posted
yeah yeah i need help. wow never thought i would say it. i need to know how to or have built for me a 3 amp bridging module so i can run 3 a7hcs to 1 dd 9515@2.8 ohm.
posted
Sorry to say so, but that's impossible.. there is no way to bridge 3 amps into a single load.. I've heard dd makes a tri-coil 9515, that's about the only way I can see those 3 amps working for you.. asuming you have a dvc, why not add a 4th a7hc and bridge each pair to a coil... or drop to 2 amps and bridge to the paralleled coils. (I'd do some inbox impedance measurements before trying that though)
posted
Without learning some new info, I tend to agree with RW. I'm sure you know that when you bridge two amps together you basically tie their output grounds together and use the "hot" outputs, with one in opposite polarity. So instead of the hot output swinging from say -50 to 50 volts referenced to the ground line it swings from -100 to 100 in reference to the other hot line. Now in theory you could tie the ground of one amp to the hot output of another amp and keep the same polarity for both amps to do the same thing, using the first amps ground and the second amps hot output. So theoretically you could wire up all three amps in series. But in reality this doesn't work unless the amps output sections are completely isolated from each other. In the case of most car amps the power supply is isolated with an opto coupler or some device so the output power rails are isolated from the car voltage. But in every amp I have seen the RCA ground is connected to the speaker output ground. So if you connect the amps as I outlined in the second example you have the ground of one of your RCAs at ground and one at the speaker output voltage, but the RCA grounds are physically connected together so you short out the one amps outputs. Maybe if your RCAs were completely isolated from each other as well as the rail voltages being isolated it may work. Or there is the possibility of running them all in parallel, but I haven't had the time to seriously think about that yet.
Posts: 2575 | From: GA | Registered: May 1999
| IP: Logged |
Where are you hooking the coils to in this configuration?
Your coil has two leads (per coil but they need to have the same signal) and regardless of which of the three amp outputs or ground you connect the coil to you will not get more output than using two amps bridged together
posted
3 phase audio... hmmm no I've been wanting to try the parallel approach for awhile now, everyone parallels their batteries for more current why not parallel amps.. (anyone reading this please don't try it unless you know what your doing) IE.. a 2000x puts out 2000watts @ 4 ohm mono (maybe more but this is for simplicity sake) say your real impedance at burp freq is 1 ohm (unlikely but possible) a 2000x at 1 ohm will shut off, die, show it's magic smoke etc.. but 4 2000x's all paralleled to the 1 ohm load in theory creat 4 times the power of the single amps (ya, 4x the amps.. 4x the power.. easy) so 8000 watts at 1 ohm, name another way to get that much power into a single 1 ohm load??? all of the amps would have to be doing EXACTLY the same thing (voltage output) or things would go screwy, it's hard to say if amps are close enough in reality (all amps make slightly different amounts of power even ones from the same batch) in theory it would work.... but in reality who knows.. maybe the next way for ss/extreme 1-2 guys to put in 10k-20k/sub
posted
4 2000x in parallel on a 4 ohm load would let out a GIGANTIC cloud of smoke.
Each amp is seeing approximately .25 ohms, and they're not balanced either. The speaker will momentarily get over several thousand watts and let out more smoke.
It's common and easy enough to bridge 2 amps together but I can't see any way of bridging a third. The best suggestion I've so far is to look for a tri-coil speaker. Besides, VC's are much cheaper than amps.
Posts: 768 | From: Ottawa, On, Canada | Registered: May 2000
| IP: Logged |
i know that a short will occur with the ground between amp and i know why!.. I agree with your explanation jc2 .. but..
Bridging amplifier it'like add their voltage (output in serie NOH?? )
Now just imagine that each amplifier switching power supply have insulated ground between input and output stage...(optical signal insulation) and also that the 12volts input is isolated from the rca and output... (optical signal insulation) I mean that between each amp part we just need amplitude variation and NOT AN OFFSET (from a ground)..that bad thing that make a short-circuit.. you see?
Or for the rca: using insulated high impedence tramsformer ... and seperated battery for the 12V input (in tis case each amp will be totally seperated and insulated)
finally wire the (+) output of the first amp to the (-) of the second ....in serie and take the - of the first amp and the + of the last amp...
THE ONLY PROBLEM IS THAT YOU'LL NEED AMPLIFIER ABLE TO DRIVE VERY HIGH CURRENT AT OUTPUT.. : DONT FORGET CURRENT=E/R and as the output voltage (E) is high as the current increase... (for a fixed load impedance)
EX: 50V with 2 ohms = 25 A 100V with 2 ohms = 50 A (good output stage!!) two green fuse(60A) needed!...
That's my oppinion... maybe my brain is living on big white storm on beatiful blue sky but...
[ 08-13-2001: Message edited by: Doctorbass ]
-------------------- Street A "not legal but not outlaw!" Score in my integra: -152.34 dB 51Hz TL sensor -157,1dB 51Hz AC mic
2005-2006 Street A Champion in Quebec province!
CRAZY TESTs: ||||||THE ONLY 6.5" TO SCORE 168.9dB(TL)OUTLAW IN THE WORLD with 6 Watts.|||||| -Crazy 5.25 Bose sub 1.1cu box: 138.0dB TL mic 55Hz with ONLY 100W ! ---------------------------------- www.teamxmax.com
Posts: 645 | From: Quebec city | Registered: Mar 2000
| IP: Logged |
posted
I agree that it is possible, and I believe it only needs what you have proposed. If the power supply is isolated like most are, you only need to isolate the input signal, and isolation transformers are pretty common for line level signals. Jensen transformer makes some that would work great. I've got some junk amps laying around, I may have to try this. Another thought is to use some transformers, by connection the primary windings to the amplifier outputs, you could connect the secondary windings in series to add the voltages. Again you have to make sure the primary and secondary windings are completely isolated, some Accumatch transformers are not if I remember correctly.
Posts: 2575 | From: GA | Registered: May 1999
| IP: Logged |
Printer-friendly view of this topic