Phoenix Gold Phorum

So i got up earlier to run to lowes and i started my car and as soon as i turn on the stereo i get a deep constant humm from my sub.

I pulled the rcas off the amp to pin point the source and it still has the same hum coming from the sub. So i know its not a signal issue.

Please dont tell me my ti600.2 is fried.

Heres my set up,

Pioneer premier deh-p880prs
Mids & highs straight to tld66
Sub out to ac epiccenter160
Epic to ti600.2 bridged to rsdc 12" @ 4 ohms
Mids & highs to ti500.4

Im rechecking wire routing on the ti600.2 now as we speak. Ill update

Any help please!

put the ti400.2 in to see if the noise is still here

K thanks mike ill let u know gonna take a few min as i have to remove the passenger seat, i have it mounted under there for usability of the back.

Mike i hooked the sub to L ch and then R channel, its only coming from left, it doesnt hum on the right channel at all

Hey is the power supply regulated on ti's? Cause if my lefy ch is shot then i gotta use my ti400.2 and ill run it at 2 ohm bridged to get more output

So looks like its something serious, took the amp out and removed it from the casing blew air thruout the board top and bottom, and inspected to see if a stray wire made contact anywhere and didnt see anything, and still the hum is there on the left channel....man im so pissed

What ohm load is your sub? I've run my rsdc 10s , dual2ohm, in parellel before, as when I've wired them that way, they've shown .9 on ohm meter, and they will rise a little~what I'm getting at is you could run ur sub at 1 ohm stereo, or keep,2 ohm bridged on the 400.2- hope ur 600.2 gets fixed soon- good luck

Its a dual 2 at 4ohms

Whats funny is i have 400.2 and seems like im getting more output from the 400.2 than the 600.2 and both are bridged

So if i use the right ch at 1ohm ill get more power to the sub, but im afraid ill get only right side music notes, but i have the hu set at mono for the lp output. Would i loose some notes doing what u said thedeal

Leave it wired as it is, now if u wanna do a lil test, or have fun, as i call it, run ur sub bridged to the rear of the 500.4, & see the results on ur output; ive done that before and been amazed!

Im using the front ch for mid bass/range and the rears for hp.

Thedeal, i did what u said. I loaded the right ch at 1ohm and it only plays half the volume as my ti400.2 bridged at 4ohms. I dont get it.

Im so frustrated. I wish i was more tech savy to diagnose the issue.......(face in hand plant!!!)

With the one side playing and the hum my guess might be an input issue inside the amp. Sounds silly but have you tried running the amp full range in case it's a crossover issue. You still have the crossover at the deck. Or just using different switch combos to see if it comes to life.

Have you checked the input section (the daughter board)? I have a feeling you may have some open resistors which can cause the hum...these resistors are tied to the ground signal. You might be able to spot them if they have burnt/toasty coat otherwise you will have to ohm them out.

Art, the hum happens even with out the rcas connected. I have the xover on the amp set to by. The hu is xovered at 100hz.
When i first heard the hum i disconnected the rcas too see if it a signal interference but that did help. Then i tried ach ch w/o the rcas and thats when i pin pointed it to the left ch of the amp. So the i took the amp out and tried my 400.2 and everything works great. So i removed the board from the chassis of the 600.2 and took a can of air to everything incase dust or a stray wire was causing a short. Then i rehooked it up and same issue as before. Then i tried what the deal said about 1ohm on the ch that works. That did do anything for the output of the amp. Ud think going from 4ohms to 1ohm would give me about 3x the output but it didnt.

I leave all the xovers on the amps set to by, cause i use my hu as a 3way oxver. Lp, mp, and hp.

Also this all happened one day when i went leave for work. The amp was installed and playing finr the evening before the next day. So its not like i was installing and it did that. Plus ive never driven any ch less than 4ohms till this evening when i tried what thedeal suggested.

Any other thoughts?

The amps have current sensing, so they limit output at low impedance. So you get same output at 1ohm as 2 ohms, but there should be a small gain from 4 to 2.


When designing the ZX amps we wanted a design that made its best power at normal loads. By that we mean 4 ohms bridged. Now we know that no matter what we say or how loud we say it people will still hook the amp up to lower impedances trying to get more power. So our number one goal is that the amp continue to operate at lower impedances. The only way to do that is to limit the power output of the amp when it's hooked up to lower impedances. But it really isn't that big of a deal. Here's why:

Wattage is equal to voltage times current. Running the amp at 2 ohms bridged means more output current. Current makes heat. We can't allow the amp to make more heat than the fan can deal with. The fan can deal with a bit more heat than what's generated from a 4 ohm bridged load. So there's some room for more power. Here's how we limit the power increase to what's manageable:

The ZX amps have a circuit that detects the amount of current going out of the speaker terminals. If the current is high enough AND last long enough (longer than 100 milliseconds), the circuit limits the amount of voltage that the power supply can produce. This in turn limits the power output of the amp. So continuous power output remains about the same with the power composed of more current and less voltage.

But there is a bright side to all this. Remember I said that the excess current demand had to last longer than 100ms. The dynamic peaks in most music last less than 20ms. So the circuit never has a chance to effect the power supply voltage for musical peaks. All this means that the amp IS allowed to make more power with musical peaks while continuous power remains about the same. You could say that the "headroom" of the amp is increased.

If you want to run the amp 2 ohms bridged, go for it. Just understand that it will run slightly hotter and will pull more current from your car to make those musical peaks (add more capacitors and use thick gauge power/ground wire). I wouldn't recommend running it 1 ohm bridged. The amp will shut down (red LED) if the output current gets too high (looks like a shorted speaker).

Thanks ricky! Ive read something like this before. But remember i didnt load the amp w 1ohm bridged, only one of the channels. Which is the same as 2ohm bridged.

Anyways ive given up on this 600.2 ive moved on to bigger and badder amps, like a 800.1 wink wink.

So u use to work for pg?

No, but i have a good friend.that did. He was a member here before vanishing, he helps me out when i get stuck.

Thanks for the help guys! I got a ti800.1 today from trickyricky to replace the ti600.2. I am sure itll be plenty for sub duty