rozumiem ze te 4 chinche (te co piszesz ¿e jak 1 z nich wpiêty jest , to jest OK) to s± chinche od sygna³u audio lec±ce od radia do wzmaka.

skoro piszczy kiedy pod³±czysz wiêcej ni¿ jeden, to mam przetestuj tak± rzecz:

pod³±cz jeden , a kolejny pod³±cz z jednej strony (no niech jest we wzmacniaczu normalnie wsadzony) a z drugiej pod³±cz tylko gor±cy przewód (tak aby masy siê NIE STYKA£Y)
We¿ kawa³ek druta i wsadz w chncha w radiu i dotknij potem bolca z kabla.

no i daj znaæ...

poczytaj trochê o szumach i piskach
http://www.crutchfield.com/S-ia4NsOL...ion_guide.html

Wychodzi ¿e u ciebie to:

Are you hearing engine noise?

Any amp installation can be prone to engine noise. You may hear a whining or clicking sound (its pitch will vary with engine speed). Since most noise problems come from a poor ground, always make sure your ground wire is connected firmly to bare metal in the event of a noise problem. You can also try isolating your amp from the chassis of your vehicle by mounting it on a board or using rubber grommets or feet; using a different brand of patch cables; or, only if all else fails, installing a noise suppressor . The tricky part is figuring out which step or steps to take. Please read the rest of this section and try some of the simple tests.

Noise in the patch cables

Noise can be picked up by the RCA patch cables connecting your components. To test this, detach the cables from your amp. (Note: A small number of amplifiers mute themselves when patch cables are removed. To defeat the automatic mute, insert one side (left or right) of a spare patch cable into the amp's left and right input jacks.) Turn on your system and engine. If the noise is gone, reconnect the cables to the amp, and disconnect them from your receiver. If you hear the noise, your patch cables are definitely picking it up. Try re-routing them, taking care to separate them from your power cable by at least 18 inches. Also, newer cars may have a cable that provides power to computers and lights in the rear of the vehicle — make sure that your patch cables aren't too close to this cable.

Standard patch cable Twisted pair patch cable

Inexpensive, standard patch cables (left) are more susceptible to noise
than premium, twisted pair designs (right).


You should also switch to higher-quality patch cables. The inexpensive RCA cables many people use to connect their components don't have the shielding or conductivity necessary to deflect noise in the metallic, highly-conductive automobile environment. Twisted pair RCA patch cables excel at rejecting noise generated by your vehicle. As a last resort, a ground loop isolator (like PAC's SNI-1) can be installed between the receiver's preamp outputs and your amp to minimize this problem.


Tropy s± dwa wg informacji:
s³aba masa dla wzmacniacza, podwójna masa dla wzmacniacza (kablem i przez obudowê) , s³abe kable po³o¿one niefortunni blisko jakiego¶ kabla gdzie alternator naturalnie szumi...

pozdr