JasonJones Posted September 9, 2009 Report Posted September 9, 2009 Ok... So not to start another one of THOSE topics.... I have 2 Fi BTL 18"s running off a Fosgate T4k and Kenwood DNX-9140 HU. Problem I'm having is: I initially had the subs wired to 1 Ohm so couple weeks ago I pull the box out (Disconnected all the terminals on the amps cuz their attached) and attempted to re-wire them down to .7 (Friend suggested this and said he knew how to wire them to that Impedance so I trusted him). Next thing you know after hooking everything up I turn on the vehicle and amp begins too boot up no motion in the subs just a snap then hiss immediately threw the T4k into protect. So I said he was a moron and checked the Impedance at the Amp and it was .3....................... So we pull it all back out again and re-wired it to 1 Ohm and thought we'd call it a day with me losing some trust in him... But thats where the problem starts..... Now when I turn on the vehicle or even turn it to accessory I am getting H U G E power feedback/alternator wine... I'm not talking minimal bullshit I mean like screaming hiss. It is less noticeable when the vehicle is off but still present. I tried isolating it by checking all power/grounds, replacing all speaker wire and RCA's and it still persists, even checked continuity on both the 4 Channel and T4ks grounds both are zero'd out. So I attempted to take a RCA cables right from out of the box from Fosgate and ran them outside the vehicle to the amps to make sure they weren't picking up feedback from my power runs or batteries still there. THIS IS KEY: When I disconnect the RCA's from EITHER the 4 Channel (Also Fosgate P400.4) or the T4k one or the other the feedback stops.... So either the Subs ALONE will play fine no feedback or the 4 Channel will play fine no feedback... This is extremely odd to me at first I thought it was a ground differential problem between the 4 Channel and the Mono that was causing it to try to pull extra grounding from the RCA's but its not.... If someone solves this I will be eternally greatful and even send $20 via PayPal! Thanks guys for being my inspiration and confidants!
lanman31337 Posted September 9, 2009 Report Posted September 9, 2009 Sounds like you have a ground loop or a ground issue. Ground the RCAs on the back of your deck to the chassis of your radio, run a ground from your radio right to your 4 channel amp, and make sure your grounds are clean. 2 - Audiopipe AP30001Ds 1 - Lanzar Opti Scion 600.4 4 - Lanzar Optidrive 1232D's 1 - Lanzar Opti 5.1 1 - Lanzar Opti 6.1 1 - Lanzar Opti 6C midbass 1 - Alphasonic PCT6551 1 - Lanzar VX830 1 - JBL 22 band EQ 1 - Lanzar SDBT75NU 1 - AudioControl Epic160
CASZ71 Posted September 9, 2009 Report Posted September 9, 2009 Sounds like you have a ground loop or a ground issue. Ground the RCAs on the back of your deck to the chassis of your radio, run a ground from your radio right to your 4 channel amp, and make sure your grounds are clean. This worked for mine.. better have $20 ready ha.. 2000 GMC sierra 1500 ext cab KMC XD Spy series rims Front doors Fosgate punch 6 1/2's stock tweets Rear doors Fosgate power 4x6's Probox 10 and box under rear seat Rockford fosgate R-500 Prime series amp (537 rms) 4 gauge wiring
lanman31337 Posted September 9, 2009 Report Posted September 9, 2009 I like paypal. If you hook up just your head unit to a jump pack or a battery that's not in your regular loop, the noise will be gone. There is a difference in resistances, and it is using the RCAs as grounds. 2 - Audiopipe AP30001Ds 1 - Lanzar Opti Scion 600.4 4 - Lanzar Optidrive 1232D's 1 - Lanzar Opti 5.1 1 - Lanzar Opti 6.1 1 - Lanzar Opti 6C midbass 1 - Alphasonic PCT6551 1 - Lanzar VX830 1 - JBL 22 band EQ 1 - Lanzar SDBT75NU 1 - AudioControl Epic160
JasonJones Posted September 10, 2009 Author Report Posted September 10, 2009 I like paypal. If you hook up just your head unit to a jump pack or a battery that's not in your regular loop, the noise will be gone. There is a difference in resistances, and it is using the RCAs as grounds. Thanks for the advice! I will try this tomorrow if it works out then I'll PM you for your PayPal. I thought this was the issue but threw it out the window when I checked my continuity on the MM and they both read 0.00 constant so I thought they were good grounds and the differential problem was out the window... But I'll try sending a ground from my H/U right to the 4 Channel and see how that works. Also what do you mean ground my RCA's out at the H/U chassis? How would I go about doing this? Just splice with some 20 gauge or something?
lanman31337 Posted September 10, 2009 Report Posted September 10, 2009 Yup, wrap some light gauge wire around the outside of the rcas and connect them to a screw on the head unit. Check my thread here - http://www.stevemeadedesigns.com/board/ind...showtopic=51975 - should help you out. Next question - how did you check the grounds? Have you checked from your front run to the rear run? Are you running multiple batteries? Loose or corroded grounds on those? How is your ground from your battery to alternator? 2 - Audiopipe AP30001Ds 1 - Lanzar Opti Scion 600.4 4 - Lanzar Optidrive 1232D's 1 - Lanzar Opti 5.1 1 - Lanzar Opti 6.1 1 - Lanzar Opti 6C midbass 1 - Alphasonic PCT6551 1 - Lanzar VX830 1 - JBL 22 band EQ 1 - Lanzar SDBT75NU 1 - AudioControl Epic160
JasonJones Posted September 10, 2009 Author Report Posted September 10, 2009 Yup, wrap some light gauge wire around the outside of the rcas and connect them to a screw on the head unit. Check my thread here - http://www.stevemeadedesigns.com/board/ind...showtopic=51975 - should help you out.Next question - how did you check the grounds? Have you checked from your front run to the rear run? Are you running multiple batteries? Loose or corroded grounds on those? How is your ground from your battery to alternator? Didn't get a chance to try this today, but I will try it. And I checked the continuity from the battery - terminal to the grounded point in the rear 2 D3100's and also checked it from the amplifier channel to the ground point on both amps. I have not checked from front lead to back lead. Big 3 is done all wiring is KnuKonceptz 1/0 and all terminals were crimped/soldered. Thanks pal I hope this works!
lanman31337 Posted September 11, 2009 Report Posted September 11, 2009 Take your time. Sometimes things are overlooked. 2 - Audiopipe AP30001Ds 1 - Lanzar Opti Scion 600.4 4 - Lanzar Optidrive 1232D's 1 - Lanzar Opti 5.1 1 - Lanzar Opti 6.1 1 - Lanzar Opti 6C midbass 1 - Alphasonic PCT6551 1 - Lanzar VX830 1 - JBL 22 band EQ 1 - Lanzar SDBT75NU 1 - AudioControl Epic160
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