bad ground

Brad06 · Post by **Brad06** » Sat Jul 28, 2007 6:34 pm

Is it possible for a bad ground on your amp to cause a sub to get hot? Thanks

brenzbmr@sb · Post by **brenzbmr@sb** » Sun Jul 29, 2007 12:11 am

no i dont beleive it would but it would cause havoc on your power supply

a hot speaker is caused by massive amouts of pwer or a poor

design in heat transfer

or a good one if you think about it.

sub7 · Post by **sub7** » Sun Jul 29, 2007 7:37 am

Would a bad ground not induce voltage drop hence making the amp work harder so in theroy get warmer ?? correct me if im wrong

1moreamp · Post by **1moreamp** » Sun Jul 29, 2007 7:57 am

Yeah a bad ground can blow your amp but it won't cause any issues at the speaker level except power loss to the driver and excessive heat build up in the AMP, not the speaker. I have seen it blow power supplies out in amps.

And this is what i do for a living, repair amps

brenzbmr@sb · Post by **brenzbmr@sb** » Sun Jul 29, 2007 11:09 am

no it wouldnt cause the sub to get harder,

if you amp works harder its gonna gererate heat. not the sub

vin78 · Post by **vin78** » Sun Jul 29, 2007 11:18 am

I've seen bad grounds melt ground wires, not subs.

Brad06 · Post by **Brad06** » Sun Jul 29, 2007 11:34 am

Ok, i understand bad grounds can blow amps up, but ive NEVER smelled anything before. I actually turned my amp down to a little less than 3/4 on the gain, and turned my HU from -3 to 0. Its a rockford fosgate p8002 amp, 2 15" 4ohm dvc subs in a vented box.

Post by **AVICJR** » Sun Jul 29, 2007 11:38 am

Is it possible that you were clipping the sub with the gain all the way up? If your gain is too high then it is possible to overheat/blow the woofer/voice coil.

Brad06 · Post by **Brad06** » Sun Jul 29, 2007 1:36 pm

My subs worked fine, no clipping at all (to the human ears) until i installed my rockford fosgate 2002 amp for my highs. after installing the amp that runs my highs, i turned my gain down on the 8002 (subwoofer amp). this is when i started to smell the dreaded smell!

brenzbmr@sb · Post by **brenzbmr@sb** » Sun Jul 29, 2007 4:26 pm

let me ask you this.
areyou playing it louder now then before(subs)

gains dont mean anything in this situation

ou added an amp to your highs and now you turned down your gain for your sub amp which leads me to believe that you are playing your sub harder then you did before because

a. you have louder highs
b. you turned your gains down and have to crank sub level or volume up more to make it seem as it did before.

because they dont sound or hit as loud as they did before.

i could be shooting in the dark but thats what it kinda sounds like to me

so now your working the subs harder possible clipping your amp which will make the amp generate more pwer(a clipping amp will make more power, something in the nature of the square wave and the pwer suppy, then in non clip mode) which could be heating up your coils to the point where the glue is starting to smell or
the coil is burning.

1moreamp · Post by **1moreamp** » Sun Jul 29, 2007 7:53 pm

How are his subs wired to the amp ?? What load and connection setup ? Have you checked the speaker terminals for DC voltage output with no signal going to the RCAs, and the amp just turned on without speakers connected either ??

This RF amp will put out DC voltage on the speaker terminals if its damaged and that will smoke your voice coils, and so will clipping the amp. So there are several possibilities, and if your not familiar with the things we told you about then you might need a good sound person to check all these things for you, and soon before you need to buy new speakers, and maybe a new amp

Brad06 · Post by **Brad06** » Mon Jul 30, 2007 4:42 am

subs are bridged to the amp and the subs are wired Voice coils wired in series, speakers wired in parallel, resuulting in a 4 ohm load. i believe 4ohm is the best i can get with my setup? i will check my amp for dc output when i get off work tonight, and post my results on the forum. Thanks for the advice fellas, im glad i finally found an IMFORMATIVE forum!

1moreamp · Post by **1moreamp** » Mon Jul 30, 2007 7:28 am

we will all be here. and I know these are glad to help when they can

Brad06 · Post by **Brad06** » Mon Jul 30, 2007 6:10 pm

1moreamp wrote:How are his subs wired to the amp ?? What load and connection setup ? Have you checked the speaker terminals for DC voltage output with no signal going to the RCAs, and the amp just turned on without speakers connected either ??

This RF amp will put out DC voltage on the speaker terminals if its damaged and that will smoke your voice coils, and so will clipping the amp. So there are several possibilities, and if your not familiar with the things we told you about then you might need a good sound person to check all these things for you, and soon before you need to buy new speakers, and maybe a new amp

when you say "No signal going to the rca's, do you mean disconnect the RCA's from my amp?

Post by **AVICJR** » Mon Jul 30, 2007 6:16 pm

Brad06 wrote:
1moreamp wrote:How are his subs wired to the amp ?? What load and connection setup ? Have you checked the speaker terminals for DC voltage output with no signal going to the RCAs, and the amp just turned on without speakers connected either ??

This RF amp will put out DC voltage on the speaker terminals if its damaged and that will smoke your voice coils, and so will clipping the amp. So there are several possibilities, and if your not familiar with the things we told you about then you might need a good sound person to check all these things for you, and soon before you need to buy new speakers, and maybe a new amp

when you say "No signal going to the rca's, do you mean disconnect the RCA's from my amp?

Correct.

Post by **fuzzysnuggleduck** » Mon Jul 30, 2007 6:21 pm

Brad06 wrote:
1moreamp wrote:How are his subs wired to the amp ?? What load and connection setup ? Have you checked the speaker terminals for DC voltage output with no signal going to the RCAs, and the amp just turned on without speakers connected either ??

This RF amp will put out DC voltage on the speaker terminals if its damaged and that will smoke your voice coils, and so will clipping the amp. So there are several possibilities, and if your not familiar with the things we told you about then you might need a good sound person to check all these things for you, and soon before you need to buy new speakers, and maybe a new amp

when you say "No signal going to the rca's, do you mean disconnect the RCA's from my amp?

Yep, that's exactly what he meant. 1moreamp asked me to do the same tests on my amp. Only power and remote wired up, no speakers or RCAs and take DC voltage reading on the speaker.

Brad06 · Post by **Brad06** » Mon Jul 30, 2007 6:21 pm

this may sound stupid, but do RCA's have dc voltage?

Brad06 · Post by **Brad06** » Mon Jul 30, 2007 6:25 pm

Am i reading the voltage of the amp or the speakers? 1more amp made it sound like i was testing the AMPLIFIERS speaker outputs, but you said test the speakers

Post by **fuzzysnuggleduck** » Mon Jul 30, 2007 6:27 pm

Brad06 wrote:Am i reading the voltage of the amp or the speakers? 1more amp made it sound like i was testing the AMPLIFIERS speaker outputs, but you said test the speakers

That was a typo, sorry. I meant to say speaker terminals on the amp.

Brad06 · Post by **Brad06** » Mon Jul 30, 2007 6:30 pm

thats what i thought you meant, but i was just checking!! when it comes to electrical, i check, check, recheck, and have another person check as well! however, he nor i seen anything wrong, but thats where the Volt meter comes in hand. Im going to the garage to test the amp, be back with results in a lil bit! and again, thanks for everyones help, it takes patience to deal with someone like me, always asking dumb questions!

Brad06 · Post by **Brad06** » Mon Jul 30, 2007 7:08 pm

Alright guys, i just finished testing the amp on 2 different volt meters, and they both say that there is no dc voltage coming from the speaker terminals on the amp. any other ideas?

Post by **fuzzysnuggleduck** » Mon Jul 30, 2007 8:25 pm

That's a good sign, if I recall correctly.

How accurate are your voltmeters/multimeters? Are they digital or analog?

1moreamp · Post by **1moreamp** » Mon Jul 30, 2007 8:32 pm

Evening, sorry I had to be away so long, Ahhh There will be some voltage on the output in the 0.010 or less range of volts DC < that 10 milli-volts or less depending on how new your amp is inside>

RCAs should NOT have DC voltage on them but I have tested many and seen as much as 0.600 volts DC Or about 1/2 a volt DC.

Its all good the builder know this so they use blocking caps on all the amps inputs just to block any DC products that might be there and be headed at you amp.

What I was worried about would be more like 12 to 45 volts DC on the speaker terminals Then your in real hurt the amps blown. Rockfords fail this way and smoke speakers when they do.

So at this point I must digress and ask where is the heat centered on your subs ? i.e. Voice coils ? Magnets? front of cone?

And do your speakers move freely back and forth with out and scratching, and or grabbing of the magnet voice coils assembly ?

I have seen bad speakers start grabbing the magnet and people just keep turning up the volume till they are fried and frozen completely, then the amp blows usually.

LMK what you find with you cone movement and where the heat is emanating from on the speakers..

PS I just repaired a RF 800.4 yesterday it had 14 Volts DC on the speaker terminals I removed the board from the sink to find a blown trace about three inch long and about 1/4 inch wide where the owner had hooked 12 volts to the speaker terminals and blown the circuit board trace on the bottom of the amp. Had to be the easiest repair Ive seen in a month, after I stopped laughing

Brad06 · Post by **Brad06** » Tue Jul 31, 2007 8:13 am

the speakers move freely, without any catching or scraping. the heat is coming from the cone. not hot, but warm.

Post by **VW337** » Tue Jul 31, 2007 8:41 am

Warm is not uncommon. Do a test similar to the last but with the RCA's connected to the amp. Leave all speakers disconnected and turn the volume up to your typical listening levels then using a meter read the DC voltage on the speaker output terminals of the amp.

If you register some DCV then this will indicate clipping, adjust the amp gain down until the DCV is eliminated or just quits lowering in value.