Looking for class d, single supply, 4 Ohm, max power

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Buehgemeiste

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Joined 2013
#1
Hi,
for a subwoofer project i´m looking for class d boards which should be able to

- run on a single supply (24v prefered, anything else ok)
- work with 4 ohm speaker(s)
- output something around 100W (the more the better)

i already have this TPA3116:
TPA3116 Amplifier Assembled Board 50W + 50W Official Version Amp Board-in Amplifier from Electronics on Aliexpress.com

which is good for almost anything but driving a subwoofer towards higher levels.

and i have this TDA7498:
TDA7498 100W+100W Class D Amplifier Board High Power Amplifier Board-in Amplifier from Electronics on Aliexpress.com

which is good for a subwoofer, but not at 4 Ohm.

I know that there are TAS5630, IRS2092, TPA8950 and so on.
but they all need dual supply.

now i found this here:
Free Shipping Parallel TDA7498 2.0 power amplifier board (200WX200W) D Class Amplifier Board,Can connect 3 ohm speaker-in Amplifier from Electronics on Aliexpress.com
it seems to be an paralleled TDA7498.
i didn´t even know this was possible.

can someone confirm that it is possible to run TDA7498 in pbtl?
how would that be done with the black board above?

do i overlook a chip that would fit my needs?
 
#6
thanks for the replies.


xrk971 said:
Isn't the TPA3116 in PBTL mode capable of driving 100 watts into 2 ohms? Are you looking for 200 watts mono?
Click to expand...

i have one of the red 3116 modded to pbtl.
it still only gives 50W to 4Ohm.
100W is only into 2 Ohm with 24V supply.

xrk971 said:
One option is to use something like this with two 24 volt bricks to get dual rail supply but not mess with transformers.
Click to expand...

hmmm...two 24V bricks.
i think it's sure-electronics who sell 24V 5A smps for something like 15€ - 20€ including the shipping.
that's indeed an option.
today i got an offer for toroid transformers: 625W with 2xsec 60V.
2 available, 29,90€ each.
please help me think about it.

tonitonitoni said:
tas5630 dont need dual supply
Click to expand...

yes, your right.
but a closer look almost disqualifies those boards.
they are quite expensive.

TDA8950 120W+120W Class D Amplifier Board High Power Amplifier Board-in Amplifier from Electronics on Aliexpress.com

now, that's a cheap one.
when i have enough money for more sla batteries this could be ok for outdoor use.....
the cheap tda8950 plus two 24v smps seems to be the way of the budget so far.

i think this can be done with even less money....



edit:
oh no!!!
auswahl_034agshp.png

tda8950 won't really kick tpa3116's *** at 24V into 4Ohm.
 
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#7
I thought most boards came with a 12v regulator on board so all they'd need is a single 50v supply. Either that or use a 50v supply and buy a 12v supply, the 12v bit needs naff all current so it doesn't have to be expensive. And if you're handy with DIY you could cook up your own 12v reg from a TL783.
 
#8
5th element said:
I thought most boards came with a 12v regulator on board so all they'd need is a single 50v supply. Either that or use a 50v supply and buy a 12v supply, the 12v bit needs naff all current so it doesn't have to be expensive. And if you're handy with DIY you could cook up your own 12v reg from a TL783.
Click to expand...

Yes, you are right most have an on board regulator to get 12v. But the cost of the 50v single rail supply at 7a will kill this project according to the OP's budget constraint. A 7812 and a cap is all it takes.
 
#9
I have even wondered if two cheap 19v SMPS bricks can be paralleled to get 8 amps for $12 ( as bricks are only $6 ea). I started a thread to ask this previously. I think consensus is it may work IFF SMPS are identical and blocking diodes are used along with some low resistance load balancing power resistors. I have two bricks on order and will test.

Of course my first test will be to see if it works without diodes or resistors. 😀
 
Last edited:
#10
xrk971 said:
I have even wondered if two cheap 19v SMPS bricks can be paralleled to get 8 amps for $12 ( as bricks are only $6 ea). I started a thread to ask this previously. I think consensus is it may work IFF SMPS are identical and blocking diodes are used along with some low resistance load balancing power resistors. I have two bricks on order and will test.

Of course my first test will be to see if it works without diodes or resistors. 😀
Click to expand...

interesting!!

Buehgemeiste said:
Free Shipping Parallel TDA7498 2.0 power amplifier board (200WX200W) D Class Amplifier Board,Can connect 3 ohm speaker-in Amplifier from Electronics on Aliexpress.com
it seems to be an paralleled TDA7498.
i didn´t even know this was possible.

can someone confirm that it is possible to run TDA7498 in pbtl?
how would that be done with the black board above?
Click to expand...

as the board i posted in the op is only 11€ with shipping, i'm still in hope this might work.
and because i bought that for something like 16€ it's itching my fingers to compensate that with another order.
 
#11
Buehgemeiste said:
thanks for the replies.




i have one of the red 3116 modded to pbtl.
it still only gives 50W to 4Ohm.
100W is only into 2 Ohm with 24V supply.



hmmm...two 24V bricks.
i think it's sure-electronics who sell 24V 5A smps for something like 15€ - 20€ including the shipping.
that's indeed an option.
today i got an offer for toroid transformers: 625W with 2xsec 60V.
2 available, 29,90€ each.
please help me think about it.



yes, your right.
but a closer look almost disqualifies those boards.
they are quite expensive.

TDA8950 120W+120W Class D Amplifier Board High Power Amplifier Board-in Amplifier from Electronics on Aliexpress.com

now, that's a cheap one.
when i have enough money for more sla batteries this could be ok for outdoor use.....
the cheap tda8950 plus two 24v smps seems to be the way of the budget so far.

i think this can be done with even less money....



edit:
oh no!!!
auswahl_034agshp.png

tda8950 won't really kick tpa3116's *** at 24V into 4Ohm.
Click to expand...

You forgot that if you doubled up with two 19 v bricks for 38 volts maybe you can get 150 watts.
 
#13
can someone please comment those boards:

http://www.aliexpress.com/item/Prom...00-W-Finished-amplifier-board/1623135172.html
and

DC15V 36V D level TDA7498 D Dual Channel 80Wx2 Class D Stereo Audio Amplifier-in Amplifier from Electronics on Aliexpress.com

their description says 4 ohm is possible.

edit:
and there are these, which sell for 11€ incl shipping on ebay:
http://www.aliexpress.com/item/TDA7...shed-grade-fever-Class-D-HIFI/1878358339.html
(foreign ebaylinks usually suck, so i waste your time with reading this, instead of following a dead link...)
 
Last edited:
#17
the description on ebay includes the following:

TDA7498 chip with our board reasonable elegant layout, and the collocation of all kinds of high quality components, such as: special customized digital power amplifier for large current shield inductance, philips, nichicon fever, high frequency high temperature and low resistance capacitance, original samsung SMD SMD components and so on. The power amplifier circuit board is simple, reliable work. Power supply voltage 15 v to 36 v (voltage suggest not more than 36 v), maximum output 100 wx2, calorific value is small, efficiency is above 90%. Can use the switch power supply, also suitable for battery or battery power supply of portable electronic products. TDA7498 amplifier plate volume is small and exquisite, very flexible and convenient use and install, all the components use authentic devices, can be competent for long-term and stable work.
Boards are finished plate welding test, just need to turn on the juice and speakers and audio source can be used. 8ohms load proposal within 35 v power supply voltage, 4ohms load proposal within 24 v power supply voltage, 4ohms in parallel mode power supply voltage can use 36 v of this board design the reverse protection, will not lead to burn for pick up anyway, negative amplifier board components.
Click to expand...
 
#18
Buehgemeiste said:
ok, st508 is also an option.

2 X 100 Watt 4 Ohm Class D Audio Amplifier Board - STA508 100W Stereo T-Amp | eBay

too bad there are no other option than this one with the propeller.

my noob brains do not know why, but something about the blue (first in my previous post) TDA7498 is sexy.
Click to expand...

Yes, the propeller is certainly not ideal. People have had good results with big Zalman fanless heatsinks. I may try one.

Note: I have no idea how/why I quoted myself above, please ignore.
 
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