Stereo Amp information???

JimIsbell · 02-15-2010, 09:26 PM

I have just received a Jensen A82 two channel 40 watt amplifier. I can find NO information on it on the Internet.

I need to know what the two leads labeled "source ground", black/white, (this is NOT power ground) and "auto sensor", blue/white, are used for. I am thinking the "source ground" is the ground side of the input signal though the inputs have two wires each labeled as "-" and "+". So maybe I should connect both negative sides and the "source ground" together. But the "auto sensor" I havent a clue.

Cobb · 02-16-2010, 12:27 AM

2 channel? You should have 6 connector leads. 2 for power 2 for left and 2 for right channel. The speaker and level connectors are DC, so sounds like they are using a common ground.

JimIsbell · 02-16-2010, 10:05 AM

I have 8 leads, 2 for left, 2 for right, two for power and a "Source Ground" and an "Auto sensor".

Then I also have two connector inputs, one pair of RCAs for "low level input" and a 4 pin PokHom for "high level input"

The two leads I dont understand are the "source ground" and the "auto sensor"

Everything is marked, BUT I dont understand the "meaning" of the two leads.

jh057 · 02-16-2010, 10:53 AM

Would "auto sensor" be the blue wire from the head unit? I'm thinking this is the "trigger" wire to tell the amp to turn on. I didn't see that listed in your description...

I'm wondering if "source ground" is some kind of noise isolation?

JimIsbell · 02-16-2010, 01:08 PM

The "auto sensor" lead is the blue/white lead in this amplifier. Maybe it needs to be either at ground or at 12VDC whatever the "logic" is, to make it go. When I connect it up I will see if that is a logic switch.

The other may be just a separate ground on the input if you have isolated grounds for the two chanels...which I dont have.

boelle · 02-16-2010, 05:20 PM

a common ground for both 12v and the signal would be somewhat rather stupid since that could lead to ground loops... and i dont think any maker of decent stereo would do that... but i could be wrong

JimIsbell · 02-16-2010, 05:51 PM

Ground loops are only a problem at RF frequencies. At audio its not a concern, the wavelength is so long that ground loops for all intents and purposes, dont exist. I have LOTS of audio equipment with common grounds for the audio and the power supply.

Cobb · 02-17-2010, 12:47 AM

So, this was a "free" amp?

Ok, so hook source ground to the ground of the car or ground of the power connector and auto sensor to either the remote of the radio or acc fuse so it comes on with the key.

The 4 pin is for speaker level inputs. You can use ither the rcas or that plug.

JimIsbell · 02-17-2010, 01:06 AM

Great, just what I was suspecting, but wanted some confirmation. Yes, its "free". A friend took it out of his sons car and was going to throw it away, I said..."Hey!!!, lets not do that!!!"

Cobb · 02-17-2010, 01:25 AM

My next suggestion would be to mail it to Mike D 2000 and have him video it after hooking it to his battery zapper and seeing what happens when he throws the switch.

Strange why it has a source ground for the remote. Most amps just have a remote lead that has a 12 volt signal when to turn on and lack of signal to turn off. Maybe it can run of a different voltage vs trigger by?