# Starting off with Micca MB42X, now amp + sub?



## CTSNicholas (Sep 7, 2012)

Hey all you lovely audiophiles. A couple years back I was prepping for a poor man audio startup and purchased the Lepai LP-2020A+ .... then a year ago I was trying to find some good sounding shelf speakers to use while I built my house and worked inside ... something I could later use for TV or in the office on a computer so I purchased a set of the Micca MB42X...I snagged my 2020 and hooked up my sansa clip to it. It sounded very nice (to me) in terms of clarity... there was definitely a lack of bass with no sub and I couldn't crank my 2020 very high up because it comes with a cheap power supply. I read about a little hack job that involves using a monitor 5A power supply to drive the 2020 amp to get more 'good' out of it, so I am about to purchase one. I realize I am just messing around with the amp at this point. I am wanting to pair my Miccas up with a nice subwoofer and a competent amplifier. Am I supposed to be looking at a 5.1 Receiver to do the driving...or is there a higher end amp similar to the Lepai 2020 that has better power, and the ability to use a subwoofer? :dontknow: Money is an object but I won't name a price. I figured since I paid $90 for the speaker, I am probably looking another couple hundred to get an amp and sub. Thanks for your suggestions.


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## theJman (Mar 3, 2012)

Without providing a budget there's really very little anyone can do to assist. What you're asking is akin to telling someone you're looking to buy a car, but then you don't give them an indication of what you can afford. Finances always factor in as part of the decision I'm afraid, so without any guidelines it will be nigh impossible for somebody to help.


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## CTSNicholas (Sep 7, 2012)

Like I said, I am probably looking to spend up to another $200


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## theJman (Mar 3, 2012)

No, you said "another couple hundred". Depending upon how you define that it could just as easy be $400.


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## lovinthehd (Mar 17, 2012)

The cheaper integrated amps (the Lepai is a simple integrated amp) won't likely have bass management for a sub, an avr (audio video receiver) is a better choice (even if you don't need all the features). I'd suggest you look at the sub-$200 prices on such units at accessories4less.com. $200 may get you a cheap avr or sub, but both for $200 may mean going used. You may want to try just adding a sub like one of the entry level ones from Dayton at parts-express.com....

I've got one of those Lepai units, haven't heard about using a different power supply for more power, doesn't sound like a good idea somehow ....got a link to what you're talking about in this regard?


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## DqMcClain (Sep 16, 2015)

I've used the Lepai 2020's both with the factory power supply and with PSUs that will deliver more current. The rationale is that the larger current availability will cause a smaller voltage drop when the amp is used at higher output. To a point, this works... but don't expect a $30 amp to perform like a $100 amp simply because you paid an extra $20 for a power supply. A word of caution though: don't overshoot the max voltage spec. I've got a Lepai that is a brick with lights and knobs because of a voltage mismatch. 

As for bass management... adding a small powered sub would be the absolute cheapest solution. You'd basically tap the inputs to the Lepai and feed RCAs to the subwoofer, either L/R or just L depending on the sub. This approach works fine, but unless you have a volume control before the Lepai, you won't have the ability to vary the volume of the system as a whole. You'd only be able to control volumes independently... sometimes this is good, other times it's inconvenient.


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## CTSNicholas (Sep 7, 2012)

theJman said:


> No, you said "another couple hundred". Depending upon how you define that it could just as easy be $400.


Sorry, around here couple hundred means two hundred  Must be a regional thing! :R



lovinthehd said:


> The cheaper integrated amps (the Lepai is a simple integrated amp) won't likely have bass management for a sub, an avr (audio video receiver) is a better choice (even if you don't need all the features). I'd suggest you look at the sub-$200 prices on such units at accessories4less.com. $200 may get you a cheap avr or sub, but both for $200 may mean going used. You may want to try just adding a sub like one of the entry level ones from Dayton at parts-express.com....
> 
> I've got one of those Lepai units, haven't heard about using a different power supply for more power, doesn't sound like a good idea somehow ....got a link to what you're talking about in this regard?


I'd be interested in a good quality AVR and be willing to spend more than $200 on the set knowing I was buying up into a better unit. What would a 2.1 setup look like in terms of cost if I use my Micca's still and just purchase a quality amp and sub? I'd expect the amp to power bigger speakers than the Micca's if I were to ever upgrade down the road.

The power supply I am about to buy is this one from amazon.... http://www.amazon.com/gp/product/B003Z6ZR5O/ref=crt_ewc_img_dp_4?ie=UTF8&psc=1&smid=AS8PCMKEL4RLT This is what apparently a handful of the folks have used as I read the reviews and discovered they were using it 'fine' with the 2020.



DqMcClain said:


> I've used the Lepai 2020's both with the factory power supply and with PSUs that will deliver more current. The rationale is that the larger current availability will cause a smaller voltage drop when the amp is used at higher output. To a point, this works... but don't expect a $30 amp to perform like a $100 amp simply because you paid an extra $20 for a power supply. A word of caution though: don't overshoot the max voltage spec. I've got a Lepai that is a brick with lights and knobs because of a voltage mismatch.
> 
> As for bass management... adding a small powered sub would be the absolute cheapest solution. You'd basically tap the inputs to the Lepai and feed RCAs to the subwoofer, either L/R or just L depending on the sub. This approach works fine, but unless you have a volume control before the Lepai, you won't have the ability to vary the volume of the system as a whole. You'd only be able to control volumes independently... sometimes this is good, other times it's inconvenient.


I realize the amp is cheap :whistling: I was just curious what approach is best...and what I should expect. I am pleased with the audio quality of my setup...just the lack of bass gets me...which I suppose is pretty significant because who doesn't want bass? :wink2: I'm not familiar with powered amps yet. Sounds like they use AC to power the sub and then just snag the audio signal from the amp...or the source? I'd wonder how well it picks up the bass frequency doing that without an amp designed for it.


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## DqMcClain (Sep 16, 2015)

That power supply has 2/3 more current available than the factory-supplied PSU for the Lepai 2020's... so when your signal demands more current from the amp, it will be there for the taking. So, you'll notice a little more meat on the bottom end even if that's all you do. 

Using a powered sub, basically all you have to do is feed it a full range signal. Anything worth owning will have a crossover built-in, maybe even a variable one depending on what you buy. You can set that to wherever the Micca's start to roll off naturally, and the sub will only respond below your crossover point. I've got a Dayton SUB-800 ($99) in a 2.1 setup in a very small office, and it does nice work. I also have a Yamaha YST-SW012 (also $99) in a similar setup in a different and slightly larger office. By similar, I mean they are both mated to Mackie CR3's, and tapped using RCA splitters. Both subs perform acceptably under these circumstances, but if I had to buy either one of them again, I'd get the Dayton. Same price, and the Dayton has a variable crossover. The Yamaha boasts a lower F3 (28Hz vs the Dayton's 40Hz), but I still consider the variable crossover to be worth it. Both are 8" drivers, so they're meant for lighter reinforcement of bottom-end material, but both companies offer larger and more robust designs (for more money). 

If you want to go with an AVR that will give you much more functionality, a powered subwoofer can still be very easily integrated as most AVRs have an output specifically designed for just such a purpose. I'd say solve your immediate problem, and save your money to get a better AVR later. The Lepai/Micca assembly is serving your purpose now, and adding a sub to your current setup will give you what you're looking for with the smallest impact on your finances.


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## lovinthehd (Mar 17, 2012)

DqMcClain said:


> That power supply has 2/3 more current available than the factory-supplied PSU for the Lepai 2020's... so when your signal demands more current from the amp, it will be there for the taking. So, you'll notice a little more meat on the bottom end even if that's all you do.
> 
> Using a powered sub, basically all you have to do is feed it a full range signal. Anything worth owning will have a crossover built-in, maybe even a variable one depending on what you buy. You can set that to wherever the Micca's start to roll off naturally, and the sub will only respond below your crossover point. I've got a Dayton SUB-800 ($99) in a 2.1 setup in a very small office, and it does nice work. I also have a Yamaha YST-SW012 (also $99) in a similar setup in a different and slightly larger office. By similar, I mean they are both mated to Mackie CR3's, and tapped using RCA splitters. Both subs perform acceptably under these circumstances, but if I had to buy either one of them again, I'd get the Dayton. Same price, and the Dayton has a variable crossover. The Yamaha boasts a lower F3 (28Hz vs the Dayton's 40Hz), but I still consider the variable crossover to be worth it. Both are 8" drivers, so they're meant for lighter reinforcement of bottom-end material, but both companies offer larger and more robust designs (for more money).
> 
> If you want to go with an AVR that will give you much more functionality, a powered subwoofer can still be very easily integrated as most AVRs have an output specifically designed for just such a purpose. I'd say solve your immediate problem, and save your money to get a better AVR later. The Lepai/Micca assembly is serving your purpose now, and adding a sub to your current setup will give you what you're looking for with the smallest impact on your finances.


FWIW many subs do not have crossovers but rather only low pass filters. Your Sub-800 doesn't appear to have but a low pass filter per its manual, and I don't even see an adjustable low pass filter on the Yamaha nor any info about either a low pass or high pass filter in its manual.


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## lovinthehd (Mar 17, 2012)

CTSNicholas said:


> Sorry, around here couple hundred means two hundred  Must be a regional thing! :R
> 
> 
> 
> ...


FWIW I always understood couple to mean 2 but looking up a definition I see there is some variance there....

Interesting about the power supply "upgrade" altho I just bought the Lepai for fun in comparing to a much more capable amp, don't really use it. 

If you want more bass I'd suggest the subwoofer route, but prefer bass management so I can control the frequencies sent to the sub vs speakers. You can get by just "blending" the capabilities of the sub via its own low pass filter, but many don't have a high pass filter to avoid duplicating frequencies sent to the speakers, thus limiting the benefits. An avr can be had for as little as $200 but you will gain more features/connectivity/capabilities as you go up the ladder....I use my setups for both music and movies so prefer the avr route. If music only I've used my 2ch preamps without bass management, just not my preference now that I've added video to my setups in each room. YMMV.


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## DqMcClain (Sep 16, 2015)

lovinthehd said:


> FWIW many subs do not have crossovers but rather only low pass filters. Your Sub-800 doesn't appear to have but a low pass filter per its manual, and I don't even see an adjustable low pass filter on the Yamaha nor any info about either a low pass or high pass filter in its manual.


Yeah, you're right. It's not a crossover, since it isn't routing the upper portion of the signal anywhere. But the Dayton does have a frequency adjustment on it. The images available on PE website show it on the amp panel. And you're right, no such adjustment exists on the Yamaha... which is why I'd pick the Dayton. I'd have a hard time believing that the Yamaha is feeding full-range signal to its driver though... there must be a LP filter. It's not hard to imagine that they just picked a frequency that would be favorable for that unit's specs and and designed a fixed LP into the amp.


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## lovinthehd (Mar 17, 2012)

DqMcClain said:


> Yeah, you're right. It's not a crossover, since it isn't routing the upper portion of the signal anywhere. But the Dayton does have a frequency adjustment on it. The images available on PE website show it on the amp panel. And you're right, no such adjustment exists on the Yamaha... which is why I'd pick the Dayton. I'd have a hard time believing that the Yamaha is feeding full-range signal to its driver though... there must be a LP filter. It's not hard to imagine that they just picked a frequency that would be favorable for that unit's specs and and designed a fixed LP into the amp.


Just pointing out the limits of "crossover" on subs. Better subs at best usually only have a particular crossover point of 80hz let alone being adjustable. Just can't stand the low pass filter, despite labeling by the cheap-butt sub companies, being called a "crossover"


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## DqMcClain (Sep 16, 2015)

lovinthehd said:


> Just pointing out the limits of "crossover" on subs. Better subs at best usually only have a particular crossover point of 80hz let alone being adjustable. Just can't stand the low pass filter, despite labeling by the cheap-butt sub companies, being called a "crossover"


Indeed. To be fair in this case, the mistake is mine. Dayton does not refer to their adjustable low-pass filter circuit as a crossover. They specifically say "... a phase switch, independent volume control, an auto on/off switch (activated by an input signal) and a_ variable 12 dB electronic low pass filter_". I quoted enough of that description to cover another vastly more common mislabeling though: "phase"

WAY TOO MANY subwoofer manufacturers, good quality ones included, use the term "phase" when they mean "polarity". The polarity of a signal is +/- voltage with respect to ground, and manifests as the direction of cone travel for a given input. The phase of a signal is referenced to _time_, and is frequency dependent. 

We tend to think of a signal displaced by 180deg as being the opposite, but in fact it is delayed by a half-cycle at a particular frequency. That's why "phase response" is such a tricky issue, and why you see massive cancellation at harmonically related frequencies when you look at a "phase response" curve. 

A signal played back against it's polar-inverse counterpart will cancel completely, as the sum of the signals is zero because one side is asking for a series of voltages, and the other side is asking for the equal and opposite voltages. 

So in reality, that "Phase 0/180" switch should be labeled "polarity".

/end rant.


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