KEVIN G.

Hooked up an old amp that a friend gave me to my Pioneer 12"...
I took my time and made sure all my wires were clean and no frayed ends. used connectors... Bridged the amp, turned everything down to begin with, and moved from there...
Powered up, and raised the output and level, It immediately went into protection, (light lit red), and had zero output.
I double checked my connections...everything seems to be right. I then lowered all the gain and level, and slowly raised each. It got some bass, but cut out fairly early.
I then un-bridged,(hooked up one side only) and started again. I was able to raise the output more this time, but it still went to protection.
Anyone know off hand what the prob could be??
Jim, you out there??
I know it's not high-end stuff, but I can't think what could be causing this.
Pioneer HU, 50w x4
Pioneer SVC 12" 4ohm
Jensen XH275 300w 4ohm

TomP

Might just be because it's a Jensen amp. I played with two amps that did that; my old Pyramid Pro amp (hey, it was 1994 and I was young and broke) and a friend's Crunch amp. On both of those, if the power was turned up past a certain point- even tho there was no distortion and plenty of **** left to turn- "click" a little light would come on saying "protection".

I'm still not sure what those amps were protecting.

KEVIN G.

I was kinda hopin' that wasn't the case... I mean, I know they're cheappies but, there's a market for them y'know, otherwise they wouldn't have been around this long.
any way to bypass the protection circuit to see if it even works ?
Hell, even when I drop below the overage...and I crank the HU, it dives into protection again!!!!!!!!!!!!!!

pudgedawg007

iTrader: (1)

try it without bridging the amp my friend use to have a jensen that would blown fuses whenever he had it bridged but unbridged it worked fine

KEVIN G.

pudgedawg007

iTrader: (1)

what do you have the levels at on the amp leave them at half way if you don't already and try it

NEEDAZ

Bad amp or maybe a bad speaker. Check the resistance of the speaker with a DMM, make sure it’s 4 ohms. Also, check the outputs of the amps for DC. Just set the meter to DC volts and see what you got. ANY DC on the outputs is bad.
To answer the question, there are three things that will set THAT amp into protection.
1 Over current in the output stage.
2 thermal protection if the amp gets to hot.
3 DC offset or a bias problem.
The last one sound like your problem.

Dan8289gta

Check your ground wire if its not very secure amps will do that sometimes, when your ground is disconnected and the positive and remote both have power the protection light will come on,

KEVIN G.

Well the speaker is presenting a .8 ohm load... Not very healthy for a two ohm stable amp...
Caveat Emptor I guess, bought it on e-bay, shoulda known. Wish I woulda known how to check when I received it, I had a seven day window...

NEEDAZ

0.8 ohm load, that'll throw it into over current in short order.

ScrapMaker

the speaker is only single voice-coil? if its dual, you can make it into a 2/4ohm setup, right?

KEVIN G.

ScrapMaker

oof... right through the heart... I guess your voice coil is damaged then?

KEVIN G.

Well, I hooked up a JL Audio 10/WO tonight, and it bumped pretty good out of one side, as soon as I bridged the amp , though, off to Protect mode again....
I dunno WTF, but its really pissin' me off!
My buddy walked across the shop with his 12 W3, that is bridged at the speaker...I added that to the other channel, and could push it as hard as I wanted... As soon as I unhooked the 10 and tried to bridge...Bang!!! Into protect...

ScrapMaker

check the wiring... maybe its going into protect mode because the voice coils are wired wrong...

KEVIN G.

I kinda doubt it... Three different speakers... Two of which I know work as my buddy just pulled them outta his Avalanche.

NEEDAZ

Sound to me like the amp is bad. Probably one of the channels has the bias a little off. Seen it before with Jensen.