Poor sound in both K8060

Good Morning.
I bought two kits K8060 for mounting on active speakers and after mounting and adjusting both the bias correctly (10mV) have the same problem in both units.
The fact is that when I connect an audio source (in this case I tested with my mobile phone and later with an iPod) and the sound you hear in the speaker amplifier is not poor in terms of power.
It is poor in quality. It sounds fatal.
It reminds me of the old tuners.
The sound quality is not any, as would be expected by the source that generates the input signal (Ipod or phone).
To state that use as sound samples songs with headphones perfect sound and have a correct equalization, logically according to my tastes.
I checked the connections, the temperature of transistors and everything is correct.
What can be wrong?
The input signal I’m using, not is it valid?
A one preamp is needed?
I await your response.
Thank you very much for your attention.

Difficult to solve from a distance.
Anyway, what power supply do you use?
Can you provide links to pictures of your assembly?
Did you try with a decent line level source such as e.g. a CD player?

Good morning.
First of all thank the quick response.
Regarding your questions to try to help me, indicate that the transformers that I bought for both amplifiers is the following link: http://es.rs-online.com/web/p/transformadores-toroidales/2238049/?origin=%20PSF_430727%20|%20alt.
We’ve double output to 25 volts and 120 VA (actually delivering 27 volts in my voltmeter without load).
This afternoon I’ll go to the store where I bought the speakers because I believe that the problem is not of amplifiers, is the problem of the speakers.
And I say this because the speakers are 175W (8 ohms) [color=#BF0000]RMS[/color] (350W max.) and I think the problem I mentioned is low quality because the amplifier can not “move” freely those speakers.
I go to the store with one of the two amps and we will try other less powerful speakers.
In the event that they fail to give me solution to the problem by changing the speakers I will contact with you, sending photos and all your needed to give a good end to my project.
Finally, does the headphone output of an ipod, telephone or PC is not enough to excite the entrance to the amp?
Thanks.