New Amp Time!

[Why So Cereal? 5,000+ posts]

One of the coolest amps I've ever owned was an old Fosgate Punch 360.6. Rated 30w a channel & had those X-Card crossovers, that thing had some balls...wish I could find another.
First thing I'd do is really verify that your amp is taking a dump and it isn't some other issue. Unless you've been cooking that channel below 2ohm, amp channels usually don't just 'go out' without some other variable added into the mix. For instance, if you've got a bad passive crossover it'll sound like an amp issue when it isn't. In addition, it could be your your HU or the interconnects between the two.

Make sure it is an amp problem first. No sense in buying a new amp when it's a bad speaker or something's touching chassis ground.

I noticed the problem when I pulled into my yard and put the car in park. I heard what sounded almost like a test tone in my front right channel. Turned the engine off and still got the noise, turned the music all the way down,still there; turned the CD player off (which also cut off the amps), noise gone; turned it back on, noise came back on. So I went to the amp. While listening to the noise, I played around with all of the wires on the amp. At first, I played around with the RCAs and it seemed to go away but then came back. Then, it stopped with the full tone and only when notes around certain frequencies (right around the xoverpoint of 300hz) played, it got really loud on one side and it was like I could hear that tone in the background of each "punch" in the music. Even put my hands on both doors and could feel that one was playing harder than the other at those frequencies most noticeably.

I swapped RCAs, and the problem persisted in that same channel. Then, I swapped the speakers to different channels and what ever speakers I had on that channel, same problem. Also took a DMM to my terminals while playing a 1khz test tone and it was constantly higher than the other channel on the same gain structure as it (so I'm assuming the lesser voltage one, is the bad one). The channel rests at 4 ohms as it is. I was baffled as to why I was having the issue as well. But, I did get it second hand after it had already been refurbished. That "tone" has not happened anymore, but I did have to use my left-right fader to even out the sound and get the center stage I'd once had. otherwise, that channel would get annoyingly loud before the other.

If you can think of anything I could have missed checking please LMK, I'd love to keep my own amp.

 

[BnGRacing 10+ year member]

If you can think of anything I could have missed checking please LMK, I'd love to keep my own amp.

With your DMM; check to see if there's continuity between the speaker lead & chassis ground. If you have a speaker terminal that's rubbed thru the paint in your door frame it'll cause that exact problem.

 

[Why So Cereal? 5,000+ posts]

With your DMM; check to see if there's continuity between the speaker lead & chassis ground. If you have a speaker terminal that's rubbed thru the paint in your door frame it'll cause that exact problem.

I dont see how that could be the problem because when I switched the speakers to different channels, whichever speaker was on the suspect channel was quieter.

but how exactly do I check this with my DMM?

 

[zako 10+ year member]

I read only the first post, and still feel confused about what exactly you need in an amplifier...

I have spent quite some time looking for a $200-$350-ish 5-channel amplifier. I was seriously leaning towards Alpine MRX-V60 or PPI PC740.5. Based on tests and reviews, these may not be the most powerful, but they're among the cleanest sounding amplifiers for the money. The Alpine is very compact too. In the end, I bought two relatively good 4-channels and 3-way power and ground distribution blocks for just $400. That's more expensive than 5-channel, but besides having better specs, I now also have two unused extra channels. I hope these will be used for rear fill when I have proper processing. However, for the money, that Boston GTA-1105 does seem like the best option. It seems like basically GTA-704 plus GTA-400m in one enclosure. These are probably just 'average' within their respective class, but at only $210 spent, I wouldn't complain. The only question is whether it makes sense to limit your choice by spending so little.

 

[Why So Cereal? 5,000+ posts]

Talked to BA on it today and......we were able to fix the issue using rubbing alcohol and my index finger in about 3 minutes //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif