Two cheap TDA7293 boards in bridge

[echelion]

Hello!

Can I use two of this and make a bridge conection? ZHITING TDA7293 Mono Amplificador de Potencia de Audio Digital monocanal Junta AC 12-32V 100W: Amazon.es: Electronica

I can get it very cheap and have it with the advantages of prime

 

[rayma]

Yes, but while the output voltage will double, the current output will remain the same.
If you have higher impedance speakers, 8 ohms or more, it should work.
You'll need a unity gain op amp inverter for the negative phase input.

 

[echelion]

Thanks for your very fast response!

My idea is replace the amplifier of a ALTO Profesional PS4LA blown amplifier....it used 3 LM3886 two in BTL for a 100w 4 ohm 12 inch speaker + one to 30/40w driver 16 ohm

Its a good idea? I never use the TDA7293....maybe its enough with only one?

Other option is use one of this and bridge too? 3886 HiFi Dual TF amplificador estereo montado placa amplificadora 68W Modulo de amplificador de potencia de Audio placa TF placa amplificadora de potencia|Accesorios y piezas para instrumentos| - AliExpress

Maybe is enough with invert the input?

 

[Michael Bean]

The LM3886 CANNOT be bridged into a four ohm load...not many chip amps can handle two ohm loads, which is what a four ohm load looks like to each amp in the bridge.

Mike

 

[chermann]

Hi


have a look into the datasheet of the 7293 at figure 16.
here are the maximal conditions for 4R load(resistive load!) as you can see the max supply voltage is +/- 29V at the rails and then you get out about 75Watt with perfect cooling.
chris

 

[nigelwright7557]

Bridging is good but i have never been a fan of paralleling amps.

 

[echelion]

The LM3886 CANNOT be bridged into a four ohm load...not many chip amps can handle two ohm loads, which is what a four ohm load looks like to each amp in the bridge.

Mike

Hi!!

I think Alto Profesional did it...look for Ps4-la service manual...and i have a couple in front of me just now :s.

 

[Michael Bean]

OK...you are the expert.

Mike

 

[Panelhead]

To help a bridge chip amp with driving normal loads try a lower voltage transformer. Even an 8ohm speaker may be 4 - 5 ohms at some frequencies. As long as this is not in the bass region it should be fine.

 

[joydivision]

echelion: I've used TDA7294/93 in the past (three of my home made amps are based on this chipamp) with great success, it's a very easy to implement, robust and great sounding chip. So, I'd go for it. And I'd choose it over the LM3886 (have also used and implemented with success. Sounds great, but has much higher tendency to start oscillating, for example). But: careful with bridging, as already has been advised, avoid 4 ohm loads (would look like 2 ohm to each module, high heat generation and might trigger internal shutdown). In fact, Michael Bean said very well: datasheet of LM3886 says not to use bridge mode with 4 ohms loads. I happened to use it one time just for test purposes, it will work, but only for very reduced power output and lower voltage rails, you CAN'T drive it up, massive heat generation and would trigger shutdown, unless maybe some extreme cooling measures. TDA729x is similar in respect to this. Bottom line: if you want to drive only 8 ohm speakers, your plan will work fine, but need good heat sink and careful with voltage of transformer. If 4 ohm, you would be limited in volume, which means it doesn't even make sense to use bridged mode at all for that.

 

[Kay Pirinha]

Of course you can bridge TDA729x's as well as LM3886's and feed 4 ohms loads. Anyway, depending on the supply voltage you need to double, triple etc. the devices on each side. Tom Christiansen's Modulus 686 amplifier does exactly this with six LM3886's. Paralleling TDA729x's is easier, though, as there's no need for current balancing output resistors with them.
Best regards!

 

[echelion]

Hi again!

Now im back to this project, not for the ps4la (i found the way to repair the original amp) but yes to turn autoamplified a couple of DAS Ds-8 speakers...

Im reasearching about the matter of change the phase of the TDA7293...Really i will need have to make a new board with a inver op amp? I cant do it simply inverting the wires of input?