
3x Polypropylene Film Capacitors 0.10uF 450VDC 5% (to replace the red one to the right of the Tripath chip)
https://www.mouser.com/Search/Produ...HDvirtualkey64700000virtualkey647-UKW1C472MHD
18x Polypropylene Film Capacitors 0.47uF 450VDC 5% (to replace the blue 474 low tolerance ones)
https://www.mouser.com/Search/Produ...DDvirtualkey64700000virtualkey647-UKW1C101MDD
1x Aluminum Electrolytic Capacitors - Leaded 16VDC 5600uF (for fiddling around with as a larger input cap than the 4700uf)
https://www.mouser.com/Search/Produ...PDvirtualkey64700000virtualkey647-UKW1C471MPD
6x Aluminum Electrolytic Capacitors - Leaded 50volts 2.2uF 20% (direct replacement)
https://www.mouser.com/Search/Produ...PDvirtualkey64700000virtualkey647-UKW1E221MPD
6x Aluminum Electrolytic Capacitors - Leaded 50volts 1uF 20% (direct replacement)
https://www.mouser.com/Search/Produ...DDvirtualkey64700000virtualkey647-UKW1H010MDD
6x Aluminum Electrolytic Capacitors - Leaded 25volts 220uF 20% (direct replacement)
https://www.mouser.com/Search/Produ...DDvirtualkey64700000virtualkey647-UKW1H2R2MDD
3x Aluminum Electrolytic Capacitors - Leaded 16volts 470uF 20% (direct replacement)
https://www.mouser.com/Search/Produ...62virtualkey66720000virtualkey667-EEU-FR1C562
6x Aluminum Electrolytic Capacitors - Leaded 16volts 100uF 20% (direct replacement)
https://www.mouser.com/Search/Produ...virtualkey99990000virtualkey667-ECW-F2W474JAQ
3x Aluminum Electrolytic Capacitors - Leaded 16volts 4700uF 20% (input cap replacement)
https://www.mouser.com/Search/Produ...virtualkey99990000virtualkey667-ECW-F2W104JAQ
These should ship out tomorrow via UPS so I'll be able to get started next week. Since I happen to have two identical amps that have not been used, I'll be able to report back the results after I mod one of them.
I've decided against replacing the inductors btw. The polypropylene capacitors I've read are great around heat compared to ceramics and a few other kinds, which is good considering they're right next to the heatsink, and the electrolytic capacitors are apparently "audio grade," whatever that means.
3x Polypropylene Film Capacitors 0.10uF 450VDC 5% (to replace the red one to the right of the Tripath chip)
https://www.mouser.com/Search/Produ...HDvirtualkey64700000virtualkey647-UKW1C472MHD
18x Polypropylene Film Capacitors 0.47uF 450VDC 5% (to replace the blue 474 low tolerance ones)
https://www.mouser.com/Search/Produ...DDvirtualkey64700000virtualkey647-UKW1C101MDD
1x Aluminum Electrolytic Capacitors - Leaded 16VDC 5600uF (for fiddling around with as a larger input cap than the 4700uf)
https://www.mouser.com/Search/Produ...PDvirtualkey64700000virtualkey647-UKW1C471MPD
6x Aluminum Electrolytic Capacitors - Leaded 50volts 2.2uF 20% (direct replacement)
https://www.mouser.com/Search/Produ...PDvirtualkey64700000virtualkey647-UKW1E221MPD
6x Aluminum Electrolytic Capacitors - Leaded 50volts 1uF 20% (direct replacement)
https://www.mouser.com/Search/Produ...DDvirtualkey64700000virtualkey647-UKW1H010MDD
6x Aluminum Electrolytic Capacitors - Leaded 25volts 220uF 20% (direct replacement)
https://www.mouser.com/Search/Produ...DDvirtualkey64700000virtualkey647-UKW1H2R2MDD
3x Aluminum Electrolytic Capacitors - Leaded 16volts 470uF 20% (direct replacement)
https://www.mouser.com/Search/Produ...62virtualkey66720000virtualkey667-EEU-FR1C562
6x Aluminum Electrolytic Capacitors - Leaded 16volts 100uF 20% (direct replacement)
https://www.mouser.com/Search/Produ...virtualkey99990000virtualkey667-ECW-F2W474JAQ
3x Aluminum Electrolytic Capacitors - Leaded 16volts 4700uF 20% (input cap replacement)
https://www.mouser.com/Search/Produ...virtualkey99990000virtualkey667-ECW-F2W104JAQ
These should ship out tomorrow via UPS so I'll be able to get started next week. Since I happen to have two identical amps that have not been used, I'll be able to report back the results after I mod one of them.
I've decided against replacing the inductors btw. The polypropylene capacitors I've read are great around heat compared to ceramics and a few other kinds, which is good considering they're right next to the heatsink, and the electrolytic capacitors are apparently "audio grade," whatever that means.
I posted the wrong order of links for the above descriptions. Edited version:
3x Polypropylene Film Capacitors 0.10uF 450VDC 5% (to replace the red one to the right of the Tripath chip)
https://www.mouser.com/Search/Produ...virtualkey66720000virtualkey667-ECW-F2W104JAQ
18x Polypropylene Film Capacitors 0.47uF 450VDC 5% (to replace the blue 474 low tolerance ones)
https://www.mouser.com/Search/Produ...virtualkey66720000virtualkey667-ECW-F2W474JAQ
1x Aluminum Electrolytic Capacitors - Leaded 16VDC 5600uF (for fiddling around with as a larger input cap than the 4700uf)
https://www.mouser.com/Search/Produ...62virtualkey66720000virtualkey667-EEU-FR1C562
6x Aluminum Electrolytic Capacitors - Leaded 50volts 2.2uF 20% (direct replacement)
https://www.mouser.com/Search/Produ...DDvirtualkey64700000virtualkey647-UKW1H2R2MDD
6x Aluminum Electrolytic Capacitors - Leaded 50volts 1uF 20% (direct replacement)
https://www.mouser.com/Search/Produ...DDvirtualkey64700000virtualkey647-UKW1H010MDD
6x Aluminum Electrolytic Capacitors - Leaded 25volts 220uF 20% (direct replacement)
https://www.mouser.com/Search/Produ...PDvirtualkey64700000virtualkey647-UKW1E221MPD
3x Aluminum Electrolytic Capacitors - Leaded 16volts 470uF 20% (direct replacement)
https://www.mouser.com/Search/Produ...PDvirtualkey64700000virtualkey647-UKW1C471MPD
6x Aluminum Electrolytic Capacitors - Leaded 16volts 100uF 20% (direct replacement)
https://www.mouser.com/Search/Produ...DDvirtualkey64700000virtualkey647-UKW1C101MDD
3x Aluminum Electrolytic Capacitors - Leaded 16volts 4700uF 20% (input cap replacement)
https://www.mouser.com/Search/Produ...HDvirtualkey64700000virtualkey647-UKW1C472MHD
3x Polypropylene Film Capacitors 0.10uF 450VDC 5% (to replace the red one to the right of the Tripath chip)
https://www.mouser.com/Search/Produ...virtualkey66720000virtualkey667-ECW-F2W104JAQ
18x Polypropylene Film Capacitors 0.47uF 450VDC 5% (to replace the blue 474 low tolerance ones)
https://www.mouser.com/Search/Produ...virtualkey66720000virtualkey667-ECW-F2W474JAQ
1x Aluminum Electrolytic Capacitors - Leaded 16VDC 5600uF (for fiddling around with as a larger input cap than the 4700uf)
https://www.mouser.com/Search/Produ...62virtualkey66720000virtualkey667-EEU-FR1C562
6x Aluminum Electrolytic Capacitors - Leaded 50volts 2.2uF 20% (direct replacement)
https://www.mouser.com/Search/Produ...DDvirtualkey64700000virtualkey647-UKW1H2R2MDD
6x Aluminum Electrolytic Capacitors - Leaded 50volts 1uF 20% (direct replacement)
https://www.mouser.com/Search/Produ...DDvirtualkey64700000virtualkey647-UKW1H010MDD
6x Aluminum Electrolytic Capacitors - Leaded 25volts 220uF 20% (direct replacement)
https://www.mouser.com/Search/Produ...PDvirtualkey64700000virtualkey647-UKW1E221MPD
3x Aluminum Electrolytic Capacitors - Leaded 16volts 470uF 20% (direct replacement)
https://www.mouser.com/Search/Produ...PDvirtualkey64700000virtualkey647-UKW1C471MPD
6x Aluminum Electrolytic Capacitors - Leaded 16volts 100uF 20% (direct replacement)
https://www.mouser.com/Search/Produ...DDvirtualkey64700000virtualkey647-UKW1C101MDD
3x Aluminum Electrolytic Capacitors - Leaded 16volts 4700uF 20% (input cap replacement)
https://www.mouser.com/Search/Produ...HDvirtualkey64700000virtualkey647-UKW1C472MHD
Alright, status update.
Got the crossover parts in. The 4700uf "audio grade" caps and the 5600uf "low ESR" cap are the exact same size, and they both fit in the location of the old one as a direct replacement. There's definitely enough vertical clearance.
The replacement power adapter also arrived, and I got to test that just now. Previously, the amp's lights would start dimming and the amp would shut down at just over the 1/2 volume point when testing an Aura NS6 off of one channel. Now, I can crank it past the 3/4 point and the lights don't even dim, let alone have the amp shut down.
I have concluded that the 2A power adapter these things come with is insufficient by a long shot. It should be thrown away immediately and replaced with a larger unit that can actually provide the rated power. The one I got provides up to 6A at 12V.
I didn't get a chance to replace any of the caps, but I figured I'd share my findings so far.
Got the crossover parts in. The 4700uf "audio grade" caps and the 5600uf "low ESR" cap are the exact same size, and they both fit in the location of the old one as a direct replacement. There's definitely enough vertical clearance.
The replacement power adapter also arrived, and I got to test that just now. Previously, the amp's lights would start dimming and the amp would shut down at just over the 1/2 volume point when testing an Aura NS6 off of one channel. Now, I can crank it past the 3/4 point and the lights don't even dim, let alone have the amp shut down.
I have concluded that the 2A power adapter these things come with is insufficient by a long shot. It should be thrown away immediately and replaced with a larger unit that can actually provide the rated power. The one I got provides up to 6A at 12V.
I didn't get a chance to replace any of the caps, but I figured I'd share my findings so far.
I think I'll probably just stop posting updates here. Its becoming hard to believe that anyone at all even reads these posts. If anyone comes across this in the future, there are more updates here:
Lepai T2020A+ Repair/Upgrade - Techtalk Speaker Building, Audio, Video, and Electronics Customer Discussion Forum From Parts-Express.com
Lepai T2020A+ Repair/Upgrade - Techtalk Speaker Building, Audio, Video, and Electronics Customer Discussion Forum From Parts-Express.com
I have a writeup on modifying/upgrading this amp here:
Modding the Lepai T2020A+ - Techtalk Speaker Building, Audio, Video, and Electronics Customer Discussion Forum From Parts-Express.com
Modding the Lepai T2020A+ - Techtalk Speaker Building, Audio, Video, and Electronics Customer Discussion Forum From Parts-Express.com
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