amp connections

[goodall]

my friend installed a alpine amp and sub to boot his car month so back

he is using the oem head which didnt have and rca outputs and has patched a female rca cable onto one the rear speaker cables, is this ok or will do damage tot he amp, it seems be flashing a protection led to indicator rca ground float, anyone know about this as he asked me if i knew but said no, but i though i may well look into it abit by asking on here

[nip]

It will blow the speaker channels in the stereo, you need a headunit with rca`s

[Acidburn]

Only amps afaik that you can do this with is the one's that offer input via normal speaker connections.

[Fat Audi 80]

Disconnect it right away. The voltages are way too high in that line unless your amp accepts "speaker level" inputs... (It doesn't sound like it)

A HU with RCA outputs will not be very expensive. Get one and then to it properly.

Cheers,

Steve

[Greg_S]

In the meantime you could build yourself a little potential divider resistor circuit to bring the voltage down to a suitable level, or if you dont want to do that or get a new head unit get something along these lines http://www.icebuyer.co.uk/speaker-to...r-p-12019.html

[goodall]

oh right well i dont think has speaker level input

as for a potential divider sounds like fair idea
if i was to either tell him get two resistors or made it for him, id need know the speaker line level (14.4 max i guess) but more importantly the rca max voltage for full range.
using 1/4w resistors the resistance across the whole divider cant be any less than 800ohm which i guess will stare the speaker off less than 1/200 of its power

oh im wondering what damage may already be done, ah well at least aint my gear

[Sonic]

oh im wondering what damage may already be done, ah well at least aint my gear

Hopefully none because the amp is clever enough to go into protection mode!

[FITZY]

You used to be able to buy something called a line level convertor, speaker wires in - clever little box - rca's out. Wouldn't be suprised if Maplins don't still do something like this.

[Jamo]

What? Bleeding cowboy!

http://caraudiosecurity.com/shop/product/products_id/3794.html

That's what he needs

[FITZY]

That's the sort of thing I was talking about, they've changed a bit since my day, though