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Old 21st July 2013, 05:36 PM   #1611
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Quote:
Originally Posted by KopiOkaya View Post
I don't want to sound like your faithful sidekick or yesman, but I have to say "yes". I have been into hifi for over 20 years and ever since I discovered T-amps, my entire concept and impression about high-end audio has changed. I am still keeping my "big gears" though but only to be used as showpieces to my house guests. Nowadays, the background music comes mainly from the Lepai.

I, too, have aged and my hearing isn't as good as before. I seldom attend live concert but I know my ears aren't as "tolerant" as they used to be. Loud music, low sub-bass and high shrill irritates me. So, I must say T-amps are godsend for seniors like myself. By the way, my 78 year-old dad loves his Lepai too.
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Old 21st July 2013, 05:45 PM   #1612
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[off-topic]

Oooo.

I just starting looking into Nuforce kit. Hmmm!

Nothing like the ridiculous value that Tripath-based stuff offers, but not 'audiophile' pricing either - VERY intriguing.

Not least is that their amps have a proper, low-impedence output.

[/off-topic]
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Old 21st July 2013, 06:02 PM   #1613
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Originally Posted by jerrymchill View Post
Gents - you might like this read:
lepai tripath amplifier
OK, I'm confused about the NSMT mod writeup. There's a link to a "kit" but NSMT's website only seems to sell modded amps. The prices for the modded Lepais are certainly reasonable - perhaps too reasonable. That little cabinet alone must surely represent a minimum of half the difference between the cost of a stock Lepai and the modded version.

Does anyone know what these mods actually consist of?

The Lepai is my absolute least favorite Tripath / small class D amp of the many I've tried, like, WAY down there at the bottom, to the point where I won't even loan one to someone hearing a T-amp for the first time. A lot of the problems seem to lie in the "preamp," which I would think would require fairly significant modification to rectify the MANY problems it causes. (I have three of the Lepais, all purchased ca. 2011; they all suffer from the same problems that none of my other 2024/2020-based amps have - specifically, TOTALLY excessive background noise and far-too-early distortion, especially with the tone circuit engaged. Not crazy about the centering of the tone controls either.)
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Old 21st July 2013, 06:17 PM   #1614
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Originally Posted by lossfound View Post
Does anyone know what these mods actually consist of?
I was disappointed that more information on the mods wasn't provided, but decided they are most likely covered here anyway.
Quote:
A lot of the problems seem to lie in the "preamp," which I would think would require fairly significant modification to rectify the MANY problems it causes.
A large number of diy'ers here have just bypassed the entire preamp/tone circuitry.
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Old 21st July 2013, 06:27 PM   #1615
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Originally Posted by lossfound View Post
OK, I'm confused about the NSMT mod writeup. There's a link to a "kit" but NSMT's website only seems to sell modded amps. The prices for the modded Lepais are certainly reasonable - perhaps too reasonable. That little cabinet alone must surely represent a minimum of half the difference between the cost of a stock Lepai and the modded version.

Does anyone know what these mods actually consist of?

The Lepai is my absolute least favorite Tripath / small class D amp of the many I've tried, like, WAY down there at the bottom, to the point where I won't even loan one to someone hearing a T-amp for the first time. A lot of the problems seem to lie in the "preamp," which I would think would require fairly significant modification to rectify the MANY problems it causes. (I have three of the Lepais, all purchased ca. 2011; they all suffer from the same problems that none of my other 2024/2020-based amps have - specifically, TOTALLY excessive background noise and far-too-early distortion, especially with the tone circuit engaged. Not crazy about the centering of the tone controls either.)
I have to confess I haven't read right though this thread, or really got my head around the 'topology' of the Lepai.

I have heard that who-ever designed it dis-regarded much of the 'reference' layout for Tripaths.

What actually constitutes the input ('preamp') the source 'sees'? Is it an opamp?

I hasten to add that I'm a complete dilettante when it comes to electronics, but I understand the principles.

Last edited by Aleksunder; 21st July 2013 at 06:30 PM.
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Old 21st July 2013, 06:33 PM   #1616
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Originally Posted by Aleksunder View Post
What actually constitutes the input ('preamp') the source 'sees'? Is it an opamp?
Just going from memory, so I could well be wrong, but I think it is a 10k ohm (?) series resistor and the 20k ohm (?) volume potentiometer.
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Old 21st July 2013, 07:30 PM   #1617
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Originally Posted by sofaspud View Post
Just going from memory, so I could well be wrong, but I think it is a 10k ohm (?) series resistor and the 20k ohm (?) volume potentiometer.
That would be fairly primitive?

ETA >> now I think about it;

the first thing I did with my Lepai, having read a 'strip-down review', was lift the lid (nixing the warranty! On no!) and check the heat-sink - it had a dot of thermal-paste about 0.5 cm across which I cleaned off, then re-applied fresh stuff.

(You can carefully bend the TA2020 away from the heatsink, which is soldered to the board via 2 through-holes - at least, it is on my recent example.)

Anyway, I'm pretty sure the pot on mine is 10K. I'll have another look and confirm or otherwise at some point.

ETA 2 >> you have to pick off the hot glue which secures the two steel clips which clamp the TA2020 to the heatsink before you can remove them. I guess they apply this in case the amp is used in an environment where it's vibrated ("car, bike, boat").

Last edited by Aleksunder; 21st July 2013 at 07:50 PM.
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Old 21st July 2013, 07:57 PM   #1618
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Let's clarify;

The heatsink is attached to the board via 2 legs which are soldered like through-hole components (but more solidly).

The TA2020 chip is also through-hole soldered, and is then clamped to the heatsink with 2 u-shaped steel clips.

It's worth checking that the TA2020 is actually intimate with the heatsink, via a proper layer of goo.
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Old 22nd July 2013, 12:46 AM   #1619
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For significant improvement to the Lepai, a friend of mine, armed with the right tool, managed to desolder the stock surface-mounted JRC 4558D opamp and replaced with a LM4562 with very good results.

Personally, I don't think changing the heatsink or reapplying the heatsink compound makes any difference. After all, the Tripath TA2020 runs cooler than most Class AB chipsets (some Class AB amps doesn't even utilized a heatsink!). I won't go the extra mile if the tweak doesn't improve sound quality.

As for the NSMT-modded Lepai, nice wood case and binding posts. However for US$90, I don't think is worth it. Many of the DIYers in this forum can do a better job for much lower price.

Last edited by KopiOkaya; 22nd July 2013 at 12:58 AM.
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Old 22nd July 2013, 02:40 AM   #1620
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Well.... to be fair the "$99.00 upgrade" includes better power supply.
or you can just get this one: Universal Laptop Power Supply w/USB 4.2~24 VDC 70 Watts 120-500
or this one and possibly change the plug:
12 VDC 5A Switching Power Supply with 2.5 x 5.5mm Plug 120-056
more "A" to the amp - better it sounds...less distortion at higher volume...
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