Mini amps? Need help/suggestions/advice

[v3man]

(Note: I don't know much about CPU audio so please bear with me)

So I have a pair of bookshelf speakers (link here) hooked up to my computer and they are currently hooked up to a cd player/receiver (the thing with 3 blue rings on the right). There is a lot of noise coming from the speakers when the cd player is on. I am sure it is the cd players fault because when I hooked everything up to a higher end receiver, the noise was gone.

So I've decided to purchase hopefully a mini amp for this. I was looking into the Pyle PTA2 and PTA3 but am not sure about how well specs meet up etc.. because, as I said before, I don't know much about ohms, watts, specs and quality.

I need opinions, suggestions, or general advice on which direction to head and what to look for. I don't think i can fit a home theatre receiver on my desk (the mini amp would go where the current device is). My budget is somewhat tight so a good balance between price and quality is preferred. I won't be blasting my music hardcore loud or anything but I would enjoy good sound quality at a reasonable volume.

Or am I asking for too much?

Anyways, here's a pic:

 

[Odin75]

Ok, the only problem I see with those is that they have so little power. Your speakers would take up to around 100watts each max. I'm not saying blow them up, but that amp looks weak. Specially when you consider they are measuring at 4ohm, and your speakers take 8ohm. Ohm represents the resistance (impedance) a speaker has in receiving that power. Meaning that those 15watts and 40watts of the PTAs turn into a lower number once you hook your Insignias, because they will add resistance. You would still hear them, but probably not near the volume you enjoy.

I would look more into something like this: Mini Hi-Fi Stereo Amplifier ($14.99 + Shipping)
I'm not sure at what Impedance they measured, or if they are exaggerating the values, but that should give you more power. But be aware that's just a idea, I have not tried that item myself, nor done business with that vendor.
I'll would wait for someone with more knowledge in this area and give you a specific unit recommendation, but at least know you what to look for now.

Good luck.

 

[obobski]

how many dollars are you looking to spend?

if you want something small, built like a tank, high quality, etc, look at Firestone Audio's little desktop amp, if you're ok with a normal 17" component, grab some used receiver flying a decent brand's colors (h/k, Yamaha, Sony, Marantz, etc), or go with new toys from h/k or Pioneer (either of h/k's current stereo receivers, or Pioneer's A-35R)

as far as the "mini hi-fi stereo amplifier", dollar says thats PMPO wattage

one thing to note, 10-20W/ch is more than enough for this application, at 90 dB/W/M/8Ohm, 8W/ch/8Ohm input will probably be unbearably loud if fed continuously, but that doesn't mean you don't want that much power (or more) for headroom

and before you buy anything, gotta ask, on your (awesome looking) receiver, is it plugged into the same power strip/whatever as the rest of your gear (I'm thinking this could be as simple as a ground loop)

 

[v3man]

So the PTAs would underpower my speakers?

That Mini Hi Fi Stereo Amp is interesting but at that price I don't exactly know what to expect. Haha.

In terms of price, It really all depends on quality. If i really can't find good quality at less than $100, then I will go for higher (but would rather not). As for the ground strip, I changed it and the noise remains. So I guess it's not a ground loop?

90 dB/W/M/8Ohm

Sorry I couldn't follow you there First and last exposure I had to this type of talk was college physics and that was about 3-4 years ago. haha

Thanks for the help. Keep it comin

BTW: is there a thread I could read that walks me through all this computer audio stuff?

EDIT: I just looked at all the Firestone audio headphone amps off their website and noticed that they don't have speaker wire outputs. But they look awesome and would like to use one or something like it.

 

[obobski]

http://www.audiojunkies.com/product/819/firestone-big-joe-reviews <- firestone thing (their website hates opera, and i'm too lazy to open IE, but its on their website under Power Amp -> Big Joe, as well)

as far as the PTA and "underpower", I doubt it, but I also doubt they'd be any improvement, given that we're talking about Pyle

the mini hifi thing's output is probably measured in terms of PMPO watts, PMPO stands for Peak Momentary Power Output, in other words "how much power you can push for some nearly instantaneous point of time in lab conditions and then explosion" basically

as far as the 90 dB/W/M/8Ohm talk:

those speakers are listed by Insignia/BB as having an efficiency rating of 90 dB/W/M, which means at 1 meter distance, 1W of power into 8 ohms will give you an SPL of 90 dB assuming anehoic conditions and a few other variables which you'll never be able to recreate in your house, basically simplify that to:
if I put 1W into one of these, it'll give me 90 dB output

with two of them, you can estimate at 93 dB (even though, we aren't talking sine waves, we can be lazy, lol)

what this ultimately means FOR YOU:
2-4W/ch is more than enough to actually drive these for a desk setup, although I would suggest at least 20W/ch for headroom (i.e: peaks), which is overkill with modern material (WOOOOOOOO for running the levels at -1.3 dB 'round the house) but nonetheless a decent idea

a 100W amplifier would not be a bad idea, but it isn't required, and it'll never see 100% continuous output for normal usage

I'd still suggest to look at the Pioneer A-35R or some used equipment before I'd go for the firestone box, mostly because it'll save you quite a bit of cash, if you have a thrift store nearby, go check that out, I've found a number of decent components via this route (no you won't get HDMI and all that, but it'll drive your speakers and shouldn't hiss), just make sure you can return whatever device if its broken, and try another one, or at least just get your cash back

 

[v3man]

Ahh i see. I think i will try the thrift store route because I got the idea of putting my LCD monitor on top of a 17" component (unless it is not recommended).

Can you help me with what specs I should be looking for in the receiver? Should I be looking at components with 8 ohm resistance? And would anything under 100W output be preferable?

Thanks again obobski!

 

[obobski]

Ahh i see. I think i will try the thrift store route because I got the idea of putting my LCD monitor on top of a 17" component (unless it is not recommended).

Can you help me with what specs I should be looking for in the receiver? Should I be looking at components with 8 ohm resistance? And would anything under 100W output be preferable?

Thanks again obobski!

depends on the component if you can set something on top of it, most of them will have warnings about how you should leave something like a foot clearance on all sides, most of these are a bit conservative, get your receiver, and try it out, if it gets too warm for comfort on top, leave it open to the air, perhaps even add a fan, if it runs fairly cool, I don't see any issue with placing something on top of it, as long as it doesn't deform the case or make it heat up a lot

as far as specs, something that says it can handle 8 ohm speakers, yes, if this is inside of a range (for example"4-8ohms" or "4-16 ohms") that is fine as well, generally this requirement is satisfied by most components (8 ohm is fairly common)

as far as power output, I wouldn't worry too much, you could connect a 1000W/ch unit to these, and as long as you didn't turn it way up, you won't have any issues, although to give you a ballpark range, something in the 20-80w/ch range would be "good", anything more wouldn't be "bad", and anything less could be a problem

oh, one more thing, make sure whatever shop will allow you to return the device after you've purchased it, if it doesn't work, or work for you

 

[v3man]

Sweet! Much appreciated obobski.

I'll let you know how it goes

 

[Christobevii3]

I recommend the gizmo! It is what i use on my etl525's and another forum member is now using. It is built well, has an eq, variable sub out, and is more than enough power!

Link for Gizmo!

 

[mojaveviper]

I just purchased the pyle pta3 mini amp and it was delivered today, I will post the results when I hook it up and see what it sounds like. It will be driving a pair of Energy - C-100 - Bookshelf Speakers and a Energy - 10.3- Powered Subwoofer. It will be hooked up to the SoundBlaster Audigy 2 ZS sound card. if it dosent work out i will send it back.

Update: Well I hooked it up and have been listening to it for several hours now and in my opinion it is surprisingly good, it has pretty decent output, I have it turned up at a quarter turn its loud and has a good clean sound. the blue LEDs are VERY bright. but for a amp this small it sure Exceeded my expectations.

http://www.amazon.com/Pyle-2x75W-Stereo-Power-Amplifier/dp/B001P2R1RW

http://www.amazon.com/Pyle-PTA3-75-.../B001P2U6SS/ref=pd_cp_e_3/185-9335803-7798157

 

[SJetski71]

Ok, the only problem I see with those is that they have so little power. Your speakers would take up to around 100watts each max. I'm not saying blow them up, but that amp looks weak. Specially when you consider they are measuring at 4ohm, and your speakers take 8ohm. Ohm represents the resistance (impedance) a speaker has in receiving that power. Meaning that those 15watts and 40watts of the PTAs turn into a lower number once you hook your Insignias, because they will add resistance. You would still hear them, but probably not near the volume you enjoy.

I would look more into something like this: Mini Hi-Fi Stereo Amplifier ($14.99 + Shipping)
I'm not sure at what Impedance they measured, or if they are exaggerating the values, but that should give you more power. But be aware that's just a idea, I have not tried that item myself, nor done business with that vendor.
I'll would wait for someone with more knowledge in this area and give you a specific unit recommendation, but at least know you what to look for now.

Good luck.

That looks like the Lepai T-amp (Tripath based) discussed here. Considered a good amp for an inexpensive price, and it scales up nicely with mods. If it is the Tripath based amp then it's around 20watts x 2 @4ohm before distortion creeps in.

OP a $150 budget gives you tons of quality 2 channel amps to pick from. My advice would be to research before you buy, and go with something a little more proven.

Here's a forum that focuses on the DIY angle, but they also discuss lots of ready-made amps, especially the affordable ones: http://www.diyaudio.com/forums/forumdisplay.php?forumid=21

Here's a few more inexpensive class D amps. While some of them look raw, most of the actually just need a powersupply to get going (linear powersupplies and SLA batteries are often recommended).

1) Tripath 2050 100watt X 2: http://www.diyaudio.com/forums/showthread.php?threadid=143669

2) Lepai 25watt X 2: http://www.diyaudio.com/forums/showthread.php?threadid=90500

3) HLLy TAMP-90: http://www.diyaudio.com/forums/showthread.php?threadid=147589

I'm not necessarily recommending any of them, but i've read up on them and they seem pretty interesting. Personally i have a few sonic impact T-amp's, a few accurian amps, some tripath Ta2024 boards, and thinking about buying one of the Tk2050 based units i linked above. The Gizmo that ChristoBevi linked is also very popular. Not that i'm recommending them, but you can find those Pyle amps for a lot less here: http://www.parts-express.com/wizard...age=1&srchPrice=&srchCat=&srchMfg=&srchPromo=

 

[v3man]

I'm having trouble finding any thrift-type store that have receivers. Best option I could find so far was a Sherwood receiver for $89 at Radio Shack (somewhere along the lines of 8 ohms and 100W)

Update: Well I hooked it up and have been listening to it for several hours now and in my opinion it is surprisingly good, it has pretty decent output, I have it turned up at a quarter turn its loud and has a good clean sound. the blue LEDs are VERY bright. but for a amp this small it sure Exceeded my expectations.

Thanks for the update mojave! I'm thinking of just going with this one. I hope the return policy is ok just in case I don't like it

But feedback on that receiver or where I could locally find a store with a wide selection of audio equipment is still wanted. Best I have around here is like, Radio Shack and Best Buy etc... I'm from the Bay Area and would love to find a specialty store or something. I tried googling but maybe I just don't know the correct terms to use (i tried phrases like.. "audio specialty stores san mateo" or "mini/desktop amps san mateo" but to no avail)

EDIT: as for the DIY route, maybe if I had time to do all the research it entails I wouldn't mind going that route. But right now, I can't afford to have that on my already-never-ending hobby list

and thanks for the help everyone. keep it coming please

another edit... obobski, the link you gave me to the Big Joe, what about it makes it better than the Pyle? from that site it looks like at 8ohms, it only produces 8W
and would hooking up my speakers to a sub like this (or some variation of that) be the same/work?

 

[Jinto]

How well do these mini amps compare with older receivers? I have a Pioneer VSX-455 lying around which outputs 100w per channel. It is nearly 10 years old however.

I am looking at this one: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=120432058562

 

[obobski]

v3man: the Big Joe was just an example of a small, cutesy desktop amp, its probably higher quality than the Pyle overall, but other than that, generally nothing separates it (and I wouldn't doubt if the Pyle can put out more power)

as far as "how do these compare to old receivers", could be written "how do these compare to receivers":

if the receiver is good, theres no question, the receiver is better, except for size and power consumption issues

 

[SJetski71]

How well do these mini amps compare with older receivers? I have a Pioneer VSX-455 lying around which outputs 100w per channel. It is nearly 10 years old however.

I am looking at this one: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=120432058562

People buy and sell vintage receivers all the time, 10 years old isn't that bad. If it's a heavy receiver then there's a chance that it's an excellent receiver. Personally i say you try it out.

As for the amp in your link. It looks really nice and all of the parts have been upgraded. Those components aren't cheap and i'd bet the amp sounds great. The only issue i have with it is the low power of the amp (TA-2024 based). With 4ohm speakers it has a max of 11 usable watts, with 8ohm speakers it would have around 6 usable watts. That's pretty good if you have sensitive speakers, but if your speakers are NOT sensitive then it would only be good for nearfield, and wouldn't sound "room filling". It all depends on what speakers you want to pair it with.