wiring question

[NIHL8ION]

Thanks for all the info so far, it is a 92 Volvo 740 wagon, yes stock alt and batt. I came up with the 35.35vac by 1250 x 1ohm = 1250 & sq root of 1250 = 35.35. Is this wrong? My brother in law has a hifonics Brutus with 1200rms rating and a swr-10d2 sub at 1ohm and it slams pretty good, gonna do an amp swap tonight and see if it does better in his system, may help pinpoint wether its my power or the amp. I'll report back later this evening.

If the amp swap does nothing for you, I'd try a HU swap to see if it's a signal issue...

 

[Jepalan]

I came up with the 35.35vac by 1250 x 1ohm = 1250 & sq root of 1250 = 35.35. Is this wrong?

Your calculation is correct, theoretically. But the amp is not going to be able to produce 1250 W RMS. The spec is exaggerated. In order to put 1250W into the sub, the amp would have to pull almost 120 amps from the battery (at 80% efficiency). Tell me how 120 amps are going to flow through the 80 amp fuse built into the amp?

Regardless, this is just splitting hairs - I am sure it will slam pretty good. Point was that you are never going to get 35 volts into a 1 ohm sub - lower your expectations a little. That said, I would still expect more than 13.6v. Good luck. Keep us posted on progress.

 

[Doug535]

If the amp swap does nothing for you, I'd try a HU swap to see if it's a signal issue...

Think we're onto something here. Swapped my amp into his setup and BAM, it thumps just fine. I believe the HU isn't outputting enough through the RCA's. Testing in his setup we could get 50VAC easy. *****, cause I just got the HU a couple months ago. Well I'll give that a go in the next few days and report back.

Censored out s u c k s? haha

 

[Side Show 10+ year member]

sweet, progress!

 

[Doug535]

Your calculation is correct, theoretically. But the amp is not going to be able to produce 1250 W RMS. The spec is exaggerated. In order to put 1250W into the sub, the amp would have to pull almost 120 amps from the battery (at 80% efficiency). Tell me how 120 amps are going to flow through the 80 amp fuse built into the amp?
Regardless, this is just splitting hairs - I am sure it will slam pretty good. Point was that you are never going to get 35 volts into a 1 ohm sub - lower your expectations a little. That said, I would still expect more than 13.6v. Good luck. Keep us posted on progress.

Ha, expectations not that high but I did expect better than 13VAC

 

[Jepalan]

Think we're onto something here. Swapped my amp into his setup and BAM, it thumps just fine. I believe the HU isn't outputting enough through the RCA's. Testing in his setup we could get 50VAC easy. *****, cause I just got the HU a couple months ago. Well I'll give that a go in the next few days and report back.
Censored out s u c k s? haha

I'm not sure I understand what you are saying above. It sounds like you swapped out the amp and it worked, but you still think the problem might be with the HU. I don't understand the logic.

Regardless, if you have been swapping RCAs on in and out, you may have blown the pico fuses in the Pioneer HU - which breaks the RCA ground connection and will kill the RCA signal level. Try grounding the RCAs to the HU chassis like shown here. Look at the HU in the background, note how the wires attach to a chassis screw...

 

[robert420 10+ year member]

Thanks for all the info so far, it is a 92 Volvo 740 wagon, yes stock alt and batt. I came up with the 35.35vac by 1250 x 1ohm = 1250 & sq root of 1250 = 35.35. Is this wrong? My brother in law has a hifonics Brutus with 1200rms rating and a swr-10d2 sub at 1ohm and it slams pretty good, gonna do an amp swap tonight and see if it does better in his system, may help pinpoint wether its my power or the amp. I'll report back later this evening.

random, i know. but how much are you looking to get for that Volvo?

 

[Doug535]

I'm not sure I understand what you are saying above. It sounds like you swapped out the amp and it worked, but you still think the problem might be with the HU. I don't understand the logic.
Regardless, if you have been swapping RCAs on in and out, you may have blown the pico fuses in the Pioneer HU - which breaks the RCA ground connection and will kill the RCA signal level. Try grounding the RCAs to the HU chassis like shown here. Look at the HU in the background, note how the wires attach to a chassis screw...

Did this for a horrible squeal issue when I got the HU, should have been a tip to get a different HU then.

I swapped MY amp into HIS system to eliminate it being the amp. The amp checked out ok in his system. Did voltage drop test from battery to amp, all good. Did ground resistance test and I'm @ 00.2ohm, all good there.

 

[Doug535]

random, i know. but how much are you looking to get for that Volvo?

Not for sale, I've had her since 2001 but thanks for asking you never know.

 

[Jepalan]

Did this for a horrible squeal issue when I got the HU, should have been a tip to get a different HU then.
I swapped MY amp into HIS system to eliminate it being the amp. The amp checked out ok in his system. Did voltage drop test from battery to amp, all good. Did ground resistance test and I'm @ 00.2ohm, all good there.

OK, now we are getting somewhere.

I think you already know the answer.

Get new head unit. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[jrdnhsnbrg 10+ year member]

There's no way you're going to even THINK about getting close to 1250W RMS with stock battery, alternator and wiring in a 92 Volvo. Do the big 3 and get a good AGM battery. If you have the cash get a HO alt too.

 

[jrdnhsnbrg 10+ year member]

Not to mention the new HU, as discussed above.

 

[Side Show 10+ year member]

battery and headunit issue

 

[Jeffdachef 5,000+ posts]

Man lots of problems due to weak/screwed up head units lately. **** companies cheaping out on headunit build quality on the lower models.

 

[audiobaun 5,000+ posts]

A dollar save is twenty earned to audio makers.they prob have 15 yr olds soldering boards 23 hrs out of the day with two pi ss breaks