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I got the micca mb42 and lepai 2020+ amp need help

post #1 of 10
Thread Starter 

Once i higher the volume to high then my amp shuts off it is really starting to annoy me since i like blastic rock songs and it really wont work

 

Is it my speaker or amp?

is it the amps power control?

will a new amp or speaker fix the problem?

post #2 of 10
Thread Starter 

Is no one an expert on this stuff? 

:P

post #3 of 10

It depends on the size of room etc, etc The Lepai is more a 'near field' or pc amp which probably outputs about 10w (true power not RMS) maybe better suited to more sensitive speakers or with an active sub (with stereo pass throughs for the speakers) to handle the bass if you want high volume.

 

See- http://www.head-fi.org/t/663535/lepai-2020a-amp-shutting-off

 

I use a Pioneer A-307R seperates stereo amp (80w x 2iirc) with some ugly old classic Pioneer CS363 full range, 3 way speakers, costing a grand total of about £35 for both (2nd hand). It's a beast set up, as a bonus It also has a clean, powerful headphone amp section. If you have the desk space (My monitor sits on top of the amp) and don't mind old ugly speakers this is the way to go with regards to power and SQ for a PC.


Edited by Ari33 - 11/24/13 at 2:15am
post #4 of 10
Thread Starter 

Ari33

the Pioneer A-307R costs about 200 dollars i can not afford that, 

and no one seems to have the  Pioneer CS363

 

I like the sound quality of my speakers its just the amp that keeps shutting off, waht do i dp ._.

post #5 of 10
Quote:
Originally Posted by IatomI View Post
 

Ari33

the Pioneer A-307R costs about 200 dollars i can not afford that, 

and no one seems to have the  Pioneer CS363

 

I like the sound quality of my speakers its just the amp that keeps shutting off, waht do i dp ._.

 

Yes, perhaps new but maybe 80 dollars 2nd hand?. Pioneer CS363 are really old classic speakers, ugly.. but still sound great.

 

If replacing the amp for a more powerful one is out of budget...  someone on another thread did suggest using a power supply that could provide 5 amps (instead of the supplied 2A unit) does help with the Lepai... not sure by how much but it might be worth trying. They also replace one of the capacitors which is supposed to help the bass. I'll try and find the thread for you.


Edited by Ari33 - 11/24/13 at 1:41pm
post #6 of 10
post #7 of 10
Thread Starter 

So if i where to buy the amp u suggested second hand, i would be able to turn up the voulme?

post #8 of 10
Quote:
Originally Posted by IatomI View Post
 

So if i where to buy the amp u suggested second hand, i would be able to turn up the voulme?

 

It has around 4 times the power.. so yes higher volumes would be achieved. Instead of the amp 'clipping' and turning itself off to prevent damage the limiting factor would become the sensitivity of your speakers and their power handling capability - rated to around 75 watts iirc?

 

From the MB42 operating instructions..

 

The MB42 can be used with amplifiers between 15 to 100 watts per channel as long as reasonable care is exercised. If there is audible distortion, turn down the volume until the distortion goes away. Never allow the speaker and amplifier to play for more than a few seconds when there is audible distortion. 

 

 

So the Lepai is definately right at the minimum end of the speakers power handling scale.

 

 

If the numbers are correct, the MB42's sensitivity is rated at 85dB 1W/1M, so with your speakers at 1 metre listening distance, your lepai should provide enough power (Very generous estimate @ 15w per channel and if it wasn't clipping) to make the MB42's produce around 99.7dB?

 

With a 80W per channel amp, a safe 70W per channel input into your (75w rated) speakers at a 1 metre listening distance should produce around 106.46 dB.

 

At 3 metres listening distance these numbers change to aprox 90.26dB and 97.25dB respectively.

 

That might not sound like much of an increase but remember that each 10dB increase is perceived as aprox double the volume.

 


 

 

Try a beefier 5A power supply first, the 2A one simply does not supply enough amps for the amplifier to produce the claimed 20 watts.


Edited by Ari33 - 11/25/13 at 4:53am
post #9 of 10
Thread Starter 

Can you link me to a powersuply i can buy that is suitable for my situation?

post #10 of 10

I don't own the Lepai to measure the jack size for you but something like this would be fine if the (:Internal Diameter: 2.5mm , External Diameter: 5.5mm) jack size is correct.

 

http://www.amazon.com/Replacement-adapter-charger-Benq-Monitors/dp/B003Z6ZR5O/ref=sr_1_1?s=electronics&ie=UTF8&qid=1385556395&sr=1-1&keywords=12v+5a+power+supply+lepai

 

If you look at the 'Frequently Bought Together' section on the above listing you'll see the Lepai amp in there, also see the customer review comments below it too where people have bought it to pair with a Lepai, it seems it makes a big difference.

 

Remember and post back and let us know if it helps improve things for you.


Edited by Ari33 - 11/27/13 at 4:59am
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