Do you have a spare LED, resistor of about 500-1kΩ, and a diode? If so, you could make a simple polarity checker.
If I remember right, the white stripe indicates the positive lead, but that is somewhat of a guess. Too much of a guess, actually. You don't want to connect the supply with the wrong polarity.
If I remember right, the white stripe indicates the positive lead, but that is somewhat of a guess. Too much of a guess, actually. You don't want to connect the supply with the wrong polarity.
Hi, thanks for the reply.
I gave a longer reply which got "lost" so here is the gist of it:I'm not a dabbler. I ordered the amp from China. Cost about £10. Iexpected to have to buy a lead / adapter but they kindly sent me alead with the plug missing. I have several old car cigarette lighter leads (whatever the short name is - CCLL) and a CampingGaz Euro transformer which provides 12v at 5amp and takes a CCLL. I didn't want to spend much extra. I've just had the thought that if my old CCLLs have black and black and white wires there's an excellent chance that all I need to do is cut the end off and fasten like to like. I probably should buy or borrow a Voltmeter but it is probably worth taking the risk and buying a new amp if necessary. Assuming, of coursef *that at least one plug has these wires.I was hoping that someone with this amp would know. My web search suggested black and white is usually positive. I guess if it isn't I'll find out pretty quickly and only risk harming the amp.
Thanks again.
I gave a longer reply which got "lost" so here is the gist of it:I'm not a dabbler. I ordered the amp from China. Cost about £10. Iexpected to have to buy a lead / adapter but they kindly sent me alead with the plug missing. I have several old car cigarette lighter leads (whatever the short name is - CCLL) and a CampingGaz Euro transformer which provides 12v at 5amp and takes a CCLL. I didn't want to spend much extra. I've just had the thought that if my old CCLLs have black and black and white wires there's an excellent chance that all I need to do is cut the end off and fasten like to like. I probably should buy or borrow a Voltmeter but it is probably worth taking the risk and buying a new amp if necessary. Assuming, of coursef *that at least one plug has these wires.I was hoping that someone with this amp would know. My web search suggested black and white is usually positive. I guess if it isn't I'll find out pretty quickly and only risk harming the amp.
Thanks again.
Lepai 2020A+ DC offset survey
Ladies and gents, I would be grateful if you could contribute your findings to my Lepai 2020 DC offset survey.
Thanks
Ladies and gents, I would be grateful if you could contribute your findings to my Lepai 2020 DC offset survey.
Thanks
Loop-through on the Lepai's line-in?
Quick question;
If one is using either of the inputs (mini-jack or RCA's), can the other connector be used to send the input on to another device?
ETA >> as with, for example., the Audioengine A2 desktop monitors. I ask because this is with a view to using an active sub.
Quick question;
If one is using either of the inputs (mini-jack or RCA's), can the other connector be used to send the input on to another device?
ETA >> as with, for example., the Audioengine A2 desktop monitors. I ask because this is with a view to using an active sub.
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Yes, with two caveats.
First, it seems that some models of this amp have the 3.5mm input L/R connections reversed (I'm going from memory, but it should be documented + pics somewhere in this thread). My fix was just swapping the speaker outputs, or you could do some minor surgery and correct the PCB with jumper wires. The RCAs are L/R correct.
Secondly, the input jacks are simply paralleled, so it does affect the in/out impedances. It's likely this wouldn't be an issue in most cases.
First, it seems that some models of this amp have the 3.5mm input L/R connections reversed (I'm going from memory, but it should be documented + pics somewhere in this thread). My fix was just swapping the speaker outputs, or you could do some minor surgery and correct the PCB with jumper wires. The RCAs are L/R correct.
Secondly, the input jacks are simply paralleled, so it does affect the in/out impedances. It's likely this wouldn't be an issue in most cases.
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Thank you!
The channel-reversal on the mini-jack won't be a problem, I'll use that as the the output to the sub.
The line-in will be from my M-audio Delta 410 soundcard, hopefully the paralleled impedences of the Lepai and sub won't cause problems (the sub is a Pioneer, and the specs say 50Kohm in).
Overall, good news - I've ordered a Lepai (two, actually!).
switching on and off ...
Is there a 'best practice' for switching on and off?
I get the impression that Lepai's are fragile, and powering up might be one of the moments in the operating cycle when they're likely to break.
I tend to simply switch most audio equipment off at the wall, rather than using the power switch or button on the device itself, would this be advisable?
Is there a 'best practice' for switching on and off?
I get the impression that Lepai's are fragile, and powering up might be one of the moments in the operating cycle when they're likely to break.
I tend to simply switch most audio equipment off at the wall, rather than using the power switch or button on the device itself, would this be advisable?
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Thanks again.
Does the linear supply improve things (over a decent size switcher)? A 4-5A linear would be quite expensive in comparison, I'm guessing.
Paralleled pairs of Lepais?
And yet another question;
I know that a single Lepai, and most other amps like it, can't be bridged to mono, but can pairs of them be 'paralleled' into a single stereo load?
I'm going to guess no, unless maybe they're a selected/matched pair (varying DC offset?).
is there otherwise a way of modding them, or adding (reasonably simple) additional circuitry that would allow it?
And yet another question;
I know that a single Lepai, and most other amps like it, can't be bridged to mono, but can pairs of them be 'paralleled' into a single stereo load?
I'm going to guess no, unless maybe they're a selected/matched pair (varying DC offset?).
is there otherwise a way of modding them, or adding (reasonably simple) additional circuitry that would allow it?
I use a 24v linear to supply my Creek headphone amp, and I notice that when I cut the power to the PSU the supplied DC drops off quite slowly (takes several secs for Creek's LED to go out), unlike the original switching PSU, and it SEEMS like it would be easier on the equipment.
(One thing I NEVER do is plug a live DC jack into kit that's switched on)
As I said, I've tended to power everything off this way out of habit, but I don't actually know if this always good, bad or indifferent practice - perhaps good for some equipment and bad for others?
I have no real data to showing one being an improvement over the other, outside of that obvious purchased-new pricing.
I wouldn't recommend it.
The reservoir capacitors are slowly discharging through the LED.
This relates to a common topic of discussion with computers and electronic equipment - turn it off or leave it on. For the Lepai with a decent supply I doubt it makes much difference.
Lepai volume cut-off on RIGHT channel
Hi guys,
I am experiencing this strange phenomenon with one of my Lepais (I have 3). The RIGHT channel does not go louder whenever I crank the volume beyond 1 o'clock, however the LEFT channel goes loud fine. By the way, I usually don't play this loud.
I took out a DMM, switched to VAC, ran a continuous test tone and took voltage measurements from the speaker terminals. This is what I found. The RIGHT signal stops at 1 o'clock position of the volume, whereas the LEFT signal goes all the way. I tested the volume pot and input signal but found nothing wrong. Where could the problem be?
Hi guys,
I am experiencing this strange phenomenon with one of my Lepais (I have 3). The RIGHT channel does not go louder whenever I crank the volume beyond 1 o'clock, however the LEFT channel goes loud fine. By the way, I usually don't play this loud.
I took out a DMM, switched to VAC, ran a continuous test tone and took voltage measurements from the speaker terminals. This is what I found. The RIGHT signal stops at 1 o'clock position of the volume, whereas the LEFT signal goes all the way. I tested the volume pot and input signal but found nothing wrong. Where could the problem be?
Hey guys,
I've had one of these for about 1.5 years now and have run it maybe 30 hours off of a 15.7-16.0 volt NiMH battery pack (leftover parts from a hybrid car) cranking it up. I keep reading online it should be shutting off at 14.4 volts though... I just ordered 3 more of these for different projects, should I be expecting a few to blow up (or all of them?) if I run 16+ volts? I think my last pack was at 16.3 volts and I ran this amp for an hour without problems. I don't want to have it blow up on me in the middle of a 30 mile bike ride -- should I be using a regulator?
I've had one of these for about 1.5 years now and have run it maybe 30 hours off of a 15.7-16.0 volt NiMH battery pack (leftover parts from a hybrid car) cranking it up. I keep reading online it should be shutting off at 14.4 volts though... I just ordered 3 more of these for different projects, should I be expecting a few to blow up (or all of them?) if I run 16+ volts? I think my last pack was at 16.3 volts and I ran this amp for an hour without problems. I don't want to have it blow up on me in the middle of a 30 mile bike ride -- should I be using a regulator?
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I had similar problem, it was the tone control switch (a really cheap switch), what happens when you press and release it?
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