No. They only mention 4ohm and 8ohm configuration. Probably best to stick with the default values on your board in that case. I'm not qualified to make a judgement of what values to use or why to use such values.
Perhaps someone else around here is.
Perhaps someone else around here is.
They are part of the low pass filter that turns the Class D output square wave into an audio signal. You could use better caps (film, as these are most likely ceramic), but stick with the values shown unless you know how to calculate the right values for your speakers.
It's a pretty good unit. Common parts and the schematic is available online. Mine is all-original and still going strong at 35 years old. There's one on ebay now for a $25 bid including shipping.
I never met a power transformer I didn't like. I'll salvage 'em all, and have a few 5 gallon buckets full of different types.
I never met a power transformer I didn't like. I'll salvage 'em all, and have a few 5 gallon buckets full of different types.
Great Thread.🙂 I will be ordering one of these from PE soon and was wondering what are the most significant mods are so I can order what else I need from them at the same time, provided PE has what I will need.
Just a small note to those who plan to heavily modify the Lepai:
If you plan to remove and/or bypass the volume and tone controls, and then spend some money on upgrading some other components, I suggest an alternative; buy this instead http://www.ebay.ca/itm/370738187019
It already has better components installed and it sounds fantastic compared to a stock Lepai, and it is basically the same price. Hook up your pre-amp of choice and Bob's your uncle. Sure you can still upgrade the main power cap to a bigger one and maybe stick in some POI input caps (I did both) but overall this is a better way to spend the 20 bucks and change, if you don't need the volume/tone and ugly chassis.
If you plan to remove and/or bypass the volume and tone controls, and then spend some money on upgrading some other components, I suggest an alternative; buy this instead http://www.ebay.ca/itm/370738187019
It already has better components installed and it sounds fantastic compared to a stock Lepai, and it is basically the same price. Hook up your pre-amp of choice and Bob's your uncle. Sure you can still upgrade the main power cap to a bigger one and maybe stick in some POI input caps (I did both) but overall this is a better way to spend the 20 bucks and change, if you don't need the volume/tone and ugly chassis.
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The lepai amplifiers are so bad they are not even worth modifying, a much better value for money is the SMSL SA-S1 amp.
While I appreciate the answers, I like to mod stuff and I also like to keep, what I can, of the U.S dollars I have in the U.S.
This little thing is going to be used only for background music from a laptop in my machine/fab shop. From what I am seeing at PE and what's available from them, it looks like I would have to get any mod parts from Mouser anyway.
This little thing is going to be used only for background music from a laptop in my machine/fab shop. From what I am seeing at PE and what's available from them, it looks like I would have to get any mod parts from Mouser anyway.
Output caps
The TA2020 datasheet application test circuit shows 4 or 8 ohm load can be used, however there is an asterisk beside the 8ohm. In the notes section under the circuit, it states:
* Use Co = 0.22μF and Cz=0.22uF for 8 Ohm loads
That being the case I would try .33uF for 6 ohm.
Make one mod to one channel then compare left to right.
The TA2020 datasheet application test circuit shows 4 or 8 ohm load can be used, however there is an asterisk beside the 8ohm. In the notes section under the circuit, it states:
* Use Co = 0.22μF and Cz=0.22uF for 8 Ohm loads
That being the case I would try .33uF for 6 ohm.
Make one mod to one channel then compare left to right.
Well.. at least 'some' of the $ will go to 'muricans.
PE is only a reseller. Still a 'Made en Chine' lashup using fake components.
Although PE does give excellent service. Unlike Chinese Fleabay merchants.
IF after a cheapy? Hunt up a YJ ta 2020 amp on Fleabay.
Less Coin, also much reduced need to mod it as it's a much closer to the Tripath designed/suggested circuit.. than ANY lepai.. Box stock
What I would LIKE to find is a bare PCB and populate it myself. My searches have come up with nothing.
Thanks for the links but, given that the shipping from BFE is more than double than what the PCB costs, I would be better off etching my own for that price.
Ummmmm........Perhaps there is something there.
Ummmmm........Perhaps there is something there.
Not quite the same
Bare, I tried this and it takes a few more turns with thicker wire. The original wire on mine was appox 0.38mm thick and all measured right at 9.5 uH. I replaced with 0.65mm wire from a transformer. I played with it till I found a 12.5" length would give the desired 10uH. I think it was 22 turns? Best to use a meter.
I left two of the coils untouched on one side and modified two on the other. I wanted a side by side comparison. It may be a little while till I get to test as I've removed everything I want to change and I'm modding a nice little cigar box for it to go into.
Bare, I tried this and it takes a few more turns with thicker wire. The original wire on mine was appox 0.38mm thick and all measured right at 9.5 uH. I replaced with 0.65mm wire from a transformer. I played with it till I found a 12.5" length would give the desired 10uH. I think it was 22 turns? Best to use a meter.
I left two of the coils untouched on one side and modified two on the other. I wanted a side by side comparison. It may be a little while till I get to test as I've removed everything I want to change and I'm modding a nice little cigar box for it to go into.
That IS strange. Done more than a few over the years.
In truth tho.. usually a bit bigger / more involved than the Wee Lepai ones.
Although Given that it's a simple Hash filter circuit on these.
This really Will Not have audible effect .
Only the Series resistance bottleneck was the issue.
Sadly I've pretty well come to the end of my Patience with these Lepai boxes.
Another one ...just died... today!
First one I fried by tripping over the speaker wires .. Doh!
Second Lepai lost one channel all by itself... while operating.
Today the Third! one also shed a channel. Exactly as the 2nd one.
For No explicable reason.
Everything checks out.. except the Chip.
My Guess is that the Fake Ta 2020 chips fail after prolonged use.
(6 months??)
Possibly dependent on just how shitty that particular Fake production run was.
I have 3 remaining GENUINE Ta 2020 Chips..I won't be wasting/inserting any into these goof ball Lepai PCBs though.
One day (?) I'll build up a Tripath Circuit..
In truth tho.. usually a bit bigger / more involved than the Wee Lepai ones.
Although Given that it's a simple Hash filter circuit on these.
This really Will Not have audible effect .
Only the Series resistance bottleneck was the issue.
Sadly I've pretty well come to the end of my Patience with these Lepai boxes.
Another one ...just died... today!
First one I fried by tripping over the speaker wires .. Doh!
Second Lepai lost one channel all by itself... while operating.
Today the Third! one also shed a channel. Exactly as the 2nd one.
For No explicable reason.
Everything checks out.. except the Chip.
My Guess is that the Fake Ta 2020 chips fail after prolonged use.
(6 months??)
Possibly dependent on just how shitty that particular Fake production run was.
I have 3 remaining GENUINE Ta 2020 Chips..I won't be wasting/inserting any into these goof ball Lepai PCBs though.
One day (?) I'll build up a Tripath Circuit..
I've had my Lepai for 2 years or so and haven't had any problem. Sometimes playing and/or idling for days on end. It's in a smallish room, though, and has rarely been asked to put out more than about 5wpc@4Ω, since its first day out of the box.
Well, I ordered one from PE. As well as a few other things to go with it. 4700uf cap for the power side and a pair of 2.2uf Audyn foil caps for the input side. I plan on bypassing the tone controls and wiping the board of both opamps. There should be enough room for both 2.2uf caps where the opamps use to be.
Originally, I was going to place it in a new case but decided that this little amp isn't worth all that. So, I am just going to bead blast the main case and re-paint and replace the end pieces with something else, just haven't decided on what yet. I am also loosing the spring speaker terminals for binding posts.
I should have the goods in by the end of the week and will follow up with a Mouser order to replace the inductors and caps on the output side.
Should be posting pics after the weekend.
Originally, I was going to place it in a new case but decided that this little amp isn't worth all that. So, I am just going to bead blast the main case and re-paint and replace the end pieces with something else, just haven't decided on what yet. I am also loosing the spring speaker terminals for binding posts.
I should have the goods in by the end of the week and will follow up with a Mouser order to replace the inductors and caps on the output side.
Should be posting pics after the weekend.
Well, I got the goods in today. But I won't be modding this one. Arrived DOA from PE. Really a let down. Been waiting and researching these things for a couple weeks only for it to get here and not work from the start. It lights up but no sound. Time to contact PE for a replacement.
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