posted
Your first sentence is correct. But the rest is where you lose it. Nowhere does he say that he is getting doubled voltage. The 25 amps continues through the load and you get twice the voltage for 200 volts.
200 volts multiplied by 25 amps is 5000 watts, which is exactly what he claimed.
quote:Originally posted by Sassmaster: actually, every time you double the voltage, you don't double the current, you need to do a little studying of ohm's law... watts = volts times amps, if you doubled the voltage, with the same power, you'd cut the current in half, and if oyu doubled the wattage, you'd either double the voltage OR the current. if you doubled both it'd quadruple the wattage.
you really need a lesson in basic electrical theory.
P=EI Power (watts) = Energy (volts) X Intensity (current, in amps)
so from your example, 25 amps X 100 volts equals 2500 watts, which is true.
50 amps times 200 volts doesn't equal 5000 does it?
no it equals 10,000
25 amps times 200 volts or 50 amps times 100 volts.
the 2 do not rise linearly in relation to each other.
if you double your wattage so 2P you'd need to either have to double the voltage or current. not both.
Amplifiers are basically voltage regulated, variable frequency power supplies, where you can vary the frequency output by inputting a lower level switching signal. the voltage stays the same no matter what load, so if you're paralleling 2 sets of amplifiers, you will have the same voltage as if you just had one set of amplifiers. but the current would double.
if you're wiring the amps in series, you'd have the same current, but your voltage would increase, but since the voltage is regulated, there is a very finite limit to the increase.
read up a little on electrical theory.
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Posts: 1587 | From: Springfield, MO | Registered: Oct 1999
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posted
I did some research on "optocouplers" last night.... found some interesting stuff Nothing that would solve our problem directly, but you could definitely make some type of device from this if need be.
I think i'm going to take a trip down to my not-so-friendly neighborhood radioshack today and see what they have for transformers... just for kicks
-------------------- Nate Scholten Team Sounds And Motion SS 1-2 3rd place 2004 finals -THE BUILD- ~Our Drinking Team Has A Stereo Problem~ Posts: 4253 | From: Rhinelander,WI | Registered: Dec 1999
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quote:Originally posted by netlohcs: I did some research on "optocouplers" last night.... found some interesting stuff Nothing that would solve our problem directly, but you could definitely make some type of device from this if need be.
I think i'm going to take a trip down to my not-so-friendly neighborhood radioshack today and see what they have for transformers... just for kicks
An optocoupler is basically a led or light that turns on a switch. Picture it as a little midget in a chip, when he sees the light come on he flip the switch to on.
The transformer, if on the speaker outputs, must be rated at the proper wattage or VA (VOLTS X AMP) rating. Since you will most likely be dealing with about 1000 Watts per amp you will need a 1 KVA transformer. It should handle about 2 to 4 Thousand watts for a short time. The frequency we use will be around the 50 to 60 hertz range where regular industry standard electrical transformer or available.
the only problem will be back EMF into the amp, good thing is if one amp blows it will not seriously effect the other amps.
-------------------- My 45's want fit in that slot! Posts: 1169 | From: Rowlett, TX, USA | Registered: Jun 2000
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posted
Okay guys, this has been a very interesting thread... One of the better ones i've read in quite some time. But tell me if i'm reading this correctly. I don't think it is exactly what i saw in the picture, but you are talking about wiring the amps in series using multiple batteries, with at least one battery per amp, with the amps and batteries running in series? Meaning, The first amp is running at +12V with a 0V ground, and the second amp is running at +24V with a 12V ground, the third at +36V with a 24V ground, and so on? Or am i just way out in left field? If so, is this possible? Would it do anything?
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quote:Originally posted by oldtimer: An optocoupler is basically a led or light that turns on a switch. Picture it as a little midget in a chip, when he sees the light come on he flip the switch to on.
The transformer, if on the speaker outputs, must be rated at the proper wattage or VA (VOLTS X AMP) rating. Since you will most likely be dealing with about 1000 Watts per amp you will need a 1 KVA transformer. It should handle about 2 to 4 Thousand watts for a short time. The frequency we use will be around the 50 to 60 hertz range where regular industry standard electrical transformer or available.
the only problem will be back EMF into the amp, good thing is if one amp blows it will not seriously effect the other amps.
As far as optocouplers go, thats essentially what i gathered, and that is pretty much how a digital optocoupler works. However there were also some sites that spoke of analog optocouplers (thus i would assume there are such things?), which is what i was referring to. Sorry I didn't clarify. Using some type of Analog optocoupler, i'm sure you could fully isolate the necessary audio circuits.
As for the transformers you speak of, it sounds like you are talking about wiring them on the output side of the amplifiers? That is not exactly what I had in mind, not saying it wouldnt work though. It seems that the setup you refer to would be inherently less efficent due to power losses in the transformers.
The isolation that I was talking about occurrs before the input side of the amplifiers, and then the amplifiers themselves are physically wired in series (speaker + from one amp goes into the speaker - of the next amp).
-------------------- Nate Scholten Team Sounds And Motion SS 1-2 3rd place 2004 finals -THE BUILD- ~Our Drinking Team Has A Stereo Problem~ Posts: 4253 | From: Rhinelander,WI | Registered: Dec 1999
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quote:Originally posted by Xplisit Kontent: Okay guys, this has been a very interesting thread... One of the better ones i've read in quite some time. But tell me if i'm reading this correctly. I don't think it is exactly what i saw in the picture, but you are talking about wiring the amps in series using multiple batteries, with at least one battery per amp, with the amps and batteries running in series? Meaning, The first amp is running at +12V with a 0V ground, and the second amp is running at +24V with a 12V ground, the third at +36V with a 24V ground, and so on? Or am i just way out in left field? If so, is this possible? Would it do anything?
This seems like it could be the case, but actually each bank of batteries would be isolated from one another, meaning there would be no voltage (or continuity for that matter) present between them while the entire system was at rest.
While being played (burped) the grounds of each amp-battery combination are changing in reference to one another in an AC manner. Say your amplifiers produce 100 volts (on the output side). Then there will be an AC voltage of 100 volts between each subsequent battery ground.
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As for the transformers you speak of, it sounds like you are talking about wiring them on the output side of the amplifiers? That is not exactly what I had in mind, not saying it wouldnt work though. It seems that the setup you refer to would be inherently less efficent due to power losses in the transformers.
Transformers run in the upper 90's on efficency. typically around 98%
-------------------- My 45's want fit in that slot! Posts: 1169 | From: Rowlett, TX, USA | Registered: Jun 2000
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quote:Originally posted by oldtimer: This is too easy. Look at the old booster amps. They were nothing but transformers.Wire as many amps as you wish in phase just to keep it simple. Add a 1 to 1 transformer or so to the speaker outputs. series the output of the transformers together.
you now have electrical isolated outputs which can be added together.
You are kidding me right? So to stack 4 amps on one coil all i need is an old booster amp for this method, isolated batteries per amp, and isolated signals?
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posted
no the old booster amp had small transformers. You need big transformers on the output and no where else. You will have to watch the equivilent ohm load to each amp. You could use accumatches at each output and wire them in series too, just size them for multiple loads.
-------------------- My 45's want fit in that slot! Posts: 1169 | From: Rowlett, TX, USA | Registered: Jun 2000
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posted
With your idea of putting the ouputs of the amps in series would increase the voltage thus increasing the current going through you output transistors, right? Those little guys are only rated for so much current. Is there an rules against, say, poping the cover off the amps and wireing a few more transistors in parallel with the originals? This would allow more current to pass through since the new and the old ones would share in the task.
Posts: 4 | From: Houghton Michigan | Registered: Dec 2001
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quote:Originally posted by Crazy8s: With your idea of putting the ouputs of the amps in series would increase the voltage thus increasing the current going through you output transistors, right? Those little guys are only rated for so much current. Is there an rules against, say, poping the cover off the amps and wireing a few more transistors in parallel with the originals? This would allow more current to pass through since the new and the old ones would share in the task.
You are correct. That's why he says that if each amp is 2 ohm stable by itself, then you'd need a 4 ohm load to run 2 in this manner, or an 8 ohm load to run 4 in this manner, etc. So the voltage goes up, but the current stays the same. Power is V*A, so even if you keep the current the same, the power still goes up as you keep adding amplifiers.
posted
i'm still confused on how we're going to achieve more power by just isolating the batteries and signal, and then wiring the amps in series at the speaker outs... Explain to me, please, since the amp gets it's power from the battery, not the speaker terminal, that this is going to increase power. Is it stepping up rail voltage? If so, how? If not, what is it doing? I'm not doubting here, I would just like to understand.
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posted
Its not stepping up any voltages inside the amp, but rather summing the voltages created by each amplifier.
Say you have two 12 volt batteries... now say you wire them in series.
Did the voltage of each individual battery go up? ... No
Did the OVERALL voltage of the system go up?.... YES
-------------------- Nate Scholten Team Sounds And Motion SS 1-2 3rd place 2004 finals -THE BUILD- ~Our Drinking Team Has A Stereo Problem~ Posts: 4253 | From: Rhinelander,WI | Registered: Dec 1999
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quote:Originally posted by netlohcs: Its not stepping up any voltages inside the amp, but rather summing the voltages created by each amplifier.
Say you have two 12 volt batteries... now say you wire them in series.
Did the voltage of each individual battery go up? ... No
Did the OVERALL voltage of the system go up?.... YES
^^^ What he said. This method doesn't produce any more power from each amp, but it DOES allow you to use as many amps as you need in order to get however much power you want to a given load. If you had a dual 4 ohm sub, you could run 8 amps to it if they are 1 ohm stable, or even 16 if they are .5 ohm stable. Each amp will put out the same power as if it were on a 1 (or .5) ohm load, but since you have so many more of them, your overall power is much higher.
posted
The whole battery analogy is not flying with me... Because batteries just store and release power. With amps, you are talking about changing a DC 'wave' into an AC signal. I think it's gonna take some technical talk to get me to understand. I'm no expert, but i've studied my fair share of audio/amplifier/electical theory books.
Now where am i wrong here? I'll list the things i am taking as truths:
An amp turn a DC wave into an AC wave of considerable more power
The power put out by the amp is determined solely by the potential differences between the two rails inside the amp.
The rail voltage is determined by the power supply voltage, and increases as supply voltage increases in amps with unregulated power supplies.
The only way to increase power sent to a voice coil is to create a larger potential difference/voltage between the two terminals of the coil.
Current flowing through the coil is directly proportional to the voltage supplied, since the overall impedence is fixed (yes, it varies with frequency, i know)
So given that much, here is what i am seeing going on, simplified a little:
The first amp is run off of 12V. It has 0V at one rail, and 10V at the other, for example. The maximum voltage between the two speaker terminals is 10V. We'll say at one point in a wave, it is reading 0V at the negative, and 10V at the positive. Maximum transient power. Now we have this second amp, also wired to a 12V power source, however isolated from the first. Since it is identical, it also can produce a max of 10V difference between the two terminals. It's being fed exactly the same signal, and we're freezing time at the same point, so at this instant there is the maximum difference of 10V between them, with 0V at the negative and 10V at the positive. (i know this sounds redundant, but bear with me) So we take the 10V coming from the positive terminal of amp #1 and plug it into the negative terminal of amp #2. There is obviously a difference in voltage here, so current will flow across here, i agree. But the positive terminal of amp #2 is still at 10V due to the 12V power supply. It cannot produce any more voltage here. We're plugging (-) from amp #1 into our imaginary sub, and the (+) from amp #2 into the other end of the voice coil. Now there is still only a difference of 10V across the coil. That's where i get stuck.
By the way, great thread! It's got me thinking. I hope i can understand this whole tihng, and get a better understanding of how amps work. But i'm still very sceptical... I figured the hundreds (thousands?) of EE's out there who devote time and effort to designing amps would have figured this trick out already and exploited it...
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posted
Xplicit, I think you'd be a little more clear on it if you realize that voltages are only relative. This setup is kind of confusing because there are many individual grounds in the setup, and during burps their relative voltages to one another are constantly changing. I'll try and post a more specific explination with some diagrams in the next day or so, if I get a chance.
DDCherokee, unfortunately diodes wouldn't do the job. A diode only prohibits the flow of reverse current through it... which wouldn't really isolate it.
I am a little more optimistic about transformers however I went to radio shack yesterday and picked up myself some "audio isolation transformers".... $3.99 each.
They are only rated from 300hz-5000hz however i did a tiny little bit of testing and concluded that they were capable of transferring frequencies below 300... how well i'm nost sure. If the fundamental principle works though, i'm sure much better transformers could be used. I have not yet used them in any isolation setup, as of yet. I will be doing this soon though.. and will report back with results.
-------------------- Nate Scholten Team Sounds And Motion SS 1-2 3rd place 2004 finals -THE BUILD- ~Our Drinking Team Has A Stereo Problem~ Posts: 4253 | From: Rhinelander,WI | Registered: Dec 1999
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posted
Well, I have done some research on this subject and have found that there are at least 3 ways to strap amplifiers.
(1) The conventional way: One amp representing the (+) side of the wave and one amp representing the (-) side of the wave then "linking" them together on one coil.
(2) Then there is the idea of wiring the outputs in parallel. With this style, a person would have to cut the impedence in half, and the outputs would have to be matched exactly at ALL times. There are ways to do this, I know.
(3) Then there is this idea of wiring the amps in series. The voltage output of each amp would be additive. This style also eliminates the problem of matching the outputs.
Now, I have recently looked in to the last two styles. I also have talked to a person that has done both styles w/ 4000 watt amplifiers. He said it can be done, BUT there is virtually no gain. In fact, he stated that unless a person has an unlimited supply of subs, amps, and needs to gain MAYBE 0.1db-0.5db overall, then it is worthless to do this. I am not saying that nobody should do this, but I thought a few of you might want to know some results from testing these ideas.
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posted
One more thing about this input isolation problem. I am fairly sure that there is a company that makes a line driver in which the outputs can be totally isolated from each other. There are jumpers in side the line driver that allows you to select whether you want the outputs to be isolated or not.
Later,
Jason Meyer
-------------------- 2004 SS 1-2NW World Champion 2005 World Finals SS 1-2NW 2nd Place 2006 World Finals SS 1-2NW 3rd Place Team Maxxsonics Member of Broken Silence Competition Team Posts: 194 | From: Sedalia, MO, USA | Registered: Aug 2000
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quote:Originally posted by Meyer: One more thing about this input isolation problem. I am fairly sure that there is a company that makes a line driver in which the outputs can be totally isolated from each other. There are jumpers in side the line driver that allows you to select whether you want the outputs to be isolated or not.
Later,
Jason Meyer
What company is this? and where can i get one??
-------------------- Nate Scholten Team Sounds And Motion SS 1-2 3rd place 2004 finals -THE BUILD- ~Our Drinking Team Has A Stereo Problem~ Posts: 4253 | From: Rhinelander,WI | Registered: Dec 1999
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quote:Originally posted by Meyer: Now, I have recently looked in to the last two styles. I also have talked to a person that has done both styles w/ 4000 watt amplifiers. He said it can be done, BUT there is virtually no gain. In fact, he stated that unless a person has an unlimited supply of subs, amps, and needs to gain MAYBE 0.1db-0.5db overall, then it is worthless to do this. I am not saying that nobody should do this, but I thought a few of you might want to know some results from testing these ideas.
I find this quite interesting... because if you are able to strap amps correctly, you should be getting exactly DOUBLE power to your woofer. So this person only gained .1-.5 db from doubling amplifier power?
With this setup, someone that was running quads could rewire their amplifiers to produce essentially the EXACT same power into the same woofers (going to "dual" coils). I must admit i have never tried it personally, but i would think that you would gain more than .1 db when doubling power on a sub.
If this person has indeed tried exactly what we are saying then i do not doubt what he said... just expressing my thoughts.
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posted
Well, the reason for such a small gain is because the amplifiers efficiency is drastically reduced. The amplifiers are not being used as they were designed. I am not sure if you know this, but when you strap 2 Bd1501's together, their effeciency drops to 25%; and these amps are designed to do this. Just think of what happens to an amplifiers effeciency when not being used properly. Another reason, is that you lose a lot of energy to heat. Essentually, energy is power, so you can't afford to lose too much of it. I will try to get more detailed information, but I am sure thiguys tests were legit as one of my good friends was a witness to them.
So, when it comes to competing in the lanes, if you want to strap say 8 Mojo's on 4 coils----more power to ya. Just don't be surprised if someone w/ 4 Mojo's beats you. Like I said before, it can be done but the results were far less then satisfactory.
Later,
Jason Meyer
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posted
One thing I left out earlier was that how can a person "properly" strap an amp that is not designed too? Amps are not batteries. You can't just series there outputs and expect to double your voltage. There are far too many other factors involved. I am not trying to argue at all. I know for a fact that a person can strap just about any amp. However, I feel very confident that it is not very advantageous to do so. At least not with amps that are not designed too. On the other hand, go ahead and do further testing. Maybe there was something this other guy missed.
Later,
Jason Meyer
-------------------- 2004 SS 1-2NW World Champion 2005 World Finals SS 1-2NW 2nd Place 2006 World Finals SS 1-2NW 3rd Place Team Maxxsonics Member of Broken Silence Competition Team Posts: 194 | From: Sedalia, MO, USA | Registered: Aug 2000
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quote:Originally posted by Meyer: Amps are not batteries. You can't just series there outputs and expect to double your voltage.
That's what i'm saying. They do not produce their own power, they merely transform power from one form to another. It's not as simple as a bettery.
I never stated that it was as simple as a battery. I merely used this analogy for some of you who seemed to have a tough time understanding what was happening in general.
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