In comtemplating a HU upgrade, I see in some of the specs., Alpine and Kenwood especially, have the option of turning off the built in amp, to improve the signal to the preamp outputs. But there is not detailed information about how much of a difference this makes. If you look at the spec sheet or consult the manual, (Cruthfield is great for this), this is no measurable information. They just say that it will improve the signal to the preamp outputs.

Has anyone investigated this feature more fully? Or done an A/B comparison?

Any HU I will purchase will not use the built in amp power.


I am dissapointed that there are few if any headunits that are pre-amp only. I found a Clarion, but it is selling for more than $1,000.

Thanks,
Chris

 

I never really looked into this till I read this thread. My Alpine does have that feature (CDA-9853) and so I will give it a whirl next time I drive it. I don't know if I will notice a difference since I've only had the new setup in my car for less than two weeks. But if nothing else it should keep the heat down.

 

It won't matter if you run the speakers and sub to the amp. If you didn't run the wires to the amp it will matter. I am taking about running it with a new speaker wire to the amp.

 

Huh?

 

good for keeping temps down inside the HU

 

If you have an amp and no speaker directly connected to the HU shut it off... if your running speakers from the HU leave it on.

 

Power IC Off: When an external amplifier is connected and the built-in amplifier is not used, removing power from the built-in amplifier will improve the sound quality.

From Alpine Manual

Does anyone know what this sound quality difference is? Is it measurable?

 

I doubt you could hear the difference. But I'm sure with a computer and a mic you could pick up the difference.

 

I have it off on mine, and think it sounds a bit better.

 

So it is really a marketing gimick. Thanks for the info.

There are not many HU that come with 4 or 5 volt outputs. The higher end Alpines, Kenwoods and JVC are that way.

Does anyone know much about BOSS? I think they used to be made by the same company that makes JVC, but now I don't know. They manufacture headunits which come with 5 volts output as standard and are quite affordable.

In the same vein, what about Eclipse? Crutchfield is now stocking them and most of their HU are 5 volts too.

Chris