TDA7293 single, bridge, parallel

[sudhir81]

My obsevations

• LM3886 has lower distortion levels compared to TDA7293.
• TDA7293 is more forgiving on mistakes, doesn't blow easily.
• Connecting TDA7293 in parallel is trivial. So higher power on lower impedances can be obtained very easily.
• TDA7293 features a lower power dissipation scheme with dual power supplies.

[panson_hk]

Originally Posted by carlmart

panson_hk,


By any chance, have you compared two things between the LM3886 and the TDA7393?

1) Audio quality

2) Sturdiness (comments from DIYers blowing it are not too reassuring)

I was considering doing a parallel/bridged amp with 3886, but they seem to have some limitations. But I wonder why this TDA, which apparently can provide higher power, was not as successful as the 3886.

Maybe for being poor on things above. Is that so?

Hi,

I have not seriously compared their audio performance. From data sheet and my measurement, LM3886 has lower THD. You may take a look of my experiment in this thread LM3886 parallel.

I find that LM3886 is more fault forgiving. An advantage of TDA7293 is that output resistor is not needed for parallel operation.

Panson

[carlmart]

Originally Posted by panson_hk

I have not seriously compared their audio performance. From data sheet and my measurement, LM3886 has lower THD. You may take a look of my experiment in this thread LM3886 parallel.

Your last chart seems very interesting, where you power 3 and 4 parallel 3886 chips with +/-40v.

Perhaps that could be applied on 3886 kits like this:

NEW DIY LM3886 x 3 Mono Audio Power Amplifier Board | eBay

I find that LM3886 is more fault forgiving. An advantage of TDA7293 is that output resistor is not needed for parallel operation.

What about the gain on each 7293? Has it to be trimmed too to be equalized on all chips?

Has anyone this Yuanjing kit? It seems to be the same on all eBay sellers.

[carlmart]

Sorry, the 7293 kit I was talking about:

TDA7293 Parallel 250W Mono Power Amp Board Kit NEW,Y25 | eBay

[sesebe]

hi Carlmart,

Check the datasheet of TDA 7293.

In paralel connections, for slaves IC's, you do not use the input part of the IC's. Only the output module are used in current amplifier configuration. The only inbalance will be in current sharing not voltage.

Bogdan

[geraldfryjr]

Any more updates on this project?

jer

[eXL]

Please, give the PCB on two, three TDA7293 in paralel.

[dr frost dk]

Nice work there, want another config to test on the TDA7293/94 do mine TDA7294 + Power Transistors AMP (TDA7293 to come also)
Would be nice to have some actual statistics on it, i have been using it (TDA7294) non-stop for 3+ Years now and it is REALLY REALLY good.

[CharlieLaub]

Originally Posted by eXL

Please, give the PCB on two, three TDA7293 in paralel.

User Danielwritesbac recently posted about a 2x parallel TDA7293 amp board available on Ebay, completely assembled. It uses the master + slave configuration of this IC so that no output resistors are needed.

I would love to see this design extended to 4 ICs and made available (on Ebay).

-Charlie

[danielwritesbac]

Originally Posted by CharlieLaub

Danielwritesbac recently posted about a 2x parallel TDA7293 amp board available on Ebay, completely assembled. It uses the master + slave configuration of this IC so that no output resistors are needed. I would love to see this design extended to 4 ICs and made available (on Ebay).
-Charlie

Trick: Put 220uF caps closely to the pre power pins of these chips and provide clean power. They will put so much less power into the heatsink that a surprising amount more power will then be available for the speaker. The dual and triple boards seems to attempt this. I do not know about the "seven" board.

Links:
Two parallel TDA7293
my build thread
Three parallel TDA7293
Seven parallel TDA7293

You can point to point for 4 chips:
First:
Mount 4 chips across the heatsink with thermal paste and pads. Bend all of the v- pins up near the chip face and install a rail across all 4 chips. Bend all of the v+ pins up Half that far and install a rail across all 4 chips.
Next:
The power ground rail is held by the following caps. . . Install some 220uF caps on the rails. Install some 47nF caps in opposing order on the rails. This makes a very rigid assembly in short order. Well, just like this concept except bigger and you'll need more caps since you have more chips. Add one 2uF 250v cap from v+ to v- at the same place where you attach power cable.
And:
Jumper all of the mute together and give it v+ via 12k. Jumper all of the standby together and give it v+ via 22k. Connect a 10uF or larger from standby to power ground rail. Follow the datasheet to finish up the slave chips. Hook up the boostrap cap (47u*4chips= use 220uF), and finish up the pilot chip like a standard op amp. Add some large capacitance quite close to the amp to help it manage the speaker return force.
Maybe the point to point takes 20 minutes?

Then again, the price for that 7 chip kit is really similar to the Mouser price for 4 chips. Of course soldering a seven chip kit will take a heck of a lot longer.
Unfortunately elevators in China don't stop on the 4th floor.

Other thoughts:
Be prepared to make a preamp--Bigger transformer for more powerful amplifier didn't make the computer bigger or more powerful. darnit!