SA-12s bottoming out.

[Jeffdachef 5,000+ posts]

LMAO man come to Texas and demo Audiobaun's truck on those VFL Hybrids

I owned one back then. These amps are either hit or miss with their crappy quality control. Im certain that with his amp, he got one of the bad ones that dont put out for ****, even a 1500 korean will outright destroy that amp.

 

[Dmac1991]

I owned one back then. These amps are either hit or miss with their crappy quality control. Im certain that with his amp, he got one of the bad ones that dont put out for ****, even a 1500 korean will outright destroy that amp.

touche

 

[poolman966554]

ok. ive read how to set amp gains using the following formula E=PxR. i understand ohms law to an extent.

i dont see how this can prevent possible clipping. what if i had a BOSS 5000w and tried to set gains accordingly to get 2500w rms? the amp dont have it in it.

so im my case, say i wanna push 1500w @1 ohm to the sa 12s from my AB 4480.1. math here is easy.

square root of 1500 is 38.729V

so i set my gains accordingly(all sound setting neutral) , how do i know if im not clipping the amp? obvs the boss amp wouldnt prolly reach the destination voltage, if it did, not clean..

I think the real question i need answered is, how to i "match" rca preamp voltage to amp gain voltage?

i think im missing something in the formula.. how is my "2V" equated into the E=PxR?

maybe an example with the given numbers?

 

[poolman966554]

i didnt mean to start a war guys, just looking for possible options and more knowledge!

 

[Jeffdachef 5,000+ posts]

ok. ive read how to set amp gains using the following formula E=PxR. i understand ohms law to an extent.i dont see how this can prevent possible clipping. what if i had a BOSS 5000w and tried to set gains accordingly to get 2500w rms? the amp dont have it in it.

so im my case, say i wanna push 1500w @1 ohm to the sa 12s from my AB 4480.1. math here is easy.

square root of 1500 is 38.729V

so i set my gains accordingly(all sound setting neutral) , how do i know if im not clipping the amp? obvs the boss amp wouldnt prolly reach the destination voltage, if it did, not clean..

I think the real question i need answered is, how to i "match" rca preamp voltage to amp gain voltage?

i think im missing something in the formula.. how is my "2V" equated into the E=PxR?

maybe an example with the given numbers?

You need to test your rcas out and see what volume/sub level it needs to be at to get 2 volt preout. Then set the gains using that formula.

 

[poolman966554]

You need to test your rcas out and see what volume/sub level it needs to be at to get 2 volt preout. Then set the gains using that formula.

that makes better sense. thank you Jeff.

how will i know when to stop? if i increase the bass via eq it would raise the pre amp voltage correct?

would i need to have a scope on the rcas?

maybe the cheap one i posted a bit ago?

Edit : seller could have said it have 5v pre amp output? how would i know the difference? iu would need a o scope correct?

 

[Jeffdachef 5,000+ posts]

that makes better sense. thank you Jeff.
how will i know when to stop? if i increase the bass via eq it would raise the pre amp voltage correct?

would i need to have a scope on the rcas?

maybe the cheap one i posted a bit ago?

Edit : seller could have said it have 5v pre amp output? how would i know the difference? iu would need a o scope correct?

That oscope will definitely help in keeping things clean with the signal. You want to leave all bass eq flat when setting gains. Even after setting gains, you only reduce and never boost as boosting will kill sound quality most of the times and distort the signal at higher volumes.

Keep loudness off too.

 

[poolman966554]

That oscope will definitely help in keeping things clean with the signal. You want to leave all bass eq flat when setting gains. Even after setting gains, you only reduce and never boost as boosting will kill sound quality most of the times and distort the signal at higher volumes.
Keep loudness off too.

cool. thanks for the help. ill try that oscope and see how it goes. if i run into issues, ill video my experience and come back to this thread. thanks again for the help guys.

 

[BassAndBeer]

to much port area?

 

[audiobaun 5,000+ posts]

All in all..My amps do pretty decent..looking at your sig Mr. poolman,of your supply source for your amp could be the main culprit for supply starvation.One small agm on stock alt isnt enough for sure..as well as have you gotten that ELD bypass done or not as well for the CRV? Im sure Bass Boost has alot to do with your bottoming out/tuning..But Id deff recommend getting the Big3 done pretty quick as well as placing another batt in the rear(like a a group sized 34/78 AGM) for supply,and look into the ELD bypass being done on the stock alt.That amp needs supply, and as of right now its deff being starved.Its a great amp with the proper supply..Im running two of the same sized batts one under the hood with the airbox taken out with an air intake for the room to place one there and in the tire well in the rear grounded at the rear frame..with 2ga throughout for big3 with ELD Bypass on the stock alt seems to have plenty of power thus far..My pair of SQ HDS310s tens are in 4.0Cuft@32 htz..Im wondering if those 12s are in too small of an enclosure?Im not a box builder, but that may be another issue as well?Something to research as well.That amp needs supply though.That little batt and stock alt isnt gonna get it for sure man, and deff not getting the ELD bypass done...You will end up cooking that amp, and in the process end up clipping stage and possibly ruin a sub/subs in the process.Ive already experienced that in that vehicle,and can say..it isnt worth it not doing it right the first time..Just my experience of that vehicle

 

[Jeffdachef 5,000+ posts]

Again, my experience with the vfl 4480.1 hybrid. Electricals at the time was two kinetik hc1800s in the trunk, 180 amp singer alt on an 03 corolla. Had a hifonics bxi 1610d, 80 prs with strong preouts. With the hifonics, gain only needed to be at 60 percent to achieve proper ac signal and subs were loud. Directly put in the vfl 4480.1 hybird, extremely weak output at normal acceptable gain levels. I had a dmm on it and at 70% gain, i only got 28 volts which is around 800 watts.... , at that point the subs were just distorting, not even bottoming out. Highest i got out of it was 34 volts which is 1200 watts and thats with bass boost on and gians cranked. Output was still weak and dirty sounding compared to the hifonics, subs were making a sound like bottoming out but had no output to back it up. Put back in the 1610.d brutus and bam, everything was loud.

Im not the only one that has experienced low output problems from these amps, there has been threads on here and other people on CACO having beef with this amp. You guys can back the amp all you want, you might get one of those good early production lines that actually makes power or whatnot but you cannot turn a blind eye to many people that have used these amps properly and got burned for buying a vfl hybrid.

 

[sonicknuckles49]

dont use ur bass boost at all. a americanbass 4480 would be more than enough power to them. if ur subs are bottoming out all you gotta do is not turn the volume up so high, but if ur like me and that not possible try turning down ur gain and try setting ur subsonic filter a little higher . go through ur head unit setting and make sure nothings ( cranked up) make sure the bass boost is off and stuff on ur headunit.

 

[nauc 10+ year member]

set your gain right

heres how... https://jlaudio.zendesk.com/entries/22363097-Amplifier-Level-Setting-Guide

and this is what it sounds like when the amp clips, if you do it by ear..



heres the test tones. use the 0db 40hz tone.. Realm of Excursion