Lepai T-Amp with TA2020

[raz]

Originally Posted by raz

Hi, i have bought 3 Lepai TA2020 amps and they have all broke .
I have hooked them up to a car battery some 4ohm speakers and a mp3player. It all sounds great until I turn up the volume and the amp breaks. After that all i get out of it are some clicking sounds and the led light.

Since there are no fuse i have no idea what's broken inside. Have anyone encountered the same problem? is it fixable? or should I just buy yet a new one?

Originally Posted by vzon

No I was just sharing info an adding capacitors. not as a remedy for your non working ones. I had one of my amps blow also a couple weeks ago. I think its just from puttting in to strong of a signal in some cases.

Well, im kind of new to all this... im using all of this for a "boombox" and i kind of need an amp that dosen't blow out on me every time i turn the volume up. Is there some thing i can to hinder this happening again, if i buy a new one? 3 amps in 2 week is a little to much i think.

Could i put a resistor on each channel before the input to the amp or maybe a 200mA fuse? ides anyone?

[col]

Originally Posted by raz

Well, im kind of new to all this... im using all of this for a "boombox" and i kind of need an amp that dosen't blow out on me every time i turn the volume up. Is there some thing i can to hinder this happening again, if i buy a new one? 3 amps in 2 week is a little to much i think.

Could i put a resistor on each channel before the input to the amp or maybe a 200mA fuse? ides anyone?

If you bothered to read this entire thread you would already have the answers. First you need to remove the little orange zener diode that is just in front of the chip. Second, don't allow the input voltage to go above 13.2v.

col.

[raz]

Originally Posted by col

If you bothered to read this entire thread you would already have the answers. First you need to remove the little orange zener diode that is just in front of the chip. Second, don't allow the input voltage to go above 13.2v.

col.

Hm.. The ticking stop when i removed the zener diode but still no sound. I don't know if it input volt was over 13.2 though, i don't have a mulitmeter.

All it dose now is make a sound when i turn it on an then go quiet.
to bad...

[col]

If it was "ticking " it is already dead. Removing the diode is for prevention not a cure.

[engelhornc]

I bought a pair of these a few weeks ago. One is for a friend who needs a small amp in his diesel rock-hauling truck so he can hear his Garmin. The other is for the back patio of a small restaurant here in town. Mine came with some "2A" power supplies - but I'm guessing they'll never deliver 2 amps unless they dead short to the mains... but I digress.

Out of the box these little amps sound pretty good, and they're not "terribly" built. Not too terribly, anyway. I read this thread a few times so I was prepared to fix a few things.

For my friend in the truck - well, he can plain live with the unit as delivered.

For the restaurant... well I thought I'd implement a few of the fixes and see how things work out before I get my own unit.

1> replaced the opamp with ne5532.
2> fixed the tone control component values, thanks DrLex.
3> replaced the input caps
4> fixed the wacked DC offset to the speakers, 60mV and 140mV..
5> found a 4.5A 12V switching supply and set it to 13.3V output voltage.
6> ordered some 10uH toroids... but this is the last fix I'll do on this unit.

I used ZZ Top's "Tres Hombres" and "Fandango" as my test music. There are some great transients (La Grange), good bass lines, and mostly I'm familiar.
The frequency responce irritated me right off the bat, as did the fact that the puny power supply was obviously farting out whenever I pushed the amp at all. The bass and treble controls just seemed like weird filters... yes they adjusted the bass and treble regions, but I couldn't get anything near a flat response to my ear.

After the fixes (and I'm still anticipating a bass improvement with the new toroids) I have to say that this is a really fun little amp. The tone section is usable, the power level is impressive, and most importantly I really enjoy listening. Oh - my test speakers are just ok - a pair of Madisound "Recession Busters" from last year.

I'm going to buy another one and mod it for myself. I have a set of Klipsch La Scalas down in my garage and I'm eager to put a little Ipod, this little Lepai, and those big ol' speakers together. No one will believe it.

Thanks for the great info!

Craig

[col]

Craig,

Don't forget to remove the little zener diode. If the amp develops a fault the diode puts it into a reboot loop and the amp burns out. Thats the "ticking" people are reporting when their amps die. Also, it's worth changing the pots if you can find some that are a drop in replacement. The stock ones are all over the place (read DRLex posts).

My Lepai sounds awesome, It's best to use with over 90db efficient speakers.

col.

[raz]

Im new to all this and find it really intresting. I have a car battery that will power my Lepai. So my question is if there is a easy way to make circet that feeds the amp 12v since a car batttery can give out well over 13.

[col]

you should be fine if you check it with a multimeter first and don't charge it to over 13.2v or you could drop some voltage using a diode or a regulator. I use mine on a 12v SLA that will charge to over 13.2v if I don't watch it.

col.

[j0ckinjz]

Someone should put together a nice tutorial of all the mods done to this amp... so people like me can understand what to do lol

[raz]

I know! it would be quite nice with a tutorial.