Phoenix Gold Phorum

Hi, I am new to this forum but not to car audio. I recently purchased a second hand M100, I am having trouble with it Clipping all of the time. I have already blown the internal 50 amp fuse, I replaced it with a 60 amp. My question is about tuning, I cannot get much bass without the gain turned up and then it Clips. I am right in the middle of re-doing my entire system, I am the Original owner of a Route 66 that has run my system by itself for years. I wanted a little more power so I figured if I got a M100(similar look) I could run it dedicated to the subs. I have run 3 12" MTX Blue Thunders for years with the 66, I added the M100 and also added 3 New 12" MTX 1204 4ohm subs. I am now running my MTX 5500 8" mid bass from the sub out on the 66. The rest of the speakers are 2-6 1/2", 2 5 1/4" amd 4 Tweeters all running off of the 66. I definately have more bass but the amp is clipping all of the time on the big hits. I also recently add a Tsunami 40 Farad Capacitor, I have the right size wires and fuese. I need someone with a M100 to give me some tuning advice. Can anyone help me out. It is funny because I also painted the Heat Sink white on the 100 to match the Route 66, it looks great with the 66.
All of this is in my 69 Chevelle that is a full Show car and I have competed with it several times, I have never gone home without a trophy yet. Please help me out if you can, if you need any more info let me know, thanks Todd.

PIX OR BAN...............................

I"d like to see that dood.......

what procesor and headunit you using? is it just the clip light lighting up or is the system audibly clipping?

check all power wiring for goos solid connections especially the ground terminal where it attatched to the chassic.

So are you saying that your output is either really low or the amp clips? Could be some bad transistors, like when I fried my M100.

Do you have a DMM? Cecil might ask you for some DC offset readings from unloaded channels.

Welcome aboard.

How did you set your gains? Also what kind of Headunit do you have? If I recall correctly the m series amps only need a 2 volt input, so if you have a high power headunit that could be causing some of your problems.

Here is a tutorial on basic gain setting with a DMM.

http://phoenixphorum.com/gain-setting-w ... vt280.html

I don't know how you are setting your gains, but you might try this and see if the problem is still there. If it is I would have to think something is wrong with your amp.

Oh yeah, and like FuzzyHoNuts said PIX OR BAN!!!!

We like nice cars here....

Morning Todd, and welcome to the PG forum,

So your running 1.33 ohms load mono ( three 4 ohm loads in parallel ) on a 4 ohm / 2 ohm mono amp ??? This can be done but the gains will be very sensitive, and with todays high output HU's your easily going to overdrive this amp even at min gain settings. Min gain = 2 volts to get full output at any load on a M series amp. < as I recall, correct me if I am wrong please >

The big issue is the fact that the amps high current output due to the 0.675 ohm load to each channel when bridged in Mono... If you look up the specs for a M-100 your way too low with this sort of load. there is a spec for 2 ohms mono at 480 watts if you dig real deep into PG PDF files, and the amp needs a 70 to 90 amp fuse to do this sort of power.

So blown fuses are going to be expected with the load your pushing. the stock fuse will NOT cover this power level.

Now are the subs New and not broken in yet???
this is also important cause a new sub with stiff elastomer's will suck up just about anything you can throw at it, until all the flex parts break in and become flexible.

Another question, is the M-100 all original and untouched inside for the last 15 years of its life ???
If so it probably needs to be serviced. Service consists of All new power capacitors, some solder joint rework, and new heatsink compound, and a general alignment of the Bias idle set points, and a DC offset check to make sure the amp is not damaged by prior ownership. And anything else it may need to make it like new inside and operationally.
Excessive DC offset will cause the amp to shutdown in protection, and is a sign of previous abuse to the amp.

Now this is just a short list all concerning the amp, and the load your running. I would need to look inside the amp to spout any other info, and since I have no inside pics to work with I would be guessing and wasting your time....

M amps are NOT 1 ohm amps, they never were. They are great amps, and are 100% designed like the MS/MPS series in the amp channel ONLY. The power supply is NOT like the MS/MPS series, and therefore its power is limited below 2 ohms unlike the MS=MPS which has a stronger power supply with "no limitations" built in to them.

You should be blowing your doors off with this amp. but I don't really think your gonna get anything above the posted 480 watt spec by PG way back in the day. This amp has limitations inside, and your way outside its boundaries.

Can this amp be made to do what you want ? well that all depends. I think the amp should be serviced before even considering the load your pushing, The Amp is 15 years old if its a day, and you reving it way towards red line, and possibly beyond. This might be a very possible thing on a new amp, but a used one, of unknown condition inside ??? well I think you see where this is going...

PG has reasonable rates to revive this amp. I would offer but my plate is full and time is very important to everyone these days. Currently my window is not as fast as your other service opportunities.
Since your doubts are with the amp, may I suggest you get it professionally serviced by either PG or some reputable source that will show you all the details, and return all the replaced parts, and they must have the tools and gear to test the amp at the loads your running. < While You watch >

This will rule out 98% of all the Mom and Pop shops out there so be picky as hell about who gets inside your amp. I know these things cause I have 2000 watts of dummy loads and a 90 amp power supply sitting just above them on my bench. If your service people do not have this sort of test gear your getting ripped, cause they can't test your gear for you. And with what your doing, you need to Bench test the amp to see it works at these levels your reaching for....

If its the amp, a service and testing will tell you this right away, if the amp passes its tests on a service bench them your back at gains and power feeds and such as possible issues. A simple bench power test will tell you if its the amp < these usually run $40.00 and up, where and when possible >.....I hope this has been helpful on your quest....

PS you can check out our "How To FAQ" section for more tests and details for DC offset issues, and gain settings with a DMM... we have all been here before so I think we can help you....

you've got some great advice here so far chevelle but I just wanted to add one more thing. NEVER replace a fuse that repeatedly blows with a fuse rated for greater amperage. The fuse is blowing because there is an issue that needs to be addressed! By allowing more current down the troublesome circuit you could cause more damage to y our equipment.