Come on you guys, you are saying the same thing.
The OPs amp as configured is not capable of driving a 4 ohm load.
And as Andrew says, the amp is not magically capable of outputting more power, you are simply halving the load each channel sees.
dave
Tony, you have to understand I am a noob in electrical & electronics field. Though I am an engineer, I specialize in IT and am very good in writing computer programs.
But I have the same analytical & reasoning skills that every engineer posses. Also just analytical skill does to help you to DIY amplifiers. You need further knowledge & experience in the field which I desperately lack. I do not have the instruments required to do the measurement. I was thinking to make an amplifier myself & buy the hardware required to do so.
I want to make a 2.1 audio amplifier. I have got a four TDA7296, two of which I want to use for each satellites, and another two TDA7296 bridged together for the sub.
But it seems though a single TDA7296 are well capable to handle +/-26VDC, the bridged TDA7296 can only handle upto +/-22VDC at 8 ohms. So, according to all you gurus it is better to use a pair of TDA7295 bridged together for the sub at 8 ohms as they somehow mange to accept +/-26VDC while bridged together.
1)I have a 150.9VA--> 20.1 X 2, 3.75A toroidal transformer
2) A pair of 10,000uf, 35V capacitors that I want to use as ripple filters
So, I am going to get a pair of TDA7295.
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They do see half the load, if one amp receives the same signal as the other amp but antiphase. This is true irrespective of whether the signal is shared between them or not. As I said, this is the opposite of bootstrapping. Bootstrapping (in-phase) increases the effective resistance, bridging (anti-phase) reduces it.
I don't know what else to say. You just need to go away and think about it. Hint: there is a virtual ground at the middle of the load. Think of the load as a see-saw being pushed in opposite directions at the two ends.
Hi,
as an example of a real life situation:
Take a DVC driver with 4+4ohm Voice Coils.
Take two 4ohm capable amplifiers that are specified as 250W into 4r0,
Connect one amplifier to one Voice Coil. Connect the other amplifier to the other Voice Coil.
The total maximum output to the voice coils is 250W+250W = 500W
Now, series connect the two DVC voice coils. You effectively have an 8ohm rated speaker.
Bridge connect the two 250W amplifiers.
Connect them to the 8ohm DVC speaker.
The maximum power output to the voice coils is 500W.
The bridging rule applies exactly:- double the power into double the impedance.
Note also that no extra power is delivered to the DVC speaker. In both cases, bridged and driven separately, the maximum power is 500W.
As far as I can see, the only advantage to bridge connection is to allow use of lower voltage supply rails.
as an example of a real life situation:
Take a DVC driver with 4+4ohm Voice Coils.
Take two 4ohm capable amplifiers that are specified as 250W into 4r0,
Connect one amplifier to one Voice Coil. Connect the other amplifier to the other Voice Coil.
The total maximum output to the voice coils is 250W+250W = 500W
Now, series connect the two DVC voice coils. You effectively have an 8ohm rated speaker.
Bridge connect the two 250W amplifiers.
Connect them to the 8ohm DVC speaker.
The maximum power output to the voice coils is 500W.
The bridging rule applies exactly:- double the power into double the impedance.
Note also that no extra power is delivered to the DVC speaker. In both cases, bridged and driven separately, the maximum power is 500W.
As far as I can see, the only advantage to bridge connection is to allow use of lower voltage supply rails.
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You also forgot to mention the lack of bus pumping and that a bridged topology can be run from a single supply (if designed for that).
single supply? Are you serious that this is an advantage and that it is exclusive to bridged topology?
"Bus Pumping"?
You can't be referring to omnibus so I'll be presumptuous and assume you mean the advantage that balanced amplifiers have on their supplies. I don't believe this is an advantage of bridged.
Why go through that rigmarole?
If you double the voltage across a given load, the current doubles as well.
Simple as that.
se
It is, but only when you're running in class A. In that case, there's a constant current draw on the power supply.
se
Sorry for that then. I don't own any Class A/B/AB amps, so I guess I just have a Class-D mindset.
i want to bridge Elliots 300w subwoofer link 300/500W Subwoofer Power Amplifier can someone help me with a working bridgind adapter?
Hi Guys!
I´m new in town, so please bear with me!
Ohm law states that Voltage= resist x Current. And Power=Current x voltage. If an amp delivers 10v RMS into a 4Ohm resistor then it will draw 2,5 amps. This makes 25w.
If an amp is driven in bridged mode, then there will be 20v over 4 ohms. This draws double the current (5amps) at double the voltage (20v). 20v x 5amps= 100w!
The problem usualy lies in the power supplys current capability.
Have a nice day!
I´m new in town, so please bear with me!
Ohm law states that Voltage= resist x Current. And Power=Current x voltage. If an amp delivers 10v RMS into a 4Ohm resistor then it will draw 2,5 amps. This makes 25w.
If an amp is driven in bridged mode, then there will be 20v over 4 ohms. This draws double the current (5amps) at double the voltage (20v). 20v x 5amps= 100w!
The problem usualy lies in the power supplys current capability.
Have a nice day!
The problem usually lies in the amplifiers' current capability.
That is why you don't get 4times the power.
Thanks AndrewT
A strong PSU alone dosen´t make a powerfull amp!
well, it is just half of the amp, and depends on what you mean by strong.....
strong because the rails are high and doesn't drop much under load?
again, having a strong psu, you need to match that with your trannies and heatsinking....
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