Hi All ;
I have started on building a decent semi portable speaker system. At this stage I am focused on the amplifier part.
It will be connected to 2 way 2.0 speakers of fine quality. Speakers are around 86-87db and I don't feel the need to rock the whole world so I am fine with 10 watts of clear amplification that can reach 15-20 watts when needed. %90 of the listening will be around 4-5 watt region.
I am more biased towards using a Class AB amp versus A T or D but honestly I never id an A-B test between Class D and AB chip amplifiers.
Of all the chips I had a look, my favourite is TDA8566 , not only it seems to have enough power event at 6V supply rail. Single power supply rail and BTL architecture seems to suit my needs.
However I have no idea about how this chip sounds nor I had been able to find it's power consumption figures. (I am more interested in efficiency graphics for 4 ohm speakers)
I think that I will be able to squeeze in a 60Whr battery inside and I'd like to know how much it will last at 4W/hr output per channel.
Any help will be appreciated.
Mertol
I have started on building a decent semi portable speaker system. At this stage I am focused on the amplifier part.
It will be connected to 2 way 2.0 speakers of fine quality. Speakers are around 86-87db and I don't feel the need to rock the whole world so I am fine with 10 watts of clear amplification that can reach 15-20 watts when needed. %90 of the listening will be around 4-5 watt region.
I am more biased towards using a Class AB amp versus A T or D but honestly I never id an A-B test between Class D and AB chip amplifiers.
Of all the chips I had a look, my favourite is TDA8566 , not only it seems to have enough power event at 6V supply rail. Single power supply rail and BTL architecture seems to suit my needs.
However I have no idea about how this chip sounds nor I had been able to find it's power consumption figures. (I am more interested in efficiency graphics for 4 ohm speakers)
I think that I will be able to squeeze in a 60Whr battery inside and I'd like to know how much it will last at 4W/hr output per channel.
Any help will be appreciated.
Mertol
TDA8566 is class B, which means there is no class A bias. People like class A bias. 🙂 But class B is more efficient and cool running, but potentially more susceptible to crossing distortion as the pushing transistor shuts off after positive waveform, while the pulling transistor simultaneously turns on to create the negative half of the waveform. This switching on and off saves power and heat but can make spikes in the output waveform called crossing distortion. Other much older NXP (previously Philips) chip amps (class AB) that I've used have fairly significant crossing distortion seen on a scope, but I think this is one of the reasons it sounds "alive, exciting and airy." Newer chips are probably even better at reducing crossing distortion. The purpose of class A bias is to eliminate this crossing distortion. But chip amps have limited ability to dissipate the added heat that class A generates.
It is important to know what load your speakers will present to the amplifier. That determines the current draw needed from the amp to drive the speakers, and whether a battery powered chip amp can source than much current. If it can't deliver the current, it will enter protection mode. Most chip amps have a protection mechanism and it always sounds very bad, so you want to make sure that the amp always, under worst case max party-mode conditions will never enter protection mode. It doesn't hurt anything but it really sounds bad. The Philips chip I once used sounded like digital clipping in protection mode. But I was driving 2.9ohms dip speakers with 8ohm rated 5W chip. 😀 It sounded excellent as long as not too loud. TI's Overture chip amps' (gainclone amps, etc) protection is called Spike and it sounds terrible. Your TDA8566 says it can handle 2ohm loads, so that is good. It makes only 0.5% THD at 30w into 2ohms with 14.4VDC (that is a car battery being charged with engine running.) So it looks good for your application with a small motorcycle battery or small stack of lithiums?
Just be sure to read the spec sheet carefully and pay special attention to the test circuit recommendation, and adequate heat sinking to avoid the overheat protection. Good luck!!!
It is important to know what load your speakers will present to the amplifier. That determines the current draw needed from the amp to drive the speakers, and whether a battery powered chip amp can source than much current. If it can't deliver the current, it will enter protection mode. Most chip amps have a protection mechanism and it always sounds very bad, so you want to make sure that the amp always, under worst case max party-mode conditions will never enter protection mode. It doesn't hurt anything but it really sounds bad. The Philips chip I once used sounded like digital clipping in protection mode. But I was driving 2.9ohms dip speakers with 8ohm rated 5W chip. 😀 It sounded excellent as long as not too loud. TI's Overture chip amps' (gainclone amps, etc) protection is called Spike and it sounds terrible. Your TDA8566 says it can handle 2ohm loads, so that is good. It makes only 0.5% THD at 30w into 2ohms with 14.4VDC (that is a car battery being charged with engine running.) So it looks good for your application with a small motorcycle battery or small stack of lithiums?
Just be sure to read the spec sheet carefully and pay special attention to the test circuit recommendation, and adequate heat sinking to avoid the overheat protection. Good luck!!!
Thanks a lot for the comments. I actually read everything I could find. (I can't say that I understood everything fully)
I have 2x300W Class A's downstairs driving NS1000M's happily but powering Class A amps from battery would be an overkill. Actually even powering Class AB is an overkill where D offers %80+ efficiency.
My speakers will be presenting an almost flat 4 ohms to the amp.
I plan to use a stack of Lion or Lipo, my initial plan is to use a laptop battery (10.8 or 14.4 V)
I found TDA8566 as it does require single supply rail (two rails in a battery powered system is way too complex for me) and is BTL meaning no output caps to worry about.
Mostly I am worried about power consumption right now and DS lacks those figures.
br
Mertol
I have 2x300W Class A's downstairs driving NS1000M's happily but powering Class A amps from battery would be an overkill. Actually even powering Class AB is an overkill where D offers %80+ efficiency.
My speakers will be presenting an almost flat 4 ohms to the amp.
I plan to use a stack of Lion or Lipo, my initial plan is to use a laptop battery (10.8 or 14.4 V)
I found TDA8566 as it does require single supply rail (two rails in a battery powered system is way too complex for me) and is BTL meaning no output caps to worry about.
Mostly I am worried about power consumption right now and DS lacks those figures.
br
Mertol
TDA8566 can sound awesome with enough attention to the power supply. Its idle current is about 110mA so from the minimum 6V supply this is a quiescent draw of 660mW. You'll not get 10W out of it though running at 6V.
If you're concerned about battery life, the best solution is classD - try TDA8932 - it needs at least 10V.
If you're concerned about battery life, the best solution is classD - try TDA8932 - it needs at least 10V.
I am more concerned at the sound quality but I'd like to have 3+ hours from a 60-70watthr battery if possible when driving 2 channels at an average of 4 watts.
So it looks like I will be in need of %50 efficiency which may not be possible if I feed it with 12V and only demand 4 watt. It's a pity that Philiphs did not include those efficiency figures.
My initial plan is to use 2p4s battery setup. That should give me 14.8 to 12V.
(not sure if it's worth using a DC😀C buck/boost to fix the Vp to 14V)
I had never done a battery powered amplifier before and not sure how the power supply will look like. I need to study a little bit on the battery management systems.
PS: 4 watt @ 88DB is fairly loud compared to current portables which average at 2-3 watt @ 80 DB but I don't think that Class AB amplifiers get any efficient with lower output (i.e. 1 watt output almost takes %80 of 3 watt output)
Opps my mistake. 2 x 4watts = 8 watts and 3 hours makes it 24watts so it should indeed be possible with a 60 watt-hour battery pack. And I think 70watthour is possible with 2p4s setup with 2650mAh 18650 cells.
What music are you playing that will average 4W output? Even the most compressed grunge on the planet has a crest factor (peak to average) of 10dB, most is a few dB more than this. So for an average of 4W you'll need at least a 40W amp.
ClassAB are extremely inefficient at lower power outputs, which is why for battery power I suggest classD.
As a handwaving exercise based on my own experience with the chip, if you ran your TDA8566 from 12V you could expect an average current under 1.5A when playing unclipped music into 4ohms so you'd get 3hours use from a 60Wh pack.
ClassAB are extremely inefficient at lower power outputs, which is why for battery power I suggest classD.
As a handwaving exercise based on my own experience with the chip, if you ran your TDA8566 from 12V you could expect an average current under 1.5A when playing unclipped music into 4ohms so you'd get 3hours use from a 60Wh pack.
You are right on that. I think my average will be less then 4 watt. Right now my sony peak program meter on the TAE-8450/TAN8550 combo rarely touches 1 watt.
After a bit of search despite relatively high cost I will use a 4S (four serial) Lipo 10,000 mAh; which I think can give 5-7 hours , far more then enough for a semi portable that won't travel too far from an outlet usually.
So , I'd better start getting bits together.
One question. I see several TDA8566Q2s sold from China at 1-2USD piece which is 4x less expensive then the usual price. Do you think that they are fake ?
After a bit of search despite relatively high cost I will use a 4S (four serial) Lipo 10,000 mAh; which I think can give 5-7 hours , far more then enough for a semi portable that won't travel too far from an outlet usually.
So , I'd better start getting bits together.
One question. I see several TDA8566Q2s sold from China at 1-2USD piece which is 4x less expensive then the usual price. Do you think that they are fake ?
I've bought quite a few TDA8566s here in China, none have turned out to be fakes yet. They are recycled ones - my latest have been marked 'Bose'. I've been paying less than $1 too 😀
I roll my own TDA2822M Amp, that does 1 watt in monaural mode.
I'm very happy with the sound that it makes in stereo, can hardly wait until my mono version is done.
I'm very happy with the sound that it makes in stereo, can hardly wait until my mono version is done.
I've been modifying some low end car amps lately that have Toshiba TA7250 , or the more common TA8210 in them, and have been very pleased with the outcome. The super clean and detailed output into some 4ohm, 4" bookshelf speakers is hard to beat for the price and effort. There is actually some perceivable bass also, very balanced sound.
There are several companies like "Jensen", or Audiovox that made or still make these, and aren't worth much for car use, considering that most head units will have the same output. They have protection circuitry too.
Ive paid $10 from local classifieds, or thrift stores, then modify with surplus Silmic Super Gold, Panasonic Purism, and some Wima FKP1 for smaller values. I have built up power supplies with additional line filtering, but for portable use that part would be much easier...
There are several companies like "Jensen", or Audiovox that made or still make these, and aren't worth much for car use, considering that most head units will have the same output. They have protection circuitry too.
Ive paid $10 from local classifieds, or thrift stores, then modify with surplus Silmic Super Gold, Panasonic Purism, and some Wima FKP1 for smaller values. I have built up power supplies with additional line filtering, but for portable use that part would be much easier...
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if i was You...
TPA3123 Digital Stereo Amplifier Class D Power Amp Kit Mini Audio Module 25WX2 | eBay
get one of those.
runs from anything between 10 and 30 volts.
3 piece of 9 volt rechargable batter will give you 27 volts.
there is your battery pack then, slap on 2*(3 in series) 9 volt recharable battery, and You are good to go.
i ran a class AB amp from 3x4.5 dry pattery packs for over a week in the workshop.
the mentioned stuff is class D, You will get quite a few hours of loud music.
best is, you can get charger and and batterys too pre-made.
wire it up and good to go.
TPA3123 Digital Stereo Amplifier Class D Power Amp Kit Mini Audio Module 25WX2 | eBay
get one of those.
runs from anything between 10 and 30 volts.
3 piece of 9 volt rechargable batter will give you 27 volts.
there is your battery pack then, slap on 2*(3 in series) 9 volt recharable battery, and You are good to go.
i ran a class AB amp from 3x4.5 dry pattery packs for over a week in the workshop.
the mentioned stuff is class D, You will get quite a few hours of loud music.
best is, you can get charger and and batterys too pre-made.
wire it up and good to go.
Please note that when using the asymmetrical supply mode in combination with BTL operation you will need 2 pieces of TDA8932 for stereo.
+1 altough this chip also assumes SE operation rather then BTL so there is a power penalty and for stereo you will need 2 pieces if set to BTL mode
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he is going to drive 4 ohm rated stuff.
BTL in this case would not be a good idea.
no need for 2 of these chips, nor any servo at all.
it does alone 25w/ch into 4 ohm from a 27 volt supply.
http://www.ti.com/lit/ds/symlink/tpa3123d2.pdf
read the pdf 😀
it seems the stuff is 100% suited for the demand of the OP.
BTL in this case would not be a good idea.
no need for 2 of these chips, nor any servo at all.
it does alone 25w/ch into 4 ohm from a 27 volt supply.
http://www.ti.com/lit/ds/symlink/tpa3123d2.pdf
read the pdf 😀
it seems the stuff is 100% suited for the demand of the OP.
And TDA8561 (single ended)
Don't leave the poor boy hangin':
single ended/balanced:
single ended:
These are 'special' amps (AFA), see 'braxy's circuits at:
http://www.diyaudio.com/forums/part...plifier-ad830-lt6552-tda856x.html#post3392698
😎
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I think I am set to start with TDA8566 , easy to find , easy to implement. What would you guys recommend as the preamplifier?
Plan is to have multiple inputs to support a general purpose AUX and an internal bluetooth adapter.
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