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spnkysprky
Lv 5
spnkysprky asked in Cars & TransportationCar Audio · 1 decade ago

Experienced installers please.I have a question about ohm/resistance on a older model amp.RF Punch 200x2?

First let me start by telling you what Im running.Initially I was running a rockford punch 200x2(dsm) transana with 2 OLD school punch 12's.The 12's are the older series aound early 90's.They are only 100 watts nominal/Rms and 4 ohms each.I was running a 12 to each channel.Being that these particular subs are NOT very loud,I decided to add a 3rd 12 that I had lying around.This sub is a polk audio around 300 watts rms(i think) and also 4 ohms.

Ok,I am running all 3 subs in what I call "tri-mode".Which is 1 12" on each channel at 4 ohms and 1 12"(The polk) Bridged at 4 ohms at the same time.It actually sounded really nice.

However,for reasons unknown (because it happened when My girlfriend was driving/listening)one sub was overheated and on the verge of blowing.My girlfriend said she was jamming out real loud and began to smell something burning.Every since then,it sounds weak.

My guess is she was clipping the amp at an extreme level and was unable to hear it due 2 the polks bass

Update:

was drowning out any sound of extreme distortion/clipping.The polk was considerably louder than the OLD punch 12's.Or the gains were slightly off.It may even be that I bought the subs used and they are over 10 years old.Whatever the case may be....thats NOT my question.

My question is....I have another sub I can use.Its an oldschool JBL dual 4 ohm.So now Im stuck with 2 - 4 ohms subs and 1 dual 4 ohm sub.Since I can only run the JBL at either 2 ohms or 8 ohms I was thinking of still running in "tri-mode" BUT running the JBL on 1 channel at 2 ohms and another sub on the 2nd channel at 4 ohms and the polk bridged at 4 ohms.

Question is...will this effect the performance of the amp?Im sure you CAN run 1 channel @ 2 ohms and the other at 4 ohms because each channel has independant gain adjustments.But can I do this in tri-mode?Im thinking NO because that 1 channel will be running at 2 ohms which most likely will require a different gain setting than the other channel..

Update 2:

And being that I want bridge,this requires that both channels are adjusted equally....Am I right?? Or can I just lower the sensitivity(gain) on both channels and make the equal.I am aware that this will cause 1 sub to get more power (which is ok because the 2 ohm sub is 180 watts rms as opposed to the 100 watts rms punch.

Will this hurt the amp?This will be only for about 2 months,then Im buying NEW subs. Boston acoustic G5 series.

Sorry for the LONG post...Any suggestion would be appreciated.I know this is somewhat of "rigging",but humor me.:)

Update 3:

Thanks for both answers but I know what Im doing as far as wiring and so forth.I have run a complete entire system of a Old punch 200 before.Im talking 2 subs and 8 mids and highs all of 1 amp.The older rockfords are designed that way In FACT if you look thru almost ANY older rockford amps manual,it will give you a diagram to do so.The only draw back is you have to use a passive crossover for the subs because the amp requires a full range or all pass signal. .And yes,adding more subs does add more bass...Thats a given....more subs equals more air displacement.

As far as the burnt smell,its definately the sub\....You can smell it inside the enclosure.

As I said before...Im looking for EXPERIENCED answers.I just need to know if the amp can take it.Im not worried about over heating...Ive got a cooling fan mounted. MDC,Sparky or any pros got a suggestion?

Update 4:

Joshua,YES I am aware of that.I already mentioned that.Thats actually ok because the 2 ohm speaker is higher wattage than the 4 ohm subs.

And Vaughn....The punch 200 is capable of pumping out 500 to 600 watts RMS in bridged mode.Depending on the amp.These amps are called "cheater" amps....You have to be an old fart to know this.Ive been doing this since 1989 bro

Update 5:

I meant joshua on the amps specs.Its dynamic power is actual around 200 or so watts x 2 @ 2 0hms and 500 or more x 1 @ 4 OHMS.The last punch 200 I had pumped 589 watts x 1 @ 4 ohms with 13.8 volts

Update 6:

Thanks RPM....I know the DSM can handle a 2 ohm load mono.....but they are not supposed to LOL! Im too scared to run at a 2 ohm bridged because I fried one once before.It didnt fry right away....it took a few months.I ran that amp hard!...It ran for about 5 to 6 months. I was young and stupid....I just dont want to make the same mistake.Now I will only run 2 ohm Bridged when I need extra power for a show off contest lol!Real short periods of time.Now I will run 2 ohm stereo all day if I could.

Also,I didnt want to bridged the punch....I have a polk audio thats about 200 to 300 watts rms.So it would be a punch on ch 1 and JBL at 2 ohms on ch 2 and bridged would be the polk at 4 ohms.

4 Answers

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  • MDC
    Lv 6
    1 decade ago
    Favorite Answer

    I may have read it wrong but the Polk was the one that overheated and you have the two Rockfords right? Or was it that one of the Rockfords that overheated?

    I would run one punch on each channel. Then I would take the JBL and wire it to a 8 ohm load then bridge it. However, you would want to be a little careful on the gain still because the JBL may be overpowered a little bit.

    If one of the Punchs overheated and you have the Polk left then I would try wiring the Punch on one channel. Then take the JBL and run a single voice coil on another channel. Then both channels are at 4 ohms. Finally take the Polk and bridge it.

    Edit: I read below and saw that you did say that you have the Polk still so it was one of the Punchs that overheated. So, like I said above, would just run a single voice coil on that JBL. Since the power handling is 180w you won't need to worry about it overheating.

    Both channels would have to be the same impedance for the tri-mode to work effectively.

    Good luck with your setup. I'm sure your going to have one wierd box in your car with three different subs, lol.

    Source(s): http://www.mdcustomz.com/
  • RPM
    Lv 6
    1 decade ago

    Old school Fosgate ... got to like those "cheater" amps of its time, particularly @ competitions.

    Tri-mode, Ch1 & Ch2 have to be ran at the same impedance. As you already pointed out, that's not an issue if you run the amp in stereo mode as each of the channels have independent gain adjustments. There isn't an issue if you run two 4-ohm subs on Ch 1/2 and run the JBL bridged at 2 ohm. As you know, the DSM amps are plenty capable of it.

    Edit: I misread it too ... One of the Fosgate subs blew and so now there's a Polk, JBL & the old school Fosgate sub in the equation. I definitely now see your dilemna because your highest power handling sub's impedance (Polk) is 4 ohm (which you will use in bridged mode) and the two subs (JBL/Punch) you want to run off Ch 1/2 have mismatched impedances.

    Source(s): http://www.rockfordfosgate.com/scripts/rightnow.cf...
  • vaughn688
    Lv 4
    1 decade ago

    Wow.. Umm. That smell is a burning amp. Now. This is probably the first time I've heard of this, but hey.. It happens. You can't run one sub per channel AND bridge another sub into 2-channel amp. The amp will see the ohm loads and say "Wtf?!" So. I don't think you mentioned the coil configuration so I'll quickly explain it.

    One 4-Ohm Single Voice Coil sub = 4-Ohms

    Two 4-Ohm Single Voice Coil subs = 2- or 8-Ohms

    One 4-Ohm Dual Voice Coil sub = 2- or 8-Ohms

    Two 4-Ohm Dual Voice Coil subs = 1- or 4-Ohms

    Three 4-Ohm Single Voice Coil subs = 1.34- or 12-Ohms

    Three 4-Ohm Dual Voice Coil subs = 2.67- or 6-Ohms

    Don't try to tangle a bunch of different model/size woofers together. I recommend finding your amps Watt @ Ohm load rating and use the small chart I wrote above to wire them correctly. Remember, adding more speakers don't give you more bass. The amp can only divide the power equally to each speaker that's connected to it. Hope that saves a few coils and amps for you.

    Source(s): Me
  • Anonymous
    1 decade ago

    im not completely familiar with "tri mode" but you do realize that

    the channel with the 2 ohm load will draw more power than the channel at the 4 ohm load....... possibly causing cancellation issues as well as the amp getting extra hot extra fast...ive experimented in ways like this myself and found that the best way to improve the performance of your audio system if youre not satisfied with it is to sell the old one and spend more money on what you need......and even though thats a rockford amp i just dont see a 400 watts amp(if its bridged) taking on 3 12s effeciently...im not saying im right im just saying thats what my experience tells me...im not a pro installer but ive learned a lot from painful hours of trial and error

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