I have one of these running in my home. This unit sound better with tone control, else it sound really dull.
The high is muddle & lack of bass. Definitely not flat.
No mod on this unit yet.
I suspect the tone by pass is affected by the input cap, resistor and out inductor.
If change all components, I'll opt for the better amp selling out there.
I bought this for budget concern.
The high is muddle & lack of bass. Definitely not flat.
No mod on this unit yet.
I suspect the tone by pass is affected by the input cap, resistor and out inductor.
If change all components, I'll opt for the better amp selling out there.
I bought this for budget concern.
I replaced the stock 4558 op amps in mine with some SOIC LM833s I had in my parts bin. The bad news is that I get noise ("hiss") when the volume is set between about 9 and twelve o'clock and I engage the tone circuit. Then it totally disappears at about 1 o'clock. I can live with it for now. I'm feeding a multi-amp setup thru a distribution preamp with it's own volume control, so the noise isn't a big issue right now. And it doesn't exist at all with the tone disengaged. The good news is the fidelity is improved and it put the reins to that gawdawful high-midrange squeal. I'm running it into a pair of RS Pro LX5s with Peerless 5-1/4" woofer replacements.
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my experience is opposite, want to be able to disable or take out the tone-control all together, waiting for a simple "upgrade" if someone can give a pictorial lesson (not too good with schematics).
You are both referring to post #736. It shows the older schematic with the tone circuit but no defeat switch. gychang, I'm not too good with pictorial lessons. But if you look at the schematic, you'll see that you can bypass the tone circuitry by removing C4 and C2 and placing a 2.2uF capacitor from the C4 negative pad to the C2 positive pad. Do the same with C5 and C3 of the other channel. Be aware that the designators (C4, C5, etc.) are probably different on the newer model, but the mod remains unchanged. Use C9 and C10 instead of C4 and C5 if you want to keep the op amp preamp gain.
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If you have the bass maxed all the time and it still isn't enough, I would look at the system as a whole. What kind of speakers are you using? Honestly, I played mine thru some 8" FR and the bass was insufficient. But I never intended to use it without a subwoofer. Have you considered adding a sub? You might be able to gain some low end by changing some caps and/or tweaking the tone circuit, but IMO you'll get better results with a sub. Even 15WRMS is plenty with the Lepai driving 4 or 8 ohm speakers.
I just got one of these amps for the hell of it and I had it hooked up to some Polk Audio RTA8TL's ( 6.5" MTM ported) and I was surprised how much bass this little tiny amp put out. It actually sounded better than a Sony ES 2 channel receiver that i had them hooked up to before. Although the Lepai cost $20 more than the Sony 
Lepai Amp and Polk Audio Speakers
Hello, I have a question regarding a computer-bookshelf-speaker-setup.
I'm thinking of getting Polk Audio Monitor 30's series II and a Lepai LP-2020A+ amplifier from Amazon.com (shipped and sold by Parts Express). My question is:
Will this amp be able to handle these 8 ohm speakers efficiently? I won't be blasting these speakers at loud volumes.
All in all, is this a recommended amp for a small computer speaker setup?
Thanks
Hello, I have a question regarding a computer-bookshelf-speaker-setup.
I'm thinking of getting Polk Audio Monitor 30's series II and a Lepai LP-2020A+ amplifier from Amazon.com (shipped and sold by Parts Express). My question is:
Will this amp be able to handle these 8 ohm speakers efficiently? I won't be blasting these speakers at loud volumes.
All in all, is this a recommended amp for a small computer speaker setup?
Thanks
I haven't heard the Polks, but my short answer would be yes.
The specs show a low -3db point of 63Hz and recommended amp power of 20-100W, so I wouldn't expect big bass from the setup. See my last post regarding subwoofers - for me it helps immensely. I usually listen between low 90s (dBC) and high 6os (when I go to sleep). I can play my system all day and all night. It sounds fine at either extreme and never fatigues.
The specs show a low -3db point of 63Hz and recommended amp power of 20-100W, so I wouldn't expect big bass from the setup. See my last post regarding subwoofers - for me it helps immensely. I usually listen between low 90s (dBC) and high 6os (when I go to sleep). I can play my system all day and all night. It sounds fine at either extreme and never fatigues.
Thanks for the reply.
I'm not expecting nor looking for "big bass". I simply want a nice pair of inexpensive speakers that will sound good.
Unless you mean they won't have "big bass" because the speakers are being limited by the Lepai LP-2020A+ amplifier.
I tried cyber-acoustic speakers which came with a 5-1/4" subwoofer (that's right, they classified a 5-1/4" driver as a subwoofer) but it sounded to muddy and the satellite's alone sounded like tiny metal cans.
I also looking at these: http://www.amazon.com/Dayton-B652-2-Way-Bookshelf-Speaker/dp/B002RMPHMU/ref=sr_1_1?ie=UTF8&qid=1313100439&sr=8-1
They may do the job but I am an audio purist and I've had experience with Polk Audio speakers already. Which is how I ended up with the Monitor 30's Series II.
I'm not expecting nor looking for "big bass". I simply want a nice pair of inexpensive speakers that will sound good.
Unless you mean they won't have "big bass" because the speakers are being limited by the Lepai LP-2020A+ amplifier.
I tried cyber-acoustic speakers which came with a 5-1/4" subwoofer (that's right, they classified a 5-1/4" driver as a subwoofer) but it sounded to muddy and the satellite's alone sounded like tiny metal cans.
I also looking at these: http://www.amazon.com/Dayton-B652-2-Way-Bookshelf-Speaker/dp/B002RMPHMU/ref=sr_1_1?ie=UTF8&qid=1313100439&sr=8-1
They may do the job but I am an audio purist and I've had experience with Polk Audio speakers already. Which is how I ended up with the Monitor 30's Series II.
I mean both together. It's next to impossible to get lower bass octaves from a bookshelf speaker, and the Lepai is a low-powered amp that can't provide the energy needed. Believe me, you don't want to listen to the Lepai at it's rated 20 or whatever watts.
The Daytons are much less $$ than the Polks, so you could use that extra money for a sub. A 5-1/4" driver is what it is. There's nothing wrong with one in a well-designed sub.
Hmmm... well, I am not. Audio for me is not a quest, it's just a journey. Any talk of "purity" contradicts this entire discussion IMO.
there are several different versions of Lepai, I took some pictures of mine and considering upgrade steps suggested on this forum: Modding the Lepai T2020A+ - Techtalk Speaker Building, Audio, Video, and Electronics Customer Discussion Forum From Parts-Express.com
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Yes, that's the Lepai version I have. I only replaced the op amps with LM833s and repaired the RCA input ground pin that I accidentally broke when it was out of the case. It got rid of the worst distortion I was hearing so it was a mod well worth the time for me. I've seen stuff like "the output coils aren't big enough" but they're the same as the ps input coil so there must be more to that story. Upgrading caps certainly couldn't hurt. Or increasing the values of the 3! coupling caps. Some of those might even be replaced with jumpers, but I would double check DC measurements and tolerances before attempting that.
I basically working from the assumption that the schematic posted a while back would apply to this version, less the tone switch. I didn't ohm out the switch or much of the board. I chose not to spend too much time and money on a $20 amp.
I basically working from the assumption that the schematic posted a while back would apply to this version, less the tone switch. I didn't ohm out the switch or much of the board. I chose not to spend too much time and money on a $20 amp.
I got one of these little amps from Parts Express.
I needed some Tolex and a few other parts to finish some guitar speaker cabinets that will be seen in the Hundred Buck Amp Challenge thread.
http://www.diyaudio.com/forums/instruments-amps/190738-hundred-buck-amp-challenge.html
Parts Express wanted $13 to ship my order, but If I spent $18 more I would get free shipping. I guess that made the amp cost $7. SO.....
I brought a chip amp to a tube fight. I have been listening to a Tubelab SSE running KT88's in single ended triode mode making about 8 WPC. For really annoying the neighbors I have Pete Milletts red board making 125 WPC. The speakers are Silver Iris 15 inch coaxial drivers mounted in old Zenith console radios. They are 96 db efficient making them loud enough to hear across the street with the 8 WPC SSE. The 125 WPC amp is rock concert in the living room loud.
I hooked up the Lepai and cranked it up. It sounded much better than I expected right up to the point where the sound instantly turns to mud.....Digital Clipping sucks. "20 WPC" of digital amp is not as loud as 8 WPC of tube amp because you can run the tube amp into clipping without putting your fingers in your ears. Unlike some other posters I have plenty of bass with 15 inch woofers. I played with the tone controls trying to match the tube amps sound at a volume level well below clipping. I wound up with the bass knob at 10 o'clock and the treble knob at 2 o'clock.
For $7 it is a keeper, and I would probably buy one for $20. It will wind up as the amp on my PC for those times when I don't feel like pumping 100 watts worth of heat into the room. Here in Florida, that is 90% of the time.
I don't know why, but my unit came with a Vonage power supply that has obviously been used, very used. It seems to work OK and the LED doesn't blink even when the amp is heavilly hammered into clipping. Wonder what will happen if I play my guitar through this thing.
I needed some Tolex and a few other parts to finish some guitar speaker cabinets that will be seen in the Hundred Buck Amp Challenge thread.
http://www.diyaudio.com/forums/instruments-amps/190738-hundred-buck-amp-challenge.html
Parts Express wanted $13 to ship my order, but If I spent $18 more I would get free shipping. I guess that made the amp cost $7. SO.....
I brought a chip amp to a tube fight. I have been listening to a Tubelab SSE running KT88's in single ended triode mode making about 8 WPC. For really annoying the neighbors I have Pete Milletts red board making 125 WPC. The speakers are Silver Iris 15 inch coaxial drivers mounted in old Zenith console radios. They are 96 db efficient making them loud enough to hear across the street with the 8 WPC SSE. The 125 WPC amp is rock concert in the living room loud.
I hooked up the Lepai and cranked it up. It sounded much better than I expected right up to the point where the sound instantly turns to mud.....Digital Clipping sucks. "20 WPC" of digital amp is not as loud as 8 WPC of tube amp because you can run the tube amp into clipping without putting your fingers in your ears. Unlike some other posters I have plenty of bass with 15 inch woofers. I played with the tone controls trying to match the tube amps sound at a volume level well below clipping. I wound up with the bass knob at 10 o'clock and the treble knob at 2 o'clock.
For $7 it is a keeper, and I would probably buy one for $20. It will wind up as the amp on my PC for those times when I don't feel like pumping 100 watts worth of heat into the room. Here in Florida, that is 90% of the time.
I don't know why, but my unit came with a Vonage power supply that has obviously been used, very used. It seems to work OK and the LED doesn't blink even when the amp is heavilly hammered into clipping. Wonder what will happen if I play my guitar through this thing.
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I agree, simple mod is what I am after. Which part exactly on the picture, and where can I get the replacement part?, (web page).
thanks in advance.
The parts I replaced are U1 and U2, the two 8-pin surface mount ICs just above the volume pot in your first picture. I had LM833s handy so that's what I used. Popular audio op amps like the NE5532 and OPA2134 ought to work also. Here is the 5532 page from Digi-Key, but these parts can be obtained most anywhere finer electronic components are found. I didn't take time to measure but just went on the supplies being the split 12VDC input. There's lots of +/-6V op amps to choose from these days.
I've posted some other tips and caveats from my experience going back in this thread a month or so. Nothing too involved, challenging, or expensive. I think it's established that with a good pair of speakers, this little amp can provide quite satisfying listening. Good luck with yours and keep us updated on your progress, questions, and listening opinions.
I've posted some other tips and caveats from my experience going back in this thread a month or so. Nothing too involved, challenging, or expensive. I think it's established that with a good pair of speakers, this little amp can provide quite satisfying listening. Good luck with yours and keep us updated on your progress, questions, and listening opinions.
Yes, in a well designed sub, but why bother getting a subwoofer with a 5-1/4" driver in it? If you (me in my case) were to by a subwoofer would you put down $80-200 for a well designed "mid-range driver"? I'd want to get something with some good clean, tight, rattle the room bass. That require's a somewhat larger driver than 5-1/4"; however, to make it simple, I don't want a subwoofer. I want a 2.0 setup and for the simplest reason in the world, money. I'm 16, I don't exactly have a general surgeons payroll.
The Dayton's are cheaper because they do lack bass and clarity from what I've read. I trust Polk Audio, they've done nothing but impress me with their speakers.
Audio is not a quest for me either, but I'm not going to buy the cheapest look set available on the market. That's all I was getting at.
It all comes down to one thing, do you believe the Lepai will be bottle-necked by the Polk Audio Monitor 30's Series II? I like clean, tight bass. Shouldn't this amp be able to produce that?
No hard feelings. Thanks for responding.
Because there is a need for it, and it's well-designed.
If you think you can match that output with the Lepai and the Polk speakers, let no one stop you. I've been contemplating a 2nd sub for my system, diy style.
Duly noted. I wouldn't intentionally steer you wrong.
I mentioned the Dayton's in the context of running them with a sub. If you just want 2.0, the Polks are fine and at a great price. I have some Polk speakers on another PC, and heaven knows I've gotten lots of mileage out of them.
Sorry, I never meant to imply anything of the sort. My point was just that if we're gonna talk purity, the Lepai needs to be coupled with a very efficient pair of wide response speakers. Big budget speakers mostly.
I agree it should. It and thoughtful speaker placement can go a long way IMO.
Not at all. Sorry if I seemed to antagonize. The Lepai sounds surprisingly good when kept below clipping. It should drive the Polks to moderate SPLs. Probably not rattle-the-room SPLs, but a decent system that you can live with and expand upon. Let us know how it comes together.
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