K8060 low frequency response


I have constructed a K8060 Amp kit and when i measured the output of the Amp using my TrueRta Analyzer
i found out that as i turn the pot clockwise the low frequency response is decreased.

For example at low output the frequency response at 10Hz is (+1dB) at medium output is almost flat (0dB)
and at high output is(-2.5dB).

Is this a normal behavior or something went wrong;

I have a printscreen that depicts the frequency response of the Amp as discussed above
but as iam new to this forum i do not know how to send an attached picture.
A little advise is required please.


Looks quite normal for a simple circuit such as the K8060.
All depends on output power, load, etc…
-2.5dB is still a bit better than -3dB which is used to determine freq. response.

-2.5dB is not that bad…

The strange thing is that the low frequency changes as you turn the pot from +1dB to -2.5dB.

How can i keep the low frequency roll-off stable as i turn the volume pot;

Also please let me know how could i post pictures.


You cannot post pictures, you have to provide links to pictures.

and how can i provide links to pictures;

how can i avoid the fluctuation of the low frequency roll-off regardless of the amp output;

To add pictures, you need to host your pictures somewhere and provide links to those pictures.

Sorry, at this time we do not know why you notice this difference. Most likely, it is a property of this low-cost and simple circuit.

I notice the difference again and again just because your answer is not clear enough and
iam not sure that you have understood the problem.

The -2.5dB at 10Hz is not a problem at all .

The problem is that is not always at -2.5dB level.
Starts at +1dB at low volume and goes to -2.5dB at high volume.

At your answers you only mention the -2.5dB point not the +1dB so iam not sure you have understood well the problem.

If it is normal at low output to have a gain of +1dB at 10Hz and at high output -2.5dB then there is no problem and i can accept it.
It is a matter of how you apply the answer.

The same apply for the link to pictures issue .
I thought that you have a solution for your users but it seems that is to responsibility of the users to provide that link.

I do not want by any means to waste your time or to cause any inconvinience to your or to Velleman.

I hope iam clear now


Yes, it is the responsability of the user to provide the link.
Once again, sorry, at this time we do not know what might be at the cause of this behaviour and we do not have the means to test or simulate it.
Most likely, this behaviour is related to the fact that this circuit is very basic.