Replacing a pair of TDA2030 to increase power

[sivan_and]

I need to replace a pair of TDA2030 (subwoofer amp in BTL ) to increase power any pin to pin replacement ? (can be National semi, texas inst, Burrbrown, or SGS any suggestions ?

[Mooly]

Power output is determined by the supply voltages used rather than the actual device.

[sivan_and]

i can increase voltages upto dual 30 volts.....but what am asking is in the same package dimensions and pin layout..which IC can sink max power output...i know TDA2050 LM1875 are better...but in BTL mode can they deliver the increased current ?

[Mooly]

You might like to read this,
App Note - Bridging Power Audio Amplifiers

As to what devices are suitable, pin for pin wise, I don't know without researching them all.
The TDA2030 is ancient, they were causing grief quarter of a century ago, and any modern device is way better.

[Xoc1]

The last TDA2030 I replaced I subtituted a TDA 2050.
It was a small guitar amp that had blown the 2030.
I would think given that these amplifiers have thermal limiting circuits to enable use on inadequate heatsinks, that you might find there are performance gains from improving the cooling . I strapped on a extra finned aluminium heatsink, and that made the difference!

[navin]

Originally Posted by sivan_and

i can increase voltages upto dual 30 volts.....but what am asking is in the same package dimensions and pin layout..which IC can sink max power output...i know TDA2050 LM1875 are better...but in BTL mode can they deliver the increased current ?

Sivan, How did the project go.

I am looking to bridge 2 1875 chips I have aorund to drive a small 6" woofer. Trouble is I cannot find a BTL schematic for the 1875.

What kind of output should I pexect from a BTLed pair of 1875 - I am using a 24V DC power supply. I suspect I should get in the region of 50W rms @ 8 ohms (I dont think the BTL pair should be asked to drive lower impedances).

[abraxalito]

The chip looks limited to 20W into 4R so bridging it will give 40W into 8R. You're right, you shouldn't go lower than an 8R load when bridging with these chips.

To bridge two 1875s, either use a cross-connected differential amp config. for both, or add an opamp inverting stage to one of the amps.

<edit> On second thoughts, in this case you're not using a high enough supply voltage to get the 40W - probably only 20W is achievable with the single 24V.

[navin]

Originally Posted by abraxalito

To bridge two 1875s, either use a cross-connected differential amp config. for both, or add an opamp inverting stage to one of the amps.

<edit> On second thoughts, in this case you're not using a high enough supply voltage to get the 40W - probably only 20W is achievable with the single 24V.

The object of using 2 1875s in BTL was to be able to use the same power supply for the sub channel and left/right (stereo 1875) channels.

This project is part of a small boom box I am building my son for his ipod. Oh I know there are many ipod speakers on the market but few have the features he wants (dual ipod, cd player input, line out, remote volume control, etc..). The idea is to have 4 1875 powered by one power supply. 2 would be bridged to drive a subwoofer and the other 2 would drive the left and right speakers.

The "sub" is actually a 6" 8ohm woofer which should go as low as 50Hz in about 1/3 cu. ft. The mains are 3" fullranges similar to TB's 871.

For the power supply I was thinking of using a 300VA 18V transfomer which when rectified would give me 24V DC. 300VA would be adequate for 4 1875s or even 2 1875 + 1 3875.

Is it then recomended that given my power supply limitations that I use a 3875 for the subwoofer and 2 1875 for the right and left speakers?

[sangram]

24V rails will give you a little more than 100W bridged provided your PSU can deliver enough current and your heatsinks can keep up. You can expect to swing around 30-32 volts at the output with the right chips (say a pair of TDA 7294 in bridge mode).

There is a method to bridge without having to resort to inverting configuration on one of the chips or a bridge adapter. Look at the ESP site, it's a single resistor from the output of one chip to the inverting input of the second chip. The second chip operates in slave mode so its niput is grounded. For subwoofer applications, this works very well indeed.

A single 3875 will offer no advantage over a single 1875 with the same supply voltage and input signal

[abraxalito]

Originally Posted by navin

For the power supply I was thinking of using a 300VA 18V transfomer which when rectified would give me 24V DC. 300VA would be adequate for 4 1875s or even 2 1875 + 1 3875.

So what's the reason behind going for a single polarity supply, rather than +/- rails?