Hello everyone
I'm fresh on these forums, so forgive me if I placed this thread in the wrong section.
Anyhoo, I got these speakers some years ago, used and really cheap. And what bothered me from day 1 was that the maximum volume I get from them is only about 50 / 55 %, any more and I get horrible screeching distortion from the sattelites and the subwoofer seems to lose its kick as well. I talked to my friend who has the same speakers and he said he could turn them up far beyond my level, and some YT videos I watched also seemed to prove the point.
After some time I tried switching the stock 8ohm sattelites with some 6ohm bookshelves, just to test if the situation would be any better, but it wasn't.
I then figured the integrated amplifier must have been ran too hard for too long sometime in the past by the previous owner and it got damaged? I haven't got a clue what else could be causing this problem. I doubt it could be the toroid transformer...
Now, I haven't opened the thing just yet, but I do already have a general idea what it looks like, and what I think would be a possible candidate for replacement.
Here's some pics of the amplifier circuitry and toroid transformer.
TRAFO : Imgur: The most awesome images on the Internet
AMP : Imgur: The most awesome images on the Internet
Looking at the last picture I was thinking of replacing the bulk caps(blue) and the amplifier chips(red). Of course when I open the thing myself I'm gonna see if there's any other bad capacitors and replace those too. But for now, my knowledge only goes as far as bulk caps and amp chips. Is there anything else I should think about?
Another option is also using a dedicated external amplifier to drive the speakers and the sub driver itself, but that seems a lot more complicated at this point, plus I wouldn't be able to use the volume/remote pod.
I'm fresh on these forums, so forgive me if I placed this thread in the wrong section.
Anyhoo, I got these speakers some years ago, used and really cheap. And what bothered me from day 1 was that the maximum volume I get from them is only about 50 / 55 %, any more and I get horrible screeching distortion from the sattelites and the subwoofer seems to lose its kick as well. I talked to my friend who has the same speakers and he said he could turn them up far beyond my level, and some YT videos I watched also seemed to prove the point.
After some time I tried switching the stock 8ohm sattelites with some 6ohm bookshelves, just to test if the situation would be any better, but it wasn't.
I then figured the integrated amplifier must have been ran too hard for too long sometime in the past by the previous owner and it got damaged? I haven't got a clue what else could be causing this problem. I doubt it could be the toroid transformer...
Now, I haven't opened the thing just yet, but I do already have a general idea what it looks like, and what I think would be a possible candidate for replacement.
Here's some pics of the amplifier circuitry and toroid transformer.
TRAFO : Imgur: The most awesome images on the Internet
AMP : Imgur: The most awesome images on the Internet
Looking at the last picture I was thinking of replacing the bulk caps(blue) and the amplifier chips(red). Of course when I open the thing myself I'm gonna see if there's any other bad capacitors and replace those too. But for now, my knowledge only goes as far as bulk caps and amp chips. Is there anything else I should think about?
Another option is also using a dedicated external amplifier to drive the speakers and the sub driver itself, but that seems a lot more complicated at this point, plus I wouldn't be able to use the volume/remote pod.
These are simple computer speakers,you can't expect wonders,but you could try using an external amp, or changing the plate amp.
This is a cheap system, with two satellites using a 2,5" (cheap) full range and a (cheap) 8" woofer. Including three amplifiers for $100 or so.
You are simply running into the laws of physics here. The full range sattelites has to be crossed over at 200hz or less, so there's a limit on how loud these can go, before they're starting to distort.
Are you very low on the volume control on the pod? You might be overdriving the opamps with a too loud signal from your source...
As a replacement amp, maybe a Hypex UcD34MP will do. That's a class D 4x30W amp with integrated psu. You'll need to gut some of the electronics from the Logitech plate amp, as you're going to need the input buffer and the crossover. These amps are on end of product life sale now at €65.
Johan-Kr
You are simply running into the laws of physics here. The full range sattelites has to be crossed over at 200hz or less, so there's a limit on how loud these can go, before they're starting to distort.
Are you very low on the volume control on the pod? You might be overdriving the opamps with a too loud signal from your source...
As a replacement amp, maybe a Hypex UcD34MP will do. That's a class D 4x30W amp with integrated psu. You'll need to gut some of the electronics from the Logitech plate amp, as you're going to need the input buffer and the crossover. These amps are on end of product life sale now at €65.
Johan-Kr
Or maybe something like this would be even easier - it's on sale right now...
Dayton Audio MCA2250E 2.1 Channel Class D Plate Amplifier
Dayton Audio MCA2250E 2.1 Channel Class D Plate Amplifier
Well as I said, the external amplifier is a bit more complicated, so I will only resort to one if there isn't any other alternative. Also, the one that you linked is seriously underpowered, as my subwoofer alone is rated 120WRMS, and then also add (at least) 2x40WRMS for the speakers.
As for the crossover @200Hz, I don't know what the frequency range has to do with power? If you could explain this a bit better to me?
@Overdriving amps with too loud signal - Both me and my friend drive our speakers from PCs, and I doubt that there would be such a difference in signal amplitudes between different PC motherboards.
I also have the option of driving the speakers from PC integrated soundcard, and a dedicated ASUS Xonar soundcard, and the distortion starts at the same volume in both cases.
As for the crossover @200Hz, I don't know what the frequency range has to do with power? If you could explain this a bit better to me?
@Overdriving amps with too loud signal - Both me and my friend drive our speakers from PCs, and I doubt that there would be such a difference in signal amplitudes between different PC motherboards.
I also have the option of driving the speakers from PC integrated soundcard, and a dedicated ASUS Xonar soundcard, and the distortion starts at the same volume in both cases.
Well - Logitech states that it is 120Wrms. I pretty much suspect that rating to be like boomblaster watts, and be more like 20-30 "real" watts.
Those dinky 2,5" fullrange speakers can handle maybe max 10-15 proper watts. More probably max 10.
To get 3dB more volume you have to increase power by a factor of 10. So those 120 watts aren't all that much more than 30W. Also, you can bridge two channels to run the woofer.
Atm, I'm testing a UcD32, using it to power a pair of Kef Reference three, with two 8" woofers, one 6,5" midwoofer and a 6,5" coax per speaker.
It can play quite loud without any problems.
There shouldn't be much difference between soundcards, so the amp is most likely defective. However, it's an easy test to eliminate if the problem is the input buffer. Simply turn down the soundcard and turn up the volume on the speakers.
Johan-Kr
Those dinky 2,5" fullrange speakers can handle maybe max 10-15 proper watts. More probably max 10.
To get 3dB more volume you have to increase power by a factor of 10. So those 120 watts aren't all that much more than 30W. Also, you can bridge two channels to run the woofer.
Atm, I'm testing a UcD32, using it to power a pair of Kef Reference three, with two 8" woofers, one 6,5" midwoofer and a 6,5" coax per speaker.
It can play quite loud without any problems.
There shouldn't be much difference between soundcards, so the amp is most likely defective. However, it's an easy test to eliminate if the problem is the input buffer. Simply turn down the soundcard and turn up the volume on the speakers.
Johan-Kr
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I just found the specs on the unit - As I suspected: Woofer: 120W at 1kHz at 10%THD. Satellites 40W at 1kHz at 10%THD. Boomblaster specs, indeed...
Johan-Kr
Johan-Kr
Well if that's the case with the power rating, that sure makes me happy, cause it means I don't need some unholy powerful amplifier. But Fenalaar are you sure about these power ratings? I would hate to buy an external amp that couldn't handle these speakers.
I went to a local ebay-like site and saw lots of car amplifiers going for as low as 20EUR, and I wonder if I could make use of one? For example, I saw a sony xm4040 for 35EUR, and it's rated 40W per channel, and it has 4 total channels. Seems to me, there is nothing preventing from using one for these PC speakers? I would just have to route the sub driver's connectors out/to the rear panel, and then come up with a way for crossovers and such stuff that I know nothing about haha 😀
Or even use a hi-fi amplifier perhaps?
Before you guys start scrutinizing me for these ideas, look - I'm on a budget here, as I mentioned I got these speakers for dirt cheap, I think it was 30EUR, and it's in no way in my interest to spend around 100EUR just to get an amp for them.
Thanks for all the advice so far Fenalaar 🙂
I went to a local ebay-like site and saw lots of car amplifiers going for as low as 20EUR, and I wonder if I could make use of one? For example, I saw a sony xm4040 for 35EUR, and it's rated 40W per channel, and it has 4 total channels. Seems to me, there is nothing preventing from using one for these PC speakers? I would just have to route the sub driver's connectors out/to the rear panel, and then come up with a way for crossovers and such stuff that I know nothing about haha 😀
Or even use a hi-fi amplifier perhaps?
Before you guys start scrutinizing me for these ideas, look - I'm on a budget here, as I mentioned I got these speakers for dirt cheap, I think it was 30EUR, and it's in no way in my interest to spend around 100EUR just to get an amp for them.
Thanks for all the advice so far Fenalaar 🙂
Car amps are not really good, because you'll need a beefy 12-14VPSU for them.
You probably got the speakers for cheap, because they were partially broken.
My stepson has a Logitech Z-something set, that started out as a 5.1. The sub still works, but he only has one working sattelite and the center left, so now I'm building him a line array with one UcD34 per side, and a whole bunch of Peerless/Vifa TC9FD18 3 1/2" full range speakers per side... Those satellites really take a beating.
Johan-Kr
You probably got the speakers for cheap, because they were partially broken.
My stepson has a Logitech Z-something set, that started out as a 5.1. The sub still works, but he only has one working sattelite and the center left, so now I'm building him a line array with one UcD34 per side, and a whole bunch of Peerless/Vifa TC9FD18 3 1/2" full range speakers per side... Those satellites really take a beating.
Johan-Kr
I tore apart a different Logitech model for parts after its controller died. Plenty of decent parts in there. You could do worse than playing around with doing a decent point-to-point implementation of the chip amps in there--that might remove the offending part. Choosing minimum gain of the chip amp might help minimize the issue (they probably have too much gain)
Unless, of course the chip amps are themselves busted.
Unless, of course the chip amps are themselves busted.
So what would be a good choice to replace these ageing speakers? I'm thinking of spending somewhere in the 100EUR range. Please keep in mind, I do want the max bang for my buck, I don't need some super quality monitors that aren't all that loud. I prefer loundess over quality.
I do not see any Heat Sinks ??
Chips like these, they need heatsinks. If not, they will whisper, maybe play moderate, but at high levels they cook and shut themselves down. Sometimes not in a pleasant way.
Chips like these, they need heatsinks. If not, they will whisper, maybe play moderate, but at high levels they cook and shut themselves down. Sometimes not in a pleasant way.
> Satellites 40W
The PT says two 20V windings. Comes to +/-28V. No-sag that would be 50 Watts in 8 Ohms. With typical sag something below 40W before clipping. The 10% THD spec is taken somewhat into clipping.
The specs are honest enough for consumer products.
They can probably be pretty loud at a few Watts. That they punk-out may go back to flawed or missing heatsinking.
The PT says two 20V windings. Comes to +/-28V. No-sag that would be 50 Watts in 8 Ohms. With typical sag something below 40W before clipping. The 10% THD spec is taken somewhat into clipping.
The specs are honest enough for consumer products.
They can probably be pretty loud at a few Watts. That they punk-out may go back to flawed or missing heatsinking.
The whole black panel that the amp is mounted on, is the heatsink. It's a pretty hefty one, here's a picture from the backside
You can also see that the chip amps that I marked in red circles are mounted on the heatsink, with the white thermal paste being pretty obvious.
You can also see that the chip amps that I marked in red circles are mounted on the heatsink, with the white thermal paste being pretty obvious.
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