small solid state amplifier for high fidelity receiver needed

[neazoi]

Hello I need to replace the low power amplifier shown in this photo with another BJT one of about the same power. High dynamic range and fidelity is desired. Class-A not mandatory but desired.

I have another opamp NE5534 in the input, instead of the one shown in the picture, so I do not know where to connect the feedback. A feedback-less amplifier would be ideal.

Any designs to propose?

[neazoi]

I have found these...
How to build Pure Class-A Headphone Amplifier Schematic - circuit diagram
How to build 5 Watt Class-A Audio Amplifier Circuit - circuit diagram

[lineup]

I have built the clone of your amplifier around one NE5534.

The output stage I run in Class AB with like 25 mA idle in output transistors.
But this can be adjusted with R5 potentiometer, upto like 500mA for Class A.

In front of the circuit in diagram, you may want to add a Volume-pot.

As you can see the max output is like 1.5 Watt into 8 Ohm.
Should be almost the double with 4 Ohm speakers.
This will give loud sounds.
It does not take more than a few watts to fill a normal rook with music.

[lineup]

Originally Posted by neazoi

How to build 5 Watt Class-A Audio Amplifier Circuit - circuit diagram

That one looks as a good and simple project.
5 pure Class a Watt is a good thing.
Maybe you should go for that one.

[neazoi]

Originally Posted by lineup

That one looks as a good and simple project.
5 pure Class a Watt is a good thing.
Maybe you should go for that one.

I am very susceptible about this one. These are small transistors to get an output of 5W. Also it seems to me very simple, just two stages to get 5w output?

[Tekko]

I wouldent touch either of those super simple circuits, their simply not worth building. I'd atleast go with a P3B for class A or similar circuit, but preferably something more like those im building.

[wahab]

Thie integrated amp is already enough...

You should first extend its lower end bandwith wich is drasticaly
limited by the output capacitor C31 wich is only 68uF..
Depending of the speaker s impedance, increase it to 1000uF
at least for 8 ohm and 2200uF for a 4 ohm speaker..

Otherwise, you wont get more power whatever the amp
if the power supply is to stay at 12V.

[neazoi]

Originally Posted by wahab

Thie integrated amp is already enough...

You should first extend its lower end bandwith wich is drasticaly
limited by the output capacitor C31 wich is only 68uF..
Depending of the speaker s impedance, increase it to 1000uF
at least for 8 ohm and 2200uF for a 4 ohm speaker..

Otherwise, you wont get more power whatever the amp
if the power supply is to stay at 12V.

This is a tested schematic. I do not need more power out of it. The only problem is the feedback loop, which I do not know where and how to connect it, to the op-amp that I am using.

The opamp I am using is this one attached. And I want to match it with the first schematic I have posted, but I do not know where and how to connect the feedback loop

[neazoi]

a better scan of the opamp

[wahab]

If there s no integrated amp, you can just add a simple IC based one.
A TDA2040 will provide very good quality in respect of the complexity.



Edit : the 2uf capacitor in serial with the 4.7K resistor should be increased
to about 22 to 47 uF to extend the low frequency response..