re: mini amp

coloradobob

coloradobob

New member
Anyone tried incorporating a Lepai Mini Amp into their build?

Here are the specs that I pulled off ebay:









MP3, iPod, CD player input jack
200W max power output
Super bass on/off switch
Low distortion
Great for use on your vehicle or your home
Smart, lightweight aluminium casing
Pre-drill holes in bass for easy attachment

The amplifier is lightweight, has a matt silver casing and allows for full control of your volume, treble and bass output. It also has a jack for plugging your MP3, MP4, iPod or CD player into

Specifications:



Output: 200W [100W + 100W]
Jack input: 1/8" [standard stereo jack]
Voltage: 12V
Material: lightweight aluminum
Dimensions: 14 x 7 x 4cm [5.5 x 3 x 1.5"]
Brand new and boxed

Still learning, hence the question.
I'm just throwung this example up there to use as a comprehensive learning tool for myself and possibly others. I'm interested in the whyfor's and the whereas's........., the why of whether you would or wouldn't use this particular example. A kind of Amplifier 101.
 
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I thought it was as well which is why I chose it(at random)as an example. Figured if I knew why this would be the wrong choice I would better understand what would be the right one and why. The why is what I hope to learn.
 
I dont know much about this either but I know most horn speakers the size you would want to build a call out of are rated for around 20 watts. If you wanted to use a cone speaker, such as a pioneer car speaker I think they could handle 100 watts.
 
Hi Okie, I plan on using a Speco SPC5C to start out, it seems to work well for most folks. Later who knows? Just trying to learn the whys and why nots in an attempt to understand all this better. Knowledge is the key to doing anything well. I'm completely out of my element when it comes to electronics. I knew the 100w speaker was over the top, I'm trying to learn why........, in laymans terms of course. I'm hoping someone will take a shot at it in language we can all understand. "Speaker Basics 101" would make a great thread for those of us NOT in the know. Anyone out there game?
 
Thanks Mike.
I appreciate the source that you provided for the amp. I've seen them mentioned often. Still taking in all the pros and cons of amps. so I'm still undecided.
So far I've got a Nady and an RCA M4304 4gb digital media player. I just bought a Speco SPC-5P on eBay and I'm watching for a decent deal on a 9.6 volt R/C battery & charger preferrably name brand.
So, I'm almost there. Some more looking, listening, and learning to do before I end up with a finished caller. It shouldn't take too long though, I've gotten some good coaching along the way from a couple of the other members, I just have a few decisions to make and I'm there.
I'm pretty much set on the design of one of the other guys. Doggin Coyotes was generous enough to let me eyeball one of his builds and it's a really nice compact professional looking caller. Impressive. Just whats needed to get the job done. Then I get to experiment with a few ideas of my own.
 
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Finally decided to just go ahead and use an RS amp.
Absolutely NO white noise and plenty loud. It may just be the combination of components that I'm using but I find nothing wrong with the RS amp. Good sounds, an RCA M4304 Digital Media Player a Speco Sp5 Speaker make a pretty impressive homebuild. It's louder than loud and absolutely distortion free, no complaint here.
Not wishing to offend anyone but either I've done something very right (I had plenty of help from my friend Larry aka Doggin Coyotes) or those dissing the RS have done something very wrong.
The only drawback I can see is one of availability. The fact that they are continuously out of stock is my only complaint.
I know someone that may have a couple 4 sale if anyone is having trouble finding one. Send me a PM if interested and I will provide the source.
 
Hey Coloradobob--Can you post pics of your build, I waiting on my nady and looking at pics trying to figure how to finish my build--Also I have the RS speaker is the Speco Sp5 a better speaker or am I ok with this one?? I got lots more questions but I want take up no more time...

Thanks,
David
 
When I was still using my Nady 151 I used it quite a bit without an amplifier. If you are using a horn speaker mine was loud enough for most places that I called.

One thing to consider is that the Nady specification for dynamic range is 20,000 Hz on the upper end whereas the little Radio Shack amp is something like 13,000 (can't remember for sure but it seems like it is less than the Nady). If you use the mini amp you are reducing your sound quality to that of the amp.
 
Originally Posted By: JackindistressWhen I was still using my Nady 151 I used it quite a bit without an amplifier. If you are using a horn speaker mine was loud enough for most places that I called.

One thing to consider is that the Nady specification for dynamic range is 20,000 Hz on the upper end whereas the little Radio Shack amp is something like 13,000 (can't remember for sure but it seems like it is less than the Nady). If you use the mini amp you are reducing your sound quality to that of the amp.

Mr. Jackindistess left you fellas a few nuggets right there. NO, not those kinda *nuggets*!

Good advice, helpful tips, useful information kinda nuggets, ya know.
 
I had a whole writeup for you yesterday, then the power went off and wiped it out before I posted.
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Forget the 200W amp idea, you would need about +/- 35V D.C. supplies to get that kind of power. Not only isn't that practical (6 12V batteries in a series/parallel pack), it's dangerous as heck.
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Here's a couple of amps that will run a Speco SP-5 loud enough to call with just fine (an 8W is louder than a PM-4 amp, because I tested them side-by-side through the same speaker).

7W assembled amp - $19.95CANUK153

20W bridged amp - $19.95 CANUK193


Those will both run on a single 12V battery, and something like a 5 Ah runs them all day (plus my decoy). Now you have something you can carry around without a wheelbarrow.
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Quote:Frequency response: 30Hz to 20KHz (-3dB)


Matches the Nady high-freq. so you're good to go.
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I'd go with the 20W, but keep the amp volume off max. (20W will distort, anyway), just because it has those beefy heatsinks and should run fine in hot weather without getting toasty. I'm a little concerned the other one might be under cooled at high volume on a hot day (guessing). Plus, they cost the same, so it's kind of a no-brainer.
You're getting some good tips here, keep the thread going if you have any more questions. You can build a pretty nice caller on the cheap that works just fine.


If you're good at soldering, here are a couple more options:

18W Audio Power Amplifier Kit

8W mono amp kit
That last one is the one I used, because I like the screw terminal connections. A big heatsink comes with it, but it's not shown in the pic.
 
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Bowknut I'd be happy to send you some pictures of my build but all you would see at this point is a picture of the Speco, the amp. and the MP3 spread out and hooked up on the kitchen table. Your basic VarmentAl e-caller only with an MP3 Player instead of a CD Player. The Nady hasn't even been taken out of the box yet other than to just take a quick look at it.

The performance that I'm getting right now is from that basic caller minus the Nady. I don't even pretend to suggest that I know much beyond that so I'm not really the person to seek advice from on this, but several of the members that have responded here are. One of them is my mentor, DC. If he says or even agrees that the amp. will effect the sound quality when used in combination with the Nady then I'd believe him. I'm fortunate enough to have had Larry take me under his wing and show me the ropes. Larry hasn't steered me wrong yet even though like a kid I have to bang my thumb with a hammer several times to realize that I just should have listened and done what he said to do the first time around. Patient man!

Will I try the Nady w/amp.? Sure, why not since I have the amp anyway. Doesn't mean that's the way it's going to stay. Bottom line.........., Whatever works.

I started with the basic caller figuring that if nothing else I would at least end up with that......, a good basic caller.
The Nady was the very first item that I purchased since I intended to go wireless eventually anyway and I thought the price to be a fair one. The fact that the Nady and the amp were both 9-volt also appealed to me. The information that I was provided with after buying the amp made it an exceptional buy. And I've gained a new friend in the process.

David, you would do well to follow the advice of those that have responded here. These guys have been there and done that.

As for my build this is what I can tell you for now. I'm very happy with my choice of components so far.

I like the Speco, it came highly recommended and didn't disappoint.

I'm pleased with th RS amp. so far as well. It's small, seems to be dependable and again it, like the Nady, is 9 volt. If you consider that I also have an amplified listening device powered by a 9 volt battery that I would like to incorporate into my build keeping everything 9 volt just seems simpler........., for now! Like most I will take what I learn from others and try to build a better mousetrap. It's the nature of the beast.

As far as the MP3 media player goes I chose the RCA for the sound quality and it's features over some of the cheaper MP3's. $53 versus $20

I added a few nice clean sounds I had on file.

That's where I'm at at the present time and I'm very pleased so far.

Listen to these guys, they know their $hit, i'm still learnin.'

Have a great day!

John
 
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John,

Hey, if you're needing 9V inside the case (for the Nady and amp both), you might look into using a couple of these and running off a 12V battery. 9V cells get expensive quick.

9V regulator IC

3-pin, solder it across a 12V battery and 9V comes out the other pin. $.99 and you paid for it with one battery.
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I'm thinking 9-volt r/c battery for starters. Maybe on the next caller. Did I say that?

That's a nice little piece of information. One that may show itself at some point in the future.

My main gripe about 12v systems as in the case of my 512 is that they are heavy. That said they are also reliable and certainly have a place in a caller. For now I'm going light, on the next one?

Hope my wife isn't looking over my shoulder. Funny, my wife doesn't really know one gun from another but she sure knows a new one when she sees it. I've got a feeling callers won't be much different. lol

Thanks for the input.

have a great day,
John
 
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Yeah, the reason I use 12V for the callers is that I can get amps that run on 12V and give me 8+W of power cheap. If you step down from that, it gets hard to find a "cheap" amp, because you need to go to a bridged configuration.
But you're right, they get heavier.

Sounds to me like you've got a good handle on the design tradeoffs, not much more I can offer.

Good hunting.
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David, with guys like Doggin Coyotes, Evil Lurker, Jackindistress and others answering our questions I'd say we're in very good company and in pretty good shape building our callers.

As fas as questions go, don't worry I've got plenty.
Hey did you checkout those videos on YouTube that I was telling you about?

Pretty slick huh?
 
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coloradobob... If you get the urge to try a Velleman amp in your next build I might have a built AMP or kit I could donate to the cause as I am sorting through all the spare caller pieces parts I have aquired over the past too many callers built...
 
That's mighty nice of you lowtemp, I may just take you up on that.

Is this how the addiction to call building starts? You build your first caller then piece by piece you start to acquire more and more parts.

Eventually you look at all these part and figure, "If I only had a FEW more parts I could build another caller." And lets not forget the improvements, so now there's even more parts. Next you start cannibalizing earlier builds to add or swap out with other parts only to find that you need more new parts so you can use those old parts.

Before long even the parts will have parts and there will be so many xtra parts that it will be time for another build just to use up all those parts which means now you need a few more new parts............., and improvements!

I think I see a pattern here. I'm guessing this is how it goes down more or less from here on in. Is there a cure?

LT, I'm even afaid to ask how many is too many for fear of seeing what I could be in for.

Lord I think I'm in trouble!

You have yourself a great evening!
John
 
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