Phoenix Gold Phorum

my question is this
if you have a real 4 channel amp not 2 amp under one cover and i a person was to only use the rear channel for sub duty will this harm your amp?
if not do you need to add the rca into it ect
let me know
thanks

the amp will be a ppi pc4100?

I ran an old fosgate series one amp that way for years in my truck until I left the back window open and it got rained on. Depends on the amp.

cecil would tell you that it puts an unbalanced load on the amp's power supply and 80% of the 4 channel amps he repaired were broken in this way.

i would also say, the only time i ever blowed up an amp was running it in that way...


i have NO other factual data or experience to add anything other then that...

Bfowler wrote:cecil would tell you that it puts an unbalanced load on the amp's power supply and 80% of the 4 channel amps he repaired were broken in this way.

i would also say, the only time i ever blowed up an amp was running it in that way...


i have NO other factual data or experience to add anything other then that...

so is there a way to make a dummy load or just wire the oem front till i have time to get other in that way it will be used on sound going from it just the gain not turned up as much?

I don't know why the others above have had problems, but there's no reason (legit reason) why it would ever harm an amp to run it that way. If anything, the amp will be breathing easy. You simply want to match the load with what the manufacturer recommends ( 4 ohm bridged for instance), but it doesn't matter if you are using only two of the channels for this and leaving two channels dead.

Relevant thread here: http://phoenixphorum.com/viewtopic.php?f=3&t=3087

shawn k wrote:I don't know why the others above have had problems, but there's no reason (legit reason) why it would ever harm an amp to run it that way. If anything, the amp will be breathing easy. You simply want to match the load with what the manufacturer recommends ( 4 ohm bridged for instance), but it doesn't matter if you are using only two of the channels for this and leaving two channels dead.

shawn it make sense but also the info tom post does... anyone know anything about old pc ppi amp? i thought single power supply but not sure
i truly don't have a clue how ams work i can look at one to see if there is damage but other than install thats about it

kg1961 wrote:

shawn k wrote:I don't know why the others above have had problems, but there's no reason (legit reason) why it would ever harm an amp to run it that way. If anything, the amp will be breathing easy. You simply want to match the load with what the manufacturer recommends ( 4 ohm bridged for instance), but it doesn't matter if you are using only two of the channels for this and leaving two channels dead.

shawn it make sense but also the info tom post does... anyone know anything about old pc ppi amp? i thought single power supply but not sure
i truly don't have a clue how ams work i can look at one to see if there is damage but other than install thats about it

I have a couple of those PC amps myself. Including the PC4800.2 which is essentially the same amp you have. It is a single power supply amp.

There's no need to dive into an old thread and debate ideas from several years ago, but I will stand by what I said earlier in that you will be just fine by running only two of your channels and leaving two of them unused.

I will even go as far for you to say this: If you decide to run your amp with only two channels in bridged mode, with no less than a 4ohm load as recommended by PPI, I will repair your amp for free if the output stage on the two used channels fails! All you have to do is cover shipping. Hopefully this shows you how confident I am with this. No BS... I will fix it free of charge!

shawn k wrote:

kg1961 wrote:

shawn k wrote:I don't know why the others above have had problems, but there's no reason (legit reason) why it would ever harm an amp to run it that way. If anything, the amp will be breathing easy. You simply want to match the load with what the manufacturer recommends ( 4 ohm bridged for instance), but it doesn't matter if you are using only two of the channels for this and leaving two channels dead.

shawn it make sense but also the info tom post does... anyone know anything about old pc ppi amp? i thought single power supply but not sure
i truly don't have a clue how ams work i can look at one to see if there is damage but other than install thats about it

I have a couple of those PC amps myself. Including the PC4800.2 which is essentially the same amp you have. It is a single power supply amp.

There's no need to dive into an old thread and debate ideas from several years ago, but I will stand by what I said earlier in that you will be just fine by running only two of your channels and leaving two of them unused.

I will even go as far for you to say this: If you decide to run your amp with only two channels in bridged mode, with no less than a 4ohm load as recommended by PPI, I will repair your amp for free if the output stage on the two used channels fails! All you have to do is cover shipping. Hopefully this shows you how confident I am with this. No BS... I will fix it free of charge!

sold shawn i will find some time in the next 2 weeks have to sell a car work 6 days a week but i will install it soon
i will let you know
any problem if i use the bass knob?ect it will be the jbl 12" with paper kelvar cone dual 2ohm wired to 4 300 watt rms 97db sen.

kg1961 wrote:sold shawn i will find some time in the next 2 weeks have to sell a car work 6 days a week but i will install it soon
i will let you know
any problem if i use the bass knob?ect it will be the jbl 12" with paper kelvar cone dual 2ohm wired to 4 300 watt rms 97db sen.

Well sure you can use it, but would suggest only sparingly. I actually never recommend using bass boosts of any kind. At low levels they're fine and can be a nice bump to overcome road noise, but at the same time, they can be a real problem if abused. They can and will cause an amp to clip prematurely so keep that in mind

I'm no specialist on amps but I know electricity and electronics. To me this question is like asking: I have four lamps in my house. Will I break anything if I only turn two of them on?

Same situation when you turn on your amp but don't play any music. Not gonna break.

I only use one channel out of two with my sub amp. Sounds great prolly because the power supply is having a field day only delivering a quarter of its full capacity. The rail voltage probably stays nice and even (and high) this way.

If you don't exceed the ratings, no 4-channel amp should fail due to only using half of it.

If an amp were rated at say 50W x 4 into 4 ohms, and 100W x 4 into 2 ohms, with no rating for 1 ohm, then running only 2 channels of it into a pair of 2 ohm loads would get you 100W x 2, and not put any strain on the amp.

My guess is the problem arises when someone thinks that this same amp should do 200W x 2 into 1 ohm. In this case the power supply should be good for it (still 400W total), however the amp likely only has half the needed output transistors for this power, which will result in the channels being used failing.