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Old 22nd April 2012, 06:52 PM   #1141
Franfj is offline Franfj  Spain
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Quote:
Originally Posted by ads2 View Post
I have to buy one but motorized so I may use the same.
Or better I may try to use some cheap pots with different values to see what value will fit best.
Do someone know waht will I have to do to add a balance pot ?
My Thorens amplifier panel has a hole for Balance, and would like to keep the same design.
Potentiometers (Beginners' Guide to Pots) Have a look at picture 7
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Old 22nd April 2012, 07:03 PM   #1142
ads2 is offline ads2  France
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Gracias Franfj
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Old 1st May 2012, 04:54 PM   #1143
swon is offline swon  United States
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Originally Posted by Franfj View Post
I don't think that anybody that buys a 20$ Amp spends 54$ in a volume control…

Anyway, I will try to answer your questions about getting the Amp in a wooden enclosure.

First this is my Amp after a lot of modding… the left switch is for power, the right for tone bypass, the green led for power, the red for overload:

In my Amp, the idea was to fit inside both power supply and amp, but I have to leave that idea because the power supply make a lot of electrostatic noise u_u so that leaved most of the case empty and that big hole at back (which was for a standard power cable).

First problem making a wood enclosure is wall thickness, you will have problems with most of the Lepai components, if you change potentiometers, switches, etc. make sure you get ones with long shaft to avoid problems.

The second problem comes here, replacing parts requires some investigation about how works, and how you can replace them. For example, you won't be able to use the switch that you have bought for tone bypassing, and a lot of more work for other parts…

Then the next big problem is wiring the whole thing, each potentiometer has 6 legs, so 6 * 3 = 18 solder points, if you put them away like I have done you will have to wire them so 18 * 2 = 36 solder points only for potentiometers!!

If I were you, first will try to open the amp, and guess to know how works…
That is awesome, thanks for sharing! Yeah, mounting the potentiometers is one of the questions I have. For my first Lepai-modding project I am keeping it simple with a jigsaw hole in the speaker (DIY active speakers) and mounting the faceplate on the outside of the front of the speakerbox. Then a terminal cup with speaker wire extensions internally to hook up the second speaker externally, with panel-mount jacks for the power cable (2.1 to 2.5mm for the larger 12V 5A power supply) and minijack (for external input via minijack or RCA Stereo with an adapter). That requires minimal modding, but gives me a good first experiment. I would definitely like to use custom pots & knobs for the second project.
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Old 5th May 2012, 07:39 PM   #1144
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Just received one of these. Using it with old Kef Coda III speakers that I was using with a Nad 3020 before it stopped working. I didn't get a power supply with it so I am using a 12v 4A ps from an old tft monitor.

So far I can't make my mind up over the sound. Sometimes it doesn't sound too bad but other times it sounds quite poor. Quite a harsh sound but can be 'muddy'. Some tracks sound good however.

I thought I would put a pic of the board up as it differs a bit from the one on the wiki. I know very little about electronics but there are some differences I have noticed. The inductor after the power input has been changed as have all the output inductors. The opamps look to be the same but there are now 2 resistors soldered across the legs of each one?

Perhaps someone with more knowledge will spot more changes.
Attached Images
File Type: jpg board.jpg (100.5 KB, 365 views)
File Type: jpeg inductor.jpeg (70.9 KB, 347 views)
File Type: jpeg opamp.jpeg (94.6 KB, 345 views)
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Old 5th May 2012, 08:26 PM   #1145
JoeDJ is offline JoeDJ  United States
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.............So far I can't make my mind up over the sound. Sometimes it doesn't sound too bad but other times it sounds quite poor. Quite a harsh sound but can be 'muddy'. Some tracks sound good however................
I have come to the same conclusion with that Lapai amp....... even with a "Topping T20mk2" (T2020) which is much more refined (both in constuction and sound) than the Lepai.

They do lack crossover distortion but, their limited power raises the harmonic distortion levels frequently , even at low volumes with, loud transients.
Also , the rising hi end may sound good with some program sources but, it can be anoying with others.
So, I have given up on them for the most part.

I suppose they do serve a real purpose where space is limited and only very low volumes are needed.

Last edited by JoeDJ; 5th May 2012 at 08:49 PM.
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Old 7th May 2012, 12:41 AM   #1146
blossom is offline blossom  New Zealand
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Took a while but finally read this entire thread! A bit much really, took me a few days! Now ill get my own wee lepai project under way, will report back in a while. Thanks to all those that have contributed so far, its pretty much all been covered! To those that are jumping on board, do use the search function as I stated it has all pretty much been covered. One thing I didn't see though, reworking the opamp stage of the LP-2020A+ board. Is it possible for the average guy with it all being SM or?(one guy replaced opamps but with issues, sorry i cant find a reffereance to that) As I doubt it would be right....
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Old 7th May 2012, 01:08 AM   #1147
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It would surprise me if I was the only guy that replaced the op amps on his Lepai. The only serious issue I had was some stability problems (I don't even recall how exactly they manifested themselves) but they fixed themselves. And I find it did remove much of the harshness I could get out of the stock amp (it could become genuinely painful to listen to). I had some SMT LM833's handy and used those. Many satisfied listening hours later, I wouldn't hesitate to do it again.
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Old 7th May 2012, 01:21 AM   #1148
blossom is offline blossom  New Zealand
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I must search and find the post from somebody that did it earlier, they reported some"hissing or so" untill its volume got past about 1 O'clock. Pretty sure he used same op's as you.
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Old 7th May 2012, 02:04 AM   #1149
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Yes, that rings a bell. My post so it wasn't too difficult to find. Post #857 was a recap (the summary kind ).
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Old 7th May 2012, 09:43 AM   #1150
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Originally Posted by JoeDJ View Post
I have come to the same conclusion with that Lapai amp....... even with a "Topping T20mk2" (T2020) which is much more refined (both in constuction and sound) than the Lepai.

They do lack crossover distortion but, their limited power raises the harmonic distortion levels frequently , even at low volumes with, loud transients.
Also , the rising hi end may sound good with some program sources but, it can be anoying with others.
I was expecting the bass to be a bit lacking after reading the thread and tbh it is better than I thought it would be but could be better. The highs can be too loud and harsh. The worst thing however is the mids seem to have no separation if there is a lot going on.
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