You hit the nail on the head. I think I'll purchase the speakers and Lepai amp, but one more thing, I've heard remarks that the Lepai makes a loud "pop" sound when turned off (and on?), should I be worried about this?
From what I've seen and experienced, this was a problem with earlier versions of the Lepai (the thru-hole models in particular). But there seems to have been some redesign and it is no longer an issue. I've never experienced the on-off thumps with mine. Apparently the first? fix was simply to put the Tripath chip in standby mode when switched off, leaving power to (most of) the rest of the circuit. Whether that remains the case I don't know. I haven't taken a DMM to mine. I think they use a relay delay on the outputs now, though.
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Just bought a 2020+ for a trip to the desert in about a week. Will be running off 12V SLA battery. The amp sounds pretty good & loud in my apartment, driving an old set of Cambridge Soundworks Ensemble II satellites + sub. 6 ohms - I'm not sure what the sensitivity is, but I don't think it's very good. But I can't take these speakers with me to the desert...
Can anyone suggest speakers that are 1) efficient / low impedance, 2) cheap? (Like really cheap - less than $100 pair, used is o.k.) I'd like to find something that sounds at least as good as these Cambridge sats/sub, with equal or better bass & volume when driven by the Lepai.
Can anyone suggest speakers that are 1) efficient / low impedance, 2) cheap? (Like really cheap - less than $100 pair, used is o.k.) I'd like to find something that sounds at least as good as these Cambridge sats/sub, with equal or better bass & volume when driven by the Lepai.
Replying to myself, since edit window seems to have expired.
How about something like this: Amazon.com: Pyle-Pro PADH879 - 300 Watt 8'' Two-Way Speaker Cabinet: Musical Instruments Pyle Pro PADH879
8 ohms, but the sensitivity seems good. A reasonable choice for outdoor use?
Or these: Amazon.com: Pyle Home PDWR50B 6.5-Inch Indoor/Outdoor Waterproof Speakers (Black): Electronics
4 ohms, 95dB
How about something like this: Amazon.com: Pyle-Pro PADH879 - 300 Watt 8'' Two-Way Speaker Cabinet: Musical Instruments Pyle Pro PADH879
8 ohms, but the sensitivity seems good. A reasonable choice for outdoor use?
Or these: Amazon.com: Pyle Home PDWR50B 6.5-Inch Indoor/Outdoor Waterproof Speakers (Black): Electronics
4 ohms, 95dB
I have it on good authority that you want the The Boominator - another stab at the ultimate party machine thread.
Thanks for the reply. But isn't that thread specific to projects using separate drivers and building them into a homemade cabinet? Unfortunately, I don't think we've got the time to do any of that... Hence the question about pre-built speakers / PA cabinets that would pair well with the Lepai 2020.
Tone control mod for center-level response.
There are a lot of comments on the tone controls in the original LP2020 degrading sound quality, and an analysis shows why - The component values are weird. In fact, with the original model's values, no control setting gives a level response. Putting textbook values in makes a huge difference to sound quality, even without bypassing the tone stack.
Bass control:
Change the 47n pair (green, between pots) for 100n
Change the 1.5k pair (behind the bass pot) for 1k.
Treble control:
Upper capacitor should be 1n, lower cap should be 10n.
These are usually OK. But, check.
On the TA2020's opamp input pins 9/10/12/13:
Change the 8k2 pair for 27k
Change the 22k pair for 68k
These should be metal film to keep noise low. They are located in two pairs between the pots and the chip.
You can experiment with the rolloff frequencies by changing the caps, just keep them in a 1:10 ratio for correct action. For a finer adjustment range with good speakers you might prefer 470p/4n7 and 22n/220n.
Not sure if this applies to the new SMD model as I don't have one yet.
BTW, if you have a bad switch-on thump, ohmmeter the ground lines under the chip for cracks. Particularly the one which goes via a heatsink mounting lug.
There are a lot of comments on the tone controls in the original LP2020 degrading sound quality, and an analysis shows why - The component values are weird. In fact, with the original model's values, no control setting gives a level response. Putting textbook values in makes a huge difference to sound quality, even without bypassing the tone stack.
Bass control:
Change the 47n pair (green, between pots) for 100n
Change the 1.5k pair (behind the bass pot) for 1k.
Treble control:
Upper capacitor should be 1n, lower cap should be 10n.
These are usually OK. But, check.
On the TA2020's opamp input pins 9/10/12/13:
Change the 8k2 pair for 27k
Change the 22k pair for 68k
These should be metal film to keep noise low. They are located in two pairs between the pots and the chip.
You can experiment with the rolloff frequencies by changing the caps, just keep them in a 1:10 ratio for correct action. For a finer adjustment range with good speakers you might prefer 470p/4n7 and 22n/220n.
Not sure if this applies to the new SMD model as I don't have one yet.
BTW, if you have a bad switch-on thump, ohmmeter the ground lines under the chip for cracks. Particularly the one which goes via a heatsink mounting lug.
Additional thoughts..
You can use this 'center-level' mod with DrLex's tone stack if you prefer.
In that case, retain DrLex's values and only change the TA2020's opamp input resistors:
8k2 pair for 47k (instead of 27k)
22k pair for 120k (instead of 68k)
Reason; the 10k center resistor demands that these values also be higher.
Superbass mod: If the bass range is still insufficient, for each channel handwire a 10n capacitor and 150k resistor in parallel, and then place this assembly in series with one end of the 20k/22k feedback resistor of the 5532 preamp.
Not one for the purists but makes for a much rounder sound with high-sensitivity speakers. Be aware that your max undistorted volume will be less than without the mod (general rule of this universe says you can't get anything for nothing!) and that running into distortion is not good for your speakers.
You can use this 'center-level' mod with DrLex's tone stack if you prefer.
In that case, retain DrLex's values and only change the TA2020's opamp input resistors:
8k2 pair for 47k (instead of 27k)
22k pair for 120k (instead of 68k)
Reason; the 10k center resistor demands that these values also be higher.
Superbass mod: If the bass range is still insufficient, for each channel handwire a 10n capacitor and 150k resistor in parallel, and then place this assembly in series with one end of the 20k/22k feedback resistor of the 5532 preamp.
Not one for the purists but makes for a much rounder sound with high-sensitivity speakers. Be aware that your max undistorted volume will be less than without the mod (general rule of this universe says you can't get anything for nothing!) and that running into distortion is not good for your speakers.
Anteaus - I've found that my Lepai 2020+ sounds pretty reasonable with the ton controls engaged (mostly to boost the trebel), but quite "tin canny" with them disabled. The problem, of course, is that with the controls engaged, I can't turn the volume up past halfway without distortion.
Which, if any, of the mentioned mods will allow the tone controls to be used while getting more volume out of the thing? Is there something specific to the tone controls that cause this problem, or is it just a general amp mod that's needed?
Which, if any, of the mentioned mods will allow the tone controls to be used while getting more volume out of the thing? Is there something specific to the tone controls that cause this problem, or is it just a general amp mod that's needed?
I'm particular interested in this mod, but I'm having the original 4558 opamp (SMD) with LP-2020A+ (with tone defeat) ,
photo will be nice
http://i.imgur.com/UEyp7.jpg
If you need to zoom into the opamp section, I can upload it later.
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No need, really, to thank the person who took this photo and first uploaded it... (And, yes, that would be me)
As I mentioned I don't have an SMD sample so I can't comment on actual component locations. The preamp in this model is somewhat different. If you know of a schematic I could suggest a mod.
@meeotch: It depends how they are disabling the tone stack. If the switch just bypasses a passive tone stack, then it would result in way too much overall gain. Which sounds like what is happening.
op amps have arrived from the digikey but can't figure out the orientation of how the chip should be soldered. Ones on the Lepai has a tiny dot on the L front (that is toward the faceplate when looking at the board from the front with top open as the picture above) of the op amp, but the once from digikey does not have one. I see it has a tiny slant on the edge of the chip but not sure...
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Some chips have a printed dot, some have a molded dot, some have a cut corner, some have a "U" shape on one end... do you have a pic/link of your IC? It sounds like yours has a slanted edge so with that slant on the left side pin 1 will be at the top left. Pin 1 on the PCB is the bottom left for each op amp, as viewed in the picture above (where that dot is on the 4558).
You're correct to want to get it right the first time. Ask if you still aren't sure. With this SMT stuff it's a PITA to have to redo. But it isn't outrageously difficult overall. I actually saved the two 4558s off my board, using a standard 30W soldering iron with a 2mm screwdriver tip.
You're correct to want to get it right the first time. Ask if you still aren't sure. With this SMT stuff it's a PITA to have to redo. But it isn't outrageously difficult overall. I actually saved the two 4558s off my board, using a standard 30W soldering iron with a 2mm screwdriver tip.
I bought the chips per your suggestion here: Digi-Key - NE5532AD-ND (Manufacturer - NE5532AD)
I understand so the dot corner goes on the top-left with the slant on the L side?
these things are tiny and my eye sight is getting old...
So... I've used my lil' thingy in a portable stereo and it works good and all - the only thing is that it CUTS the sound when the bass/volume (mostly bass, like when I turn on hiphop) get's too high - I'm using it with a pair of carspeakers (95dB SBL).
Is there any simple fix for this, hehe?
No real biggy, I just have to make sure the sound stays a little lower, however I want to max it out
Is there any simple fix for this, hehe?
No real biggy, I just have to make sure the sound stays a little lower, however I want to max it out
You can get a better power supply. Something like 13.5V/4A to replace the included 12V/2A. And/or you can try to keep the chip cooler. Honestly, though, I can't imagine why anyone would want to listen to a max'd out Lepai... It's just a "small, economical, get-around-town" amp, not a "take to the track and rev it up" amp.
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