Weird But Practical - Leper Amps!

No matter how you spell it or pronounce it, they can be quite useful - with some modifications and routine maintenance. Just a note that the model 2020A that you find is not the same as the 2020A+.... Enjoy!
#franlab #lapai #lepy
- Music by Fran Blanche -

[Torby]

Hehe Most would have said, "These things are junk" and tossed it. Fran figures out how to fix it. That's why we love Fran.

[wphanoo]

I absolutely love them. Perfect sound quality, no noise (contrary to some Genelec I tried), supe reliable.

[YodaWhat]

When the idea of a Switching Amplifier occurred to me, back in 1986, I made one very simply from a CMOS 555 timer chip, one low-pass output choke to average out the square waves (while especially killing their sharp edges), one external transistor (to give a 50% duty cycle on the square wave output), small caps and resistors to set the oscillator, plus a small pot to tweak the free-running frequency. I set it to oscillate at close to 2 MHz, adjusted so that none of the square wave harmonics would be in the AM Radio band. This also put any residual square wave noise far above the human audio range. Nyquist sampling rate (nearly 2 MHz) was very high, giving very good wideband frequency response. *Audio Input was to the **_analog_** PWM pin, * through a small cap for DC blocking. It was only monaural, but it put out very good audio with no detectable DC offset, about half a watt while running on 5 volts, and there was no sensible heat generated. If it had half of a MOSFET H-bridge added to the output, it would have been able to run cool at high power.

[valpine]

One thing I like about the tripath 2020+ is when driven to just barely clipping. They do not sound harsh at all like most class-D chips when overdriven slightly. More like tube-fuzz if that makes any sense.

[ertyuiiknbvcx]

I read on forums when i bought this Lepai that the Tripath history was that it is chips made for really high-end amplifiers, but that the company got bankrupt and heap loads of chips sold for nothing ended up in cheap amplifiers from China. The 2020A+ is a great amplifier for sure :)
I did mod the 2020A+ with ring core chokes, i cut away the crappy preamp chips, i cut away the tone controls because i like the source unmodified, and cut away the stock input electrolyte capacitors, in other words i bypassed everything with only i think 0.22uF film caps between the chip and RCA plugs, and the sound improves alot like high end stuff shall be. It was descriptions and inspirations on the internet for these mods.
Also use a stronger power supply than the stock ones, it need more power for bass when playing loud. I think i used a ancient laptop PSU for this purpose.
I still got this old Lepai.
I also did modify it with warm nice orange LED's with the right resistor to adjust the light, it is really nice now compared to the stock blue ight it had :) I tested first with warm white LED's, it was okay'ish, but not enough, so i found orange to be even better :) My first chrome and teak cased germanium transistor Philips amplifier i had as a kid had orange power light on it so i wanted to copy that idea :)
I use it with a Eltek kit build DIY (cut MDF plates yourself) speakers, with SEAS speaker elements (Norway's best speaker factory), alu tweeter on it i think H400, and modified removed dustcap & cut spider on the speaker element, for mid/bass, a description for making the speaker more freely moving with more details in the sound.
I also bought some other lower powered Tripath's too as spares back in those days, the thought was if i ever needed something in my car or home. It is said that the smaller ones shall have a warmer sound to it, almost tube like compared to the 2020A+, not 20 watt like the Lepai but i think 15 watts, great for low sound (to get the distortion figure down properly) near field listening. Shall we see, yes Tripath TA2024 chips it is in these.
Search TA2024 on ebay and you still get these dirt cheap, with even nice red audiophile caps on the green PCB already installed, so perhaps try them out instead of these shitty new Lepy ones? :)
I read that some people even prefer these smaller ones, because of the warmer sound, if they usually listen to music not so loud and near field.
I also bought two stronger than the 2020A+ Tripath amps on PCB, TK2050, to make something some day perhaps for the car.
I has not tested any of these yet because the 2020A+ covered my needs so far.
I also has two different kit build 6N3 tube preamp buffers if i like the tube sound anyway. The ones with 2x 6N3 tubes gives weakly warmer still neutral sound, does not change the sound much.
While the i think the starved one 6N3 tube PCB gives very warm sound, and, in some cases i like this one :)
That is if i want warm sound like my 1945 Tandberg Sølvsuper 4 (Silversuper 4) radio i had as a kid, i for sure get it with that one, if not more, yeah, too warm sound gives me something if i want my ears to relax from modern music :)

[terrypussypower]

5:13 “Dying by inches for years”! That’s the story of my life!

[scottrobinson]

I had two of those on my work bench, at a sound company I worked for... Just used them for function testing on a variety of speakers, as they came back into the shop from being out on rentals.

[robrain]

OMG as soon as i saw the title i was like i have been using that same one on my system forever. For the price there great.I use my old Denon surround speakers .Have a great day.

[SlowMenThinking]

Yep Those Tripath amplifier modules can produce some very pleasing amplification and seem to be able to drive some interesting impedances. I have been using an amp with the module to drive the near field monitors I use for recording/mixing as well as taking a set of floor standing speakers and an amp to do an AV upgrade for a viewing at other peoples places! No it won't produce enough volume for a very large space with some speakers (even a 200W class A/B will struggle with the wrong speakers!) Some say they are good for the price the reality is they are just good...

[CarlVanWormerAEGD]

I'd be interested in a test of the new (smaller chip) system . . . chip temperature - vs. - power output.

[WilliamGrout]

I have used several of these "original" amps for many years and have been very impressed with the build quality and longevity for the price point. Most of them came with a minimal power supply and will do much better with more amps in.

[dhpbear]

3:31 - Adding a capacitor between the switch contacts should minimize damage from arcing.

[OregonDARRYL]

Kinter Tripath 2020 IS available now for about 45 bucks on Amazon. I bought one and it sounds great.

[chriscordingley]

Latest Texas Instrument chips are amazingly efficient. 20W in a 4mm x 4mm package !! The fist amp I built 50 years ago had a heatsink which was a tray which I filled with beer at the Disco! The beer would boil! 😀

[guitarfreak]

Fran is right these little amps are great for TV, computers, and bedroom size stereos.

The one I have is pretty nice. It has USB and Bluetooth. The downside is the remote sucks! Even with a fresh out of the pack battery you have to be 2 feet away from the amp, in order for it to work.

[Nu]

I bought and still have that same Lepai purchased for less than $30 about 10+ years back and it has been competently driving a pair of Polk 2way bookshelf speakers ever since. The only downside has been that dodgy power switch which doesn't make full contact on every power up.

[rotaxtwin]

I'm amazed at how well these little Class D units work, the punch they pack and the sound quality. I've had a little unit running on a laptop power supply (19.5V @ 5A) running on our 'main system' (living room PC & TV) and when the sound effects start flying it will shake the house. Very impressive.

[rogeliorodriguez]

OMG that amp...We used to have a chinese restaurant and it always humored me to see that little amp playing music in the dining room, it sounded pretty good, but the most amazing thing, It always seemed to be on and I went there for 15 years before they finally went out of business.

[ironfront]

I hooked up a 2.1 version of these to a franken mix of 2x hifi floorstanding speakers and a large 2ohm car subwoofer and amazing the amp drove the setup, including the sub, extremely well. Could get the whole room shaking and it wasn't noticeably overheating.

[rhalfik]

Class D is not only more efficient, but also can be hifi. There are highend class D amps that have as little distortion as class A, except at higher power and better efficiency. Purifi and Hypex for example.