serious line noise with MINOTAUR II

[theripster 0]

Problems with:



ZED Audio Minotaur II - this amp is creating some kind of feedback noise
to my entire system... at first, it was terrible. this crazy squealing
noise that just didn't stop, regardless if the car was actually running
of just had power to the stereo.



so i brought it back to the installer, and they put a ground noise
isolator (or something like that) in-line for the amp's RCAs. this
reduced the noise greatly, but then when i would turn on the car, the
sub would just start pounding for about a minute before it would stop.
this was regardless if there was any signal coming from the radio or
not.



then today i brought it back to the installer, and they grounded the
RCAs to the chassis, and it stopped the thumping upon start-up, but
there's still a lot of line noise. i asked them why it would be doing
that, and they said because it's probably made with cheap components... i
thought ZED was supposed to be top-notch? any ideas?

[Aaron Clinton 2,372]

It was not made with cheap components, the installer needs an update.  Do you have all 4 RCA inputs fed?  Was another amplifier tried?  Also, if the noise is being reduced when something is being placed inline before the Minotaur, doesn't that sound like it is something before the Minotaur causing the noise?

[ricksi30 923]

 Also, if the noise is being reduced when something is being placed inline before the Minotaur, doesn't that sound like it is something before the Minotaur causing the noise?

Agreed.

 

What head unit? A Pioneer?

[theripster 0]

yes, it is a Pioneer Avic Z150bh... brand new.

 

there's a few guys working at the shop... 2 of them say it's the zed amp, while another says that the RCAs in the Pioneer head unit must be bad... but both are brand new!

 

the thumping came back on the amp. i have no idea what it could be.

 

i think they might have ran the remote turn-on lead from the factory amp to this amp, because i did half the system at a time. first was the head unit and sub, and they wired the head unit to the factory amp, but i had them put in all RCAs for when i completed the second half (another amp plus components).

[ricksi30 923]

yes, it is a Pioneer Avic Z150bh... brand new.

 

there's a few guys working at the shop... 2 of them say it's the zed amp, while another says that the RCAs in the Pioneer head unit must be bad... but both are brand new!

 

the thumping came back on the amp. i have no idea what it could be.

 

i think they might have ran the remote turn-on lead from the factory amp to this amp, because i did half the system at a time. first was the head unit and sub, and they wired the head unit to the factory amp, but i had them put in all RCAs for when i completed the second half (another amp plus components).

Sounds like you need to find a new shop.

[///M5 2,833]

Anything in the chain could be bad, most likely the install. The amp itself is the last thing I'd expect.

[cloud77 28]

pico fuse

[Dangrebel 89]

You said it did it with no signal? Check ground connections just incase! I've had an amp do that before!

[Sencheezy 689]

I HIGHLY doubt it's the amp. Hell, the amp in my install STOPPED the whine where the other amps didn't.

[Aaron Clinton 2,372]

yes, it is a Pioneer Avic Z150bh... brand new.

 

there's a few guys working at the shop... 2 of them say it's the zed amp, while another says that the RCAs in the Pioneer head unit must be bad... but both are brand new!

 

the thumping came back on the amp. i have no idea what it could be.

 

i think they might have ran the remote turn-on lead from the factory amp to this amp, because i did half the system at a time. first was the head unit and sub, and they wired the head unit to the factory amp, but i had them put in all RCAs for when i completed the second half (another amp plus components).

Sounds like you need to find a new shop.

Bingo.

[95Honda 486]

With the amp turned on and NOTHING connected ANYWHERE on the signal input (I mean the RCA jacks are just sitting there with nothing connected) is there noise?

[theripster 0]

i will report back when i try some of the solutions mentioned... too hot right now here in south FL!!

[cloud77 28]

There is a noise trouble shooting guide on here somewhere.  Search forums.

[theripster 0]

I have a decent understanding of car stereo installation, as I have done
quite a few installs myself. So instead of feeling the wrath of the
installers, I decided to go through the system and attempt to isolate
the source of the noise...


Unfortunately, I found the problem... it is definitely the Zed amp!
After a while of playing around with everything, I was able to isolate
the noise.

When the Zed amp is disconnected, there is NO line
noise at all! For my components, I have a JL HD 600/4. While that is
plugged in, no matter what volume I play music on, there is no whine, no
interference, no hissing, NOTHING. When I start the car up with just
the JL amp plugged in, it starts up quietly. I honestly can't even tell
the car is on because everything is so quiet.


Then when I plug in the Zed amp, once the head unit powers on, I get
this insanely loud line noise. It sounds like an old-fashioned radio
that can't pick up a signal... extremely loud and annoying. This noise
occurs when the car is both on and off. Meaning, I can just power up the
head unit and the noise comes through, so it is definitely not
alternator whine. The noise level/frequency does not change with changes
in engine rpm or anything like that.


Then about 10 seconds after I power up the system with the zed amp
plugged in, the sub starts thumping for about a minute, and then stops.

[ricksi30 923]

Where did you buy the ZED? If it was new I'm sure they will warranty it.

[theripster 0]

the amp was purchased brand new from a reputable company, and they do offer a warranty...

 

so i tried a couple of different things:

 

-with NOTHING plugged in, there is absolutely no noise at all.

 

-with ONLY my JL amp plugged in for the surrounds, there is no noise either. i can turn up the volume from the head unit with no track playing, and no noise. i can play anything at any volume and there is no extra noise at all. i'm actually very impressed with how clean this amp is

 

-with ONLY the minotaur plugged in, i hear no noise, but that's because there's no signal going to the surround speakers.

 

>>> let me add this: i had the sub and minotaur installed PRIOR to upgrading my door speakers, and even when i was using my factory amp and factory surrounds, i had the same problem with the minotaur giving me line noise. so the JL amp is not the cause, as the problem was existant before the JL was introduced.

 

-with both the JL and the minotaur plugged in, i get a very, very loud whining noise. this noise occurs whether the car is fully on, or just the electronics are powered up. definitely not alternator whine

 

-with the ground loop noise isolator plugged in-line with the minotaur amp, the noise is greatly reduced. it is still definitely audible, but it is not the shrill, ear-piercing whine that i hear without the isolator. BUT when i have the isolator plugged in, the sub starts thumping very hard for about 2 minutes when i power up the system

 

i've read in a few places now that people have had bad luck with Zed amps and the line noise... i'm thinking about just exchanging it for a JL  HD750/1

 

i'm going to search for the noise troubleshooting right now... i'd rather find the cause of the problem and fix it as i don't want to go through the hassle of taking everything apart, sending it out, waiting for new pieces to come in, etc. i just want to be done with this mess!

Edited July 15, 2013 by theripster

[NB50 206]

http://www.soundsolutionsaudio.com/forum/topic/35027-noise-troubleshooting-guide/

[jcarter1885 995]

it sounds like it may be the sub rca jack or rcas themselves, do you have another sub amp to verify if its the zed amp before having to send it in.

[theripster 0]

it sounds like it may be the sub rca jack or rcas themselves, do you have another sub amp to verify if its the zed amp before having to send it in.

no extra amp....

 

i checked all the connections today. i literally took everything out, wires and all, speakers, head unit, everything... then put it all back in. same problem.

 

HOWEVER, the one and only thing i noticed was that the minotaur is grounded to the chassis rather than to the battery... is that OK?

[altoncustomtech 773]

it sounds like it may be the sub rca jack or rcas themselves, do you have another sub amp to verify if its the zed amp before having to send it in.

no extra amp....

 

i checked all the connections today. i literally took everything out, wires and all, speakers, head unit, everything... then put it all back in. same problem.

 

HOWEVER, the one and only thing i noticed was that the minotaur is grounded to the chassis rather than to the battery... is that OK?

 

Typically not a good idea.  That's how ground loops happen.  Each amp should be grounded to the same point and when that's not possible then the grounds should be made common by connecting them together with a wire.  

 

What kind of vehicle is it?  Some people were measuring nearly 100 ohms of resistance between any given point on the body/chassis and the ground post of the battery in GM vehicles awhile back.  Factory grounds tend to suck no matter the manufacturer and if a piece of equipment is grounded directly to a battery and another to the chassis there's great potential there for potential and that will cause a ground loop.

[smashedz28 110]

I've had sub out rcas on my head unit crap out before. I may have missed if you ruled that out or not.

[Julian 641]

Sounds like a ground issue, choose a better ground to see if that'll change it up

[jarfunkz 0]

You have another amp, your jl amp.  I say plug that into the sub portion and see what happens.  You have done a lot, you just haven't isolated the subwoofer: deck to rca's as being the culprit.

[gsWes 4]

Had the same issue with a minotaur 2! Sent back once still broke! Sent back again and got a refund.. I to thought it was my error in wiring but my new sundown 1200 is workin like a champ!! I purchased my zed from zed and paid shipping to return a brandnew broke amp twice!!! Guess it was a 60 dollar donation to " the man"..

[garychurch84 127]

I had this problem too.fixed it pretty easy.ran another ground to my head unit