Just modded a MTX 1501D, makes a whine noise?

[gc86 10+ year member]

Hey all, well I was looking on craigslist earlier today just browsing around and some guy was selling a MTX 1501D for 180 bucks!! so I jumped on the deal drove up to his house tested the amp and all, everything worked out great. Got home and researched on modding the 1501D because i've heard about people modding it to make it 1ohm stable and lower, so I busted out the oldschool radioshack soldering iron and went to work on it, did a search on the forums and found a thread explaining how to desolder the Q240 chip, well I went through with it willing to accept the risks and now I have a successfully modded 1501D. Just hooked it up to my d2 ohm XXX wired to 1ohm and it worked out perfect, haven't done much testing on how stable it is since I just modded it like 30min ago lol but its making everything in my car dim. Now on to a little concern, the amp makes a whinning noise when its on driving the sub and it varies with how I turn the gain knobs and phase switch. Is this normal?

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[SAG3 5,000+ posts]

its the alternator whine, probably something wrong with your ground.

 

[kotec123 10+ year member]

its pprobly your alternator whining...or maybe the whine is a warning that the ohm load level is too low

 

[ngsm13 5,000+ posts]

Did you also UNdepress the compression circuit?

NG

 

[gc86 10+ year member]

nvm

 

[gc86 10+ year member]

bump.... the whine is comming from the amp itself.. not the sub

 

[gc86 10+ year member]

couldn't i just get a yellow top and call it a day? i think my elec system is fairly strong, its a new 04 mitsubishi

edit: i used the amp today for about 2 hours during my commute and when i got home the amp was pretty warm, is this normal?

 

[Blados 10+ year member]

couldn't i just get a yellow top and call it a day? i think my elec system is fairly strong, its a new 04 mitsubishi
edit: i used the amp today for about 2 hours during my commute and when i got home the amp was pretty warm, is this normal?

New battery will help, but probably wont' solve the problem. Yeah, the amp is going to get warm, it's running at 1 ohm now.

 

[gc86 10+ year member]

bump.. still waiting for a response from somebody who has experience with modded 1501d's/81000d's or owns one

 

[SuperTrooper 10+ year member]

I have a 1501d, not modified. but when installed it i had engine noise I'm assuming. Which I never had that problem before. I just used a larger gauge wire for the ground and that fixed my prob. But if you said it's coming from the amp istself, thats an *** scratcher to me. Good Luck.

 

[noob with an RS 10+ year member]

hey ive got a modded 1501d modded by scottieJ himself //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif my amp does that too. they all do. i think even without the mod. its normal. its not a big deal it gets louder the more it's amplifying the signal.. so you're not gonna hear it when you have subs connected to the amp. awesome amp. even better awesome buy considering you got it for only 180. i got my 1501d for 320 //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif mine doesn't even feel warm at all really pushing my idMAX.. its only giving it about 500 watts most of the time though..

EDIT: didn't read the post above.. i guess the mod makes it make that noise???

 

[thch 10+ year member]

bump.... the whine is comming from the amp itself.. not the sub

i was about to ask that. if the speaker made noise, it'd be an output filter / output stage issue.

i think that it still is. though. listen to the amp and fine out where the noise is coming from. my bet is the inductors on the output filter, or the input transformer was not made for this and is moving (very slightly). amp noises are typically moving inductors/transformers or capacitors. i have an old home amp that literally plays music with no speakers attached!

 

[gc86 10+ year member]

hey ive got a modded 1501d modded by scottieJ himself //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif my amp does that too. they all do. i think even without the mod. its normal. its not a big deal it gets louder the more it's amplifying the signal.. so you're not gonna hear it when you have subs connected to the amp. awesome amp. even better awesome buy considering you got it for only 180. i got my 1501d for 320 //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif mine doesn't even feel warm at all really pushing my idMAX.. its only giving it about 500 watts most of the time though..
EDIT: didn't read the post above.. i guess the mod makes it make that noise???

glad to hear yours does it too, now i dont feel that worried anymore, but regarding the heat issue, it was warm to the touch after 2 hours of hard bumping all the way home so i mean i guess its gonna get warm.

 

[gc86 10+ year member]

Need to get yourself a stronger electrical system if you haven't done so already...the alt would be your best upgrade right now since that amp pulls 150 amps +.

what other mods do you have beside your alt? i dont know if i wanna spend much more money on this car lol im broke as it is and a new bat + alt is $$$

 

[gc86 10+ year member]

how long have you guys ran your modded 1501ds or 81000ds at 1ohm? months years etc.