@sofaspud: Thanks for the response. Based on your ideas, I know I don't want to learn that much about this just to get this amp working. Will take your advice and simply get a new amp. Boom zap problem solved. Thanks!
Hey! I plugged it into a 12v wall wart, and it works! Beautiful! Great sound! It's beyond my understanding, but I don't care, cause it works. Lepai 2020+.
HI there,
I ordered a replacement TA2020 IC... still waiting for it to arrive...
In the meantime, I was wondering whether it's possible to find a suitable socket for the IC to allow for easy replacement in case of a future failure... saves having to desolder the old chip, and solder on the new one.. each time (hopefully never again... but you never know!)
In the datasheet, it mentions: 32-pin SSIP package
Not sure if that helps. Anyone have any ideas whether it's possible to find a suitable socket for the IC?
Cheers,
Pete
I ordered a replacement TA2020 IC... still waiting for it to arrive...
In the meantime, I was wondering whether it's possible to find a suitable socket for the IC to allow for easy replacement in case of a future failure... saves having to desolder the old chip, and solder on the new one.. each time (hopefully never again... but you never know!)
In the datasheet, it mentions: 32-pin SSIP package
Not sure if that helps. Anyone have any ideas whether it's possible to find a suitable socket for the IC?
Cheers,
Pete
I have 2 sitting on my desk, I am interested in improving the sound, so I am waiting for a guru to guide me. Would appreciate your input and have the solder gun warmed up...
For a guys like me picture-guide work wonders...
Those acronyms again... I think SSIP is Staggered Single In-line Package. I am not aware of a socket for these. You could possibly make one by using two single-row headers. Sometimes sockets are a definite bad idea, though, and this may be one of those times. To replace the bad chip, just cut the leads of the chip. Then it's pretty easy to heat the remaining legs and push them out of the holes. Clear the holes of solder using a solder sucker or by melting the solder and then giving the board a light tap on the benchtop.
I don't consider myself a guru. I have been doing plenty of listening. I have my Lepai connected to a pair of modified RS Nova-10 speakers. The passive radiators have been replaced with 8" full-range drivers, with their own small chip amp. I'm also using a small sub and the sound is surprisingly good. Without the sub the Lepai seems to lack low-frequency power. It'd be nice to stretch another octave or so out of the low end. I've been busy lately (need to leave now to go meet with a customer) but I'm sure I have some caps and op amps on hand. That's where I plan to start unless I find something else when I get my amp opened. More to follow.
Unfortunately the LP2020A+ I have is identical to the pic of post #751 and not like the schematic of post #736. In the pic (just south of the RCA inputs) R36 & R37 are 1k series resistors and R34 & R35 are 10k resistors to ground. C30 & C31 are 1uF input coupling caps. From there the signal goes to the 20k potentiometer then right to the op amps, so it looks like at least part of the flaky tone circuit could be caused by the bypass implementation. Hopefully the circuitry from there on is close enough to the posted schematic.
I wasn't very familiar with the 4558 op amp, but everything I see (and hear) says this thing is just a glorified 1458, ie no way suitable for audio. That's the first thing I'm going to address on my Lepai. I have some SMT LM833s in stock and that's what I'll use. Not my first choice but they are at hand. Hopefully that will clear up my main issue, which is the midrange distortion I get at higher volume. My speakers lean toward the bright side anyway, and that distortion makes me want to run for cover. Horrendous!
If you own a soldering iron, you can do this too. Just cut the legs of the 4558 with an Exacto. The parts remaining will probably stick to the iron tip, making removal easy. Then clean the pads with desoldering braid. Put a small amount of solder on one pad, then use that pad to align the new chip and tack it down. Then solder the rest of the leads using plenty of flux.
If you own a soldering iron, you can do this too. Just cut the legs of the 4558 with an Exacto. The parts remaining will probably stick to the iron tip, making removal easy. Then clean the pads with desoldering braid. Put a small amount of solder on one pad, then use that pad to align the new chip and tack it down. Then solder the rest of the leads using plenty of flux.
OK, I connected mine to a variable power supply, if the supply voltage goes below about 8.5V the amp is muted and the fault pin goes high (I have an LED connected to the fault pin). When the voltage goes above 8.5V the amp comes back on and the fault pin goes low.
I can't think of any reason why running only one channel should damage the amp. If your using it for a sub woofer, you could use a dual voice coil speaker and connect both channels to increase the output.
Any chance of getting a picture? 😉
I am unable(/an idiot) to read those layouts, would it be possible to help out a noob and show a real picture? 🙂
I'm planning to run this of a 8 pack AA batteries - any chance I will kill it? (ie. go over 14V?)
I am running my A+ from 10 AA NiMh cels without a hitch. The measured voltage across the pack fully charged was a little over 14V but this dropped away to under 14V on switch-on.
Tim.
I can't seem to get my Lepai amps to output any sound. I'm using a 12V SLA battery as power supply. And when I power on the amp the diodes are looping from 100% on to maybe 75% and back to 100%. Is it supposed to do that?
When I power them with a small 9V battery instead, the light from the diodes are constant but still no sound output. I've tried both the RCA and MP3 inputs and three different Lepai amps, all the same problem. I heard that you are supposed to hear o click or pop when you put it on, I don't get that, it's dead silent.
What do you think might be the problem?
When I power them with a small 9V battery instead, the light from the diodes are constant but still no sound output. I've tried both the RCA and MP3 inputs and three different Lepai amps, all the same problem. I heard that you are supposed to hear o click or pop when you put it on, I don't get that, it's dead silent.
What do you think might be the problem?
Are you sure that you have powered them with the positive to the centre pin? The Lepai amps have no protection against reverse polarity. Reverse polarity destroys the Tripath chip immediately.
Well, all I can say is you should return what has failed to the sellers. You don't need me to say this!
The community would like to hear how you get on.
Regards,
T.
The community would like to hear how you get on.
Regards,
T.
Technically that's only open voltage of standard alkalines. Under load they're around 1.2V each, so you'd actually need 10 in series to get you desired 12V operating voltage.
(It's also why NiMH batteries work fine as replacements even though their nominal voltage is only 1.2V. They maintain that voltage under load.)
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Yes, this is all true, but if the IC sees 15 volts for even a second, then it's all over...
Nope. Absolute maximum rating of the chip is 16V. It should not be operated under that voltage but it will survive, in fact, I had a TA2020 survive 19.2V as well.
Maximum operating voltage is 14.6V, btw.
For those interested, this is a picture of the newest board (dual opamp and tone bypass).
There is no component underneath.
Thanks for the photo. Has the newest board with tone bypass been measured?
So now we are just left with the minor tweaks - power supply capacitors, output inductors, resistors and capacitors (replacing with better quality parts)?
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