Output impedance is important but only an issue if its highish. Output voltage is important to decide on following circuitry. With balanced and a 1V peak output there seems no need for a preamp - the gain of the TDA8566 is 26dB which gives 20V peak - i.e. already clipping.
Volume control is an issue - perhaps easiest to do this balanced with a quad-gang pot.
Volume control is an issue - perhaps easiest to do this balanced with a quad-gang pot.
I am sure not an expert on this topic.
Can you help on how I should connect the quad-gang pot with a diagram and what should be it's value?
I'd strongly prefer FreqResponse not depending on source impedance.
Can you help on how I should connect the quad-gang pot with a diagram and what should be it's value?
I'd strongly prefer FreqResponse not depending on source impedance.
Thinking out loud, I'm wondering now whether TDA8946AJ wouldn't be a better choice of chip for you as it already has a gain control built in.
I checked TDA8946AJ and it did not look very appropriate. It's designed for 18V Vcc and 8 ohm load. 12V power will only provide 4-5Watts much of which will have higher then %1 THD. And to sustain 12V I'll need a DC😀C converter which will make thing not only more complex but significantly less efficient.
PS: there is a chance that I'd drop to a 3 battery cell setup (10.8 to 9V) as most premade battery management circuits are for 3 cells.
PS: there is a chance that I'd drop to a 3 battery cell setup (10.8 to 9V) as most premade battery management circuits are for 3 cells.
I think you've got some misunderstanding about amplifier power output. Both of these chips are going to be limited by their supply voltage in the main, though its true into a 4R load the 8946AJ may well current limit (2A max). With only 12V supply its unlikely though. Apart from that potential current limit into lower impedances, the chips will perform identically in terms of power vs supply volts.
I rechecked and it looks like 8946AJ can only offer 9 watt in to 8 ohms @ %10 THD , that's a lot less then what 8566 is a blue to provide. Besides it will go down dramatically when battery voltage goes to 12V , forcing me insert a DC DC converter, which will then push me to figure out a way to filter out the ripples I guess.
The supply voltage for 9W into 8R is 14V (fig10, p10 of 8947AJ DS). I can't see a reason why the TDA8566 would deliver more power when running from the same 14V, can you?
I can see the figure of 25W on the front page, but that's into 4ohms, with 14.4V supply. Nowhere in the DS for TDA8566 do they give a spec for an 8ohm load.
There is no shortage of Class D kits out there and I might even have a few in my junk box.
Despite the fact that I invested in some hefty amplifiers, I wouldn't tell you that I can clearly hear a difference between a Class A and D amplifier at all as I have not done an A/B test with a Class D amplifier. However I'd like to test a battery powered Class AB amp for this project and I am well aware that with the same money/power I can get far more power and battery life from a Class D amp.
Despite the fact that I invested in some hefty amplifiers, I wouldn't tell you that I can clearly hear a difference between a Class A and D amplifier at all as I have not done an A/B test with a Class D amplifier. However I'd like to test a battery powered Class AB amp for this project and I am well aware that with the same money/power I can get far more power and battery life from a Class D amp.
i see.
http://www.nxp.com/documents/data_sheet/TDA1562Q_ST_SD.pdf
if you can, then try one of these.
from 14.4 supply it will deliver past 40 watt into 4 ohm.
before someoen tells me it is not possible..
it is a class H chip.
I repeat, class H.
it has internal circuitry enabling it to use supply lift capacitors.
one could consider the analogy of putting a step-up DC-DC converter and a class AB amp in one package.
http://www.nxp.com/documents/data_sheet/TDA1562Q_ST_SD.pdf
if you can, then try one of these.
from 14.4 supply it will deliver past 40 watt into 4 ohm.
before someoen tells me it is not possible..
it is a class H chip.
I repeat, class H.
it has internal circuitry enabling it to use supply lift capacitors.
one could consider the analogy of putting a step-up DC-DC converter and a class AB amp in one package.
That certainly looks like a TDA8566Q on steroids. Ability to set working mode is also quite attractive. Are there any drawbacks compared to TDA8566 that you are aware off?
And if you ever tried one of it, do you know if it does a mechanism to suppress pops and clicks during power on and off?
Additional question what are the Voltage ratings for the higher supply rails supply caps?
I will certainly give this baby a chance.
And if you ever tried one of it, do you know if it does a mechanism to suppress pops and clicks during power on and off?
Additional question what are the Voltage ratings for the higher supply rails supply caps?
I will certainly give this baby a chance.
I used 50 volt rated ones to be sure.
the 4700 uF lift caps are not realy enough in my experience.
i used 2x10,000 uF paralell 50 volt low ESR caps on the last one i built. quite a few years ago 😀
switchon popping does occur, You need to ramp the voltage on pin4 up slowly to avoid it.
a half secund will do, but keep in mind, if you employ a larger input dc block cap then you need to ramp the voltage slower. on poweroff, it should go immidietly to mute state. so voltage on pin 4 should be to zero very fast when powering it off.
the 4700 uF lift caps are not realy enough in my experience.
i used 2x10,000 uF paralell 50 volt low ESR caps on the last one i built. quite a few years ago 😀
switchon popping does occur, You need to ramp the voltage on pin4 up slowly to avoid it.
a half secund will do, but keep in mind, if you employ a larger input dc block cap then you need to ramp the voltage slower. on poweroff, it should go immidietly to mute state. so voltage on pin 4 should be to zero very fast when powering it off.
I think I can handle the mute thing, but not sure on how to provide a ramping up Vp, any help appreciated.
I am ordering both of the chip amps and a few more components, once they arrive I will open a new thread to ask many many more question.
Many thanks for helping me out.
I am ordering both of the chip amps and a few more components, once they arrive I will open a new thread to ask many many more question.
Many thanks for helping me out.
one more thing. Assuming that I'd be connecting various things from CD players to TV to a bluetooth receiver , should I use an opamp based preamp before the chipamp?
If so what would you recommend?
If so what would you recommend?
there is no need for a pre-amp.
the usualy things like mp3/cd player, computer, smarthphone, whatever.. they all have more than sufficient output.
refer to page 11 figure 7
http://www.hestore.hu/files/TDA8560Q.pdf
there you can see a circuit i used too.
it does a pretty darn good job.
the usualy things like mp3/cd player, computer, smarthphone, whatever.. they all have more than sufficient output.
refer to page 11 figure 7
http://www.hestore.hu/files/TDA8560Q.pdf
there you can see a circuit i used too.
it does a pretty darn good job.
- Status
- Not open for further replies.