TDA2030: Max amplification ratio on 8Ohm load, +/- 12V ?

[T3STY]

A friend had many TDA2030 ICs so he decided to gift me some. I've checked the datasheet and I took a look at this amplifier, which seems to be a 30W (4Ω) / 15W(8Ω) Op-Amp. I looked at the testing circuit too but I don't really understand it, and I don't really like it. I've decided then to make my own circuit as a classic inverting Op-Amp circuit. I have proper heatsink and I'd like to get out the whole power of this IC.
What is the highest amplification ratio \[(\frac{Vo}{Vi})\] that this IC can take in a basic inverting circuit with 8Ω load and ±12V split supply?
Also, if I'd use 2 ICs in bridge configuration, would it really make the difference or I'd only get higher distortion?

p.s. for basic inverting circuit I mean this:
**broken link removed**

 

[audiospecialist]

Why do you need to go with Inverting type power amp .

Manufacturer spec recommends 30db to get best out of it.

Also, if I'd use 2 ICs in bridge configuration, would it really make the difference or I'd only get higher distortion?

You should get higher power, with same kind of topology as that for single chip you shouldn't be too much worried of any deviation for a bridge.

 

[T3STY]

30db? How much would that be for the resistor values?

Why do you need to go with Inverting type power amp

Just experimenting. Also, non-inverting amplifier cannot attenuate the volume because of \[Av=1+\frac{R2}{R1}\], that would always have an amplification ratio of 1 when volume is at minimum (R2=0, considering R2 as a variable resistor). It's not much but it creates some noise on the speakers at minimum volume.

 

[audiospecialist]

What do you mean by attenuation of volume here ?

For an inverting amp The Av=-R1/R2 .
this case can give you more trouble than good.
The Gain is dependent on series resistance so if there is any impedance issues from source, it will affect whole feedback loop.
Hope you realize Loudspeaker at the end termination of power amp is a dynamic load which is more inductive than resistive.

 

[T3STY]

For attenuation I mean reducing the volume up to 0, and it was meant in case I'd use a non-inverting configuration.

Which impedance issues from source should I expect? As source I may use the PC output or the cellphone output; would it affect that much the gain?
And yes, I know about loudspeakers actually being dynamic, but i'm ignoring this effect as there is not much I can do about it, I have only studied op-amps and their behaviour in basic standard circuits and my experimenting is based on that

 

[audiospecialist]

30db? How much would that be for the resistor values?

Just experimenting. Also, non-inverting amplifier cannot attenuate the volume because of \[Av=1+\frac{R2}{R1}\], that would always have an amplification ratio of 1 when volume is at minimum (R2=0, considering R2 as a variable resistor). It's not much but it creates some noise on the speakers at minimum volume.

I hope you are not over assuming things here.

Amplification of 1 cannot be called as amplification. It is a unity gain set up means no amplification.

Unlike a non inverting input, Inverting amp is dependent on input resistor. if you leave it open , the amp stays in infinity gain and .

neither you can ground it for zero output as you mentioned 0 volume,obviously it will invert the ground too.

By making fb resistor=0 you are again forcing it to unity gain nothing full attenuation rather your speaker output gets shorted to inverting input..

 

[T3STY]

Ok...so, what would you suggest to do? I just want to test the IC at its max power (as you said, 30db) to test output quality on two 120W 8Ω loudspeakers (1 IC per loudspeaker). My current amplifier is made in class B and makes a lot of noise during silent periods; it would be great if I could use the TDA2030 ICs for a good amplifier, but I want quality too.

p.s. yes, I know 15W on 120W loudspeakers is undersized, but hey, I live in a flat and 15W are enough in a room

 

[audiospecialist]

You can utilize the manufacturer application circuit from ST website and use it to your wish.
TDA2030 is a very good amp IC it has SNR of 98db+ which means good for CD music listening.

If you want Higher power you need to go with Tda7293 or discrete Amplifiers.

 

[T3STY]

OK, thank you for your time. I'll use the application circuit as you suggest.
just two last questions:
1) the circuit provides two diodes, one on pins 3 >| 4 (-Vs to Out) and one on pins 4 >| 5 (Out to +Vs). What are these there for?
2) What are the optional components intended for? (in the bridge circuit they are C3, C9, R4, R10)

 

[audiospecialist]

OK, thank you for your time. I'll use the application circuit as you suggest.
just two last questions:
1) the circuit provides two diodes, one on pins 3 >| 4 (-Vs to Out) and one on pins 4 >| 5 (Out to +Vs). What are these there for?
2) What are the optional components intended for? (in the bridge circuit they are C3, C9, R4, R10)

Pin 4 is output to speaker pin. those two diodes dampens the back EMF from loud speaker coils.

You lost me for the bridge circuit ,can you post the schematic to see which c3 r4 you are talking about?

 

[T3STY]

Sure! Here it is:
**broken link removed**

They're right under the Op-Amp, between pins 3 and 4.

 

[audiospecialist]

OK, thank you for your time. I'll use the application circuit as you suggest.
just two last questions:
1) the circuit provides two diodes, one on pins 3 >| 4 (-Vs to Out) and one on pins 4 >| 5 (Out to +Vs). What are these there for?
2) What are the optional components intended for? (in the bridge circuit they are C3, C9, R4, R10)

C3, C9, R4, R10 are basically bandwidth limiters to avoid HF oscillations ,you would need it in case the amp oscillate while in operation else you can ignore it.

 

[T3STY]

ok, got it! Thank you for your help!