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Old 29th February 2008, 06:05 PM   #1
Clipped is offline Clipped  Thailand
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Default 4 amps 3 subs

stuck on this one...

1. how much power would each sub see?
2. what ohm would best suit the middle sub to make things as even as possible between the three...and would it be truly even?
3. how many ohms would each amp see?
4. would one rail work harder than the other rail?
5. is this a stupid idea?

each amp puts out 600watts@ 4ohm mono (maybe a bit more)

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thanx
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Old 29th February 2008, 08:26 PM   #2
jol50 is offline jol50  United States
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I would never strap amps like that unless I knew exactly what I was doing with a particular amp. I never touch outputs of different amps. I would say get 2 ohm subs so you don't have to do that, or something like that instead of hooking them together. Often that will produce smoke from the amps from what I have seen. You could run different amps to different VCs of same sub, but that chart does not look right.
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Old 29th February 2008, 09:49 PM   #3
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A, I am not sure that it would actually work with the centre woofer.
B, I would mot do that because if there is any diferences between the amps and there will be they will be fighting each other on the same coil.
C, WHY?

Are these amps 2 ohm mono stable?
Why not run 1 sub at 8ohms on each amp bridged, it will still be 300wrms (assuming they are 2x150@4 ohms) and will have a higher damping factor than running at lower impedance so iwould work very well....
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Old 29th February 2008, 10:29 PM   #4
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The amps are only rated to 4 ohms mono so you're likely to blow the amps if you go lower.

If you had a load that was safe for the amp, you would have to tie the secondaries of al of the amps together with a large (8g+) wire to prevent oscillation or other problems.
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Old 1st March 2008, 07:07 AM   #5
ECM is offline ECM  United States
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So you were able to repair the 2150 after all?
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Old 2nd March 2008, 07:25 PM   #6
Clipped is offline Clipped  Thailand
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jol50......im not actually strapping the amps...
--------------------------------------
junglejuice, Today i tried 2 amps at 8 ohm mono each, it was just slightly louder and a bit tighter than one amp at 4ohm...maybe about 10% louder than one amp at 4 ohms, and got just as hot...low notes didnt have as much authority...as long as things are within 0.100 volts of each other it should be ok.
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Perry, im trying to figure out how many ohms each amp will see, since only 1 extra polarity terminal is hooked up, is the amp truly seeing another 4 ohm load (if the middle speaker was 4+4?)

when i measure the voice coil plus one extra polarity , the load still reads 4 ohms...but i think i should hook up 3 coils and measure it again.

would i have to tie together all 4 amps secondaries, or each pair that are seeing a common coil?

would i have to tie together the secondaries leg per leg? does the auxillary supply for the ps drive circuit have to be tied together also?

tying the secondaries together has me thinking now...would this make it possible to truly strap the amps together in parrallel? just curious.

------------------------------
ECM,remember the email i sent telling you it had been fixed bro?...i just didnt have a chance to test it after repair because i didnt have any insulators. the amp had an smp60n06 in place of the 16amp negative rectifier...factory defect i guess.

1 out of the 4 amps is way louder than the others...i think this is mainly do to the emitter resistor value change and the modified transistors used in the predrive/drivecircuit....the output transistor change shouldnt make this much difference (75watt vs 90watt) or should it?

all fets are the same for all amps, those 3205's are kickass, thanks Perry!
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Old 2nd March 2008, 10:44 PM   #7
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With 4 ohm coils, this would essentially be a 2 ohm mono load for the channels connected to the third speaker.

You would have to strap the amps together that were driving a common voice coil. You would tie the center-taps together, not the rails.

You wouldn't want to tie the rails together. If one output section failed, it could destroy both power supplies if the fuses didn't blow quickly enough.
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Old 3rd March 2008, 12:13 AM   #8
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I know this was asked....... but WHY?

Use one amp per speaker and save yourself a catastrophe. Keep the other as a spare or sell it for beer money.
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Old 3rd March 2008, 02:28 AM   #9
jol50 is offline jol50  United States
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If the leads of one VC touches more than one amp, I consider that some kind of strapping. Maybe not proper term.
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Old 3rd March 2008, 09:28 AM   #10
Clipped is offline Clipped  Thailand
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system plans keep changing, just exploring options to maximize power per sub.

i can fit 2-3 subs in the trunk and stay in the consumer class with the power i have and be competitive.

if i enter the 4 sub category, im not sure if i will have enough power to be competitive...and will have to enter the pro class do to no backseat...

if i go for 4 subs 4 amps i have to buy 4 new coils and do more testing to match the spiders and Mms...

besides this, i would love to be still be able to look out the back window.
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