Amp producing DC current?

Subject: Amp producing DC current? Thu Jul 24, 2008 9:28 am

So how would I tell if my amp is producing DC instead of AC or just producing bursts of DC?

Through a convo with rusty and the fact that I turned the coils to ash and snapped both leads in the woofer I sent to him that was one of the suggestions he brought up.
_________________

Team Bad Company
Team DC AUDIO
Team POWERMASTER

Unofficial DC AUDIO Testing Dept. - "Blowing Subs so you don't have to!"
DC Audio Dealer - Louisiana

Subject: Re: Amp producing DC current? Thu Jul 24, 2008 9:43 am

If it was producing DC you would have heard just a steady burp kinda sound coming from the subs or through a test speaker if you hook it up to a bench and then a test speaker is should sound like your at a comp burping in the lanes if its DC output....I think
_________________
JIMBO

TEAM DB DRIVE
TEAM REVOLUTION
TEAM BROKEN SILENCE.
TEAM SMALL PENIS(but can lick my eyebrows)
DARVILLE MOLESTER AT LARGE.

Subject: Re: Amp producing DC current? Thu Jul 24, 2008 9:54 am

I'm sure rusty doens't mind quoting a few lines of some PMs but here is how this whole ordeal came about:

"I had a question also about your set up, did the woofer smoke in your ride or did you plug it into the wall? I only ask because the leads on both coils were burnt in half and the coil was just short of ash, in 5 years of building subs ive never seen a coil that charred. dosent matter to me either way i said kill em =] just wondering. if you werent trying to smoke them and they got like that there not going to last very long."

"Do you have a voltage meter? Maybe that yellow top isent providing enough reserve? Burnt coils and lead wire is caused by to much heat, heat is eith to much power for a woofer, really bad clipped signal (too much voltage input,too high of gains for amount of voltage imput/ over Eq'ed) or a amp producing DC current, DC will cook a woofer faster than anything but Ive reconed woofers after Super Street Deathmatches that were better looking than yours =] Theres something going on there, but without haveing the car in my hands theres no way for me to help. I will send a pic of your coil, you will laugh at it =]"
_________________

Team Bad Company
Team DC AUDIO
Team POWERMASTER

Unofficial DC AUDIO Testing Dept. - "Blowing Subs so you don't have to!"
DC Audio Dealer - Louisiana

Advanced Contributor Joined : 26 Jun 2007 Posts : 359

I really hate to break this to you and I am sure there is going to be a lot of people that don't believe me, but that is okay. It will just show how much people really know about amps.

It is IMPOSSIBLE for a car audio amplifier to product a true "DC" signal. Rather then explain it the science behind that let me just put it like this.

A speaker requires an AC signal to allow a cone to travel out then and backwards. If there was a DC signal the cones would simply push out or backwards and stay there. Even in a fully clipped signal is still AC.

There is a demonstration I can do to prove there is no DC that exists. All that is needed is a light bulb, large capacitor, and an amplifier with signal to it.

Clipping, and over powering take out subs.
_________________
Gabe Sanchez

Pioneer Electronics
National Trainer

Team GForce
Team dB Driven

Subject: Re: Amp producing DC current? Thu Jul 24, 2008 11:04 am

DC out(clipped signal) of the amp would appear as sub stuck OUT or IN.
Clipped signals look like DC(constant voltage) on the ends of the curve, square.
more clip=more heat.

there's a guy local to me that burnt his leads on one of his level 5 at heatwave, hhmmm.
_________________
Doug Blohm
Team Aces

We are just louder, deal with it!

Subject: Re: Amp producing DC current? Thu Jul 24, 2008 11:10 am

yea andrew, he told me about that. I don't have voltage issues, so idk what would be causeing this but I blew out 2 l7s then a month later blew out two dc 18s. I'll have to recheck my wiring and settings i guess
_________________

Team Bad Company
Team DC AUDIO
Team POWERMASTER

Unofficial DC AUDIO Testing Dept. - "Blowing Subs so you don't have to!"
DC Audio Dealer - Louisiana

Subject: Re: Amp producing DC current? Thu Jul 24, 2008 11:13 am

Yep clipping the signal is the worst thing for a woofer. This is why most woofers fail. Usually though the leads will burn through or the coil will go not both. What you do to it TUB???? So i guess when it started to smell you just kept it wide open??LOL Wish I could have been there.
_________________
Bret Arceneaux
Team S.P.E.A.D
2003 Crew Cab F150
4 9515F's
2 DD M3's
Mod 1001-2000
157.3 @ 47HZ
SB4 156.0(young jeezy 44hz)

Subject: Re: Amp producing DC current? Thu Jul 24, 2008 11:26 am

Subject: Re: Amp producing DC current? Thu Jul 24, 2008 11:46 am

Should have said he was a fag or liked cock or something while he was logged in gosh..... HEHE Around my shop you stay logged in hehe you get alot of crazy posts...LOL You Wont Do It.....HEHE
_________________
JIMBO

TEAM DB DRIVE
TEAM REVOLUTION
TEAM BROKEN SILENCE.
TEAM SMALL PENIS(but can lick my eyebrows)
DARVILLE MOLESTER AT LARGE.

Pro Contributor Age : 36 Joined : 25 Jun 2007 Posts : 739

Jimbo, Y waste my keystrokes saying stuff about him that everyone already knows.
_________________
Beelo

Stereo West Auto Toys
2006-7 Mobile Electronics Magazine Retailer of the Year
Omaha, NE

S.W.A.T. Team
Street Beatz
TEAM PIE Quality Control Division: Official Taste Tester

Subject: Re: Amp producing DC current? Thu Jul 24, 2008 12:07 pm

Hey, You weren't supposed to say anything.
_________________
Stereo West Auto Toys
74th And Dodge, Omaha NE

S.W.A.T. Team
Street Beatz
P.S.S (PIE SECRET SERVICE)

FAT MAN IN A LITTLE CAR!!!

Chris Burroughs
2007 Pro Stock 601-1800 4th Place 159.9

Subject: Re: Amp producing DC current? Thu Jul 24, 2008 12:34 pm

Subject: Re: Amp producing DC current? Thu Jul 24, 2008 1:29 pm

if you look at dc on an o scope there will be no wave at all pretty much a flat line my guess is you clipped the living Dung Pile out of them lol i gues i couldsee how enough dc voltage and current would burn a coil up pretty bad as there would be no excursion to cool the coil with the sub sitting static with power to it i would think it would take quite a bit of time or power to cause a sub to fail that badly using dc .
_________________
TEAM DB DRIVEN
Team Revolution
thanks to all my teammates for everything!
SUPAFLY LIVIN DOUBLEWIDE

Subject: Re: Amp producing DC current? Thu Jul 24, 2008 1:32 pm

I don't know what's up, when I pull this stuff out and put it in the new truck I'll be able to check everything.

I had the 2 L7 15s running on that amp for a year with no problem. Right near the 1 year mark I had one of them LOCK up. I mean you couldn't move the cone at all, the other just blew.

The DCs blew also shorlty thereafter.
_________________

Team Bad Company
Team DC AUDIO
Team POWERMASTER

Unofficial DC AUDIO Testing Dept. - "Blowing Subs so you don't have to!"
DC Audio Dealer - Louisiana

Advanced Contributor Joined : 26 Jun 2007 Posts : 359

There is also pulsed DC. That is a signal that starts at 0 volts and has its' sustained peak for a brief moment prior to returning to 0 volts once again. There is never negative voltage.

There are applications that require this type of signal. It can also be found on cheap power converters. It can also be smoothed out with enough capacitance.
_________________
Gabe Sanchez

Pioneer Electronics
National Trainer

Team GForce
Team dB Driven