help for an amplifier circuit

[erik42788088]

Hello everyone, for a project I would like to measure the differences obtained from two different classes of amplifiers. Specifically I wanted to compare the tda7297 and tpa3122.
In this regard it would be ideal to create a circuit as similar as possible between the two, così le differenze si ridurranno ai finali stessi.
Unfortunately I don't have the skills to make it, can someone help me?

 

[Killingbeans]

The only similarity you can get with those two, is to make sure they both have the same gain. The TDA7297 needs nearly no external components at all and has a fixed gain of 32dB. The TPA3122 also needs almost nothing other than its output filter (because it's class-D) and takes a binary value on two of its input pins to set the gain as either 20, 26, 32 or 36dB.

If you really want to compare the two, any decent PCB you can find on eBay should be sufficient.

 

[erik42788088]

Spiego cosa vorrei fare. Per una tesi voglio portare l'amplificatore audio, le sue parti e le classi di funzionamento. Poi voglio misurare le differenze tra una classe AB e una classe D, costruendo un unico amplificatore dove posso cambiare i due amplificatori.
Rendendo stabili l'alimentazione, l'ingresso e l'uscita, le differenze rilevate ricadrebbero sulla classe operativa

Questa sarebbe l'idea, ma a questo punto non so se sia fattibile

 

[sergeauckland]

Yes

Spiego cosa vorrei fare. Per una tesi voglio portare l'amplificatore audio, le sue parti e le classi di funzionamento. Poi voglio misurare le differenze tra una classe AB e una classe D, costruendo un unico amplificatore dove posso cambiare i due amplificatori.
Rendendo stabili l'alimentazione, l'ingresso e l'uscita, le differenze rilevate ricadrebbero sulla classe operativa

Questa sarebbe l'idea, ma a questo punto non so se sia fattibile

Yes, perfectly possible. In effects you're creating the conditions for a blind test between two amplifiers of equal gain, just of different classes. You also need to ensure that neither amplifier is clipping, and both amplifiers are driving a load within their capabilities.

S.

 

[erik42788088]

so if I buy the two pcbs and put them on the same profit there is no need to build them?

For the choice of comparison do you agree or do I have to change?
I already have a tda7297 available so I was looking for a class D, I was undecided between tpa3110 and tpa3122, what do you recommend? do you have alternatives?

 

[sergeauckland]

so if I buy the two pcbs and put them on the same profit there is no need to build them?

For the choice of comparison do you agree or do I have to change?
I already have a tda7297 available so I was looking for a class D, I was undecided between tpa3110 and tpa3122, what do you recommend? do you have alternatives?

Yes, if you set the two boards to the same gain (guadagno in English is gain when talking about electronics, profit when talking about money), then as long as you make sure neither board is clipping, you can compare them directly.

S

 

[erik42788088]

Yes, if you set the two boards to the same gain (guadagno in English is gain when talking about electronics, profit when talking about money), then as long as you make sure neither board is clipping, you can compare them directly.

S

sorry if I translated wrong, I meant gain.
for the choice of class D, what do you tell me?

 

[sergeauckland]

sorry if I translated wrong, I meant gain.
for the choice of class D, what do you tell me?

No problem about translation. I'm Italian by origin, but born in the UK. My mother had the good sense to bring me up speaking Italian. My written Italian is now pretty poor from lack of practice.

Regarding the amplifiers, the 3110 has a bridge tied load configuration, the 3122 is conventional single ended and so easier to use in comparison with a conventional class AB amplifier. Both amplifiers are fairly low power, so when comparing them to any other amplifier you need to use sensitive loudspeakers and make sure they are not clipping, using an oscilloscope or build a clipping indicator.

S

 

[erik42788088]

No problem about translation. I'm Italian by origin, but born in the UK. My mother had the good sense to bring me up speaking Italian. My written Italian is now pretty poor from lack of practice.

Regarding the amplifiers, the 3110 has a bridge tied load configuration, the 3122 is conventional single ended and so easier to use in comparison with a conventional class AB amplifier. Both amplifiers are fairly low power, so when comparing them to any other amplifier you need to use sensitive loudspeakers and make sure they are not clipping, using an oscilloscope or build a clipping indicator.

S

fantastic, I'm happy to have found a compatriot.

I asked the question about class D because, in Italy, the tpa3110 is easy to find, unlike the 3122, but I don't know if the discussion on gain is also valid for him.
yes i will use an oscilloscope to avoid clipping. As speakers I have a pair of Klipsch RP-5000F

 

[sergeauckland]

fantastic, I'm happy to have found a compatriot.

I asked the question about class D because, in Italy, the tpa3110 is easy to find, unlike the 3122, but I don't know if the discussion on gain is also valid for him.
yes i will use an oscilloscope to avoid clipping. As speakers I have a pair of Klipsch RP-5000F

You can easily adjust gain with an external potentiometer on whichever amplifier has more gain. The actual gain level won't make any difference to the sound, but you must match gains accurately, ideally to 0.1dB, to make comparisons.

S