You did not read what I and AJT posted.
We agree that the bridged delivers double the output into double the impedance.
yes two channels of 500W into 4ohms gives one channel of 1000W into 8ohms. Nothing has been gained. 500W+500W before bridging and 1000W after bridging
This is the bit where you have gone wrong 4 times just does not exist, it is not realisable.
Take an example from real life.
An amplifier is rated for 4ohms speaker duty.
It has maximum powers of 250W into 8r0 (+24dBV) and 400W into 4r0 (+23dBV) this is fairly typical of a commercial 4ohms rated amplifier and shows 1dBV lost when the resistance of the dummy load is reduced to the rated lowest impedance.
Now take two of these amplifiers which have a 400W+400W into 4+4 loading
and bridge them.
You now get one channel delivering 800W into 8r0.
There is no 4times anywhere !!!
There is no magic.
There is no extra power.
The total maximum power before bridging was 800W (400+400) and the total maximum power after bridging is 800W.
NOTHING has been gained.
But something has been given up.
The bridged amplifiers cannot drive a 4ohms reactive speaker load.
The question of bridging looks like the same question as a Stereo honey badgers with MJL21193/4 outputs to drive stereo 4 ohm speakers, and then how many watts does that do safely and what's the perfect voltage and right-sized VA transformer (that wouldn't exceed the outputs) to use?
The task of driving a stereo pair of 4 ohm speakers is not significantly different from bridging that same amp to drive one 8 ohm speaker.
How much output power do we get with the 12 output devices driving the one 8 ohm speaker?
The task of driving a stereo pair of 4 ohm speakers is not significantly different from bridging that same amp to drive one 8 ohm speaker.
How much output power do we get with the 12 output devices driving the one 8 ohm speaker?
Sorry for creating a stir. I meant by momoblock that what was once a stereo amp becomes a single channel "monoblock".
Perspective man, never anywhere I said amps were going to magically have more power. Ok. So instead of 1000W it's 800W due to losses.
One speaker, seeing 250W on one channel, sees 800W on two channels bridged. 800 / 250 = 3.2 . OK. Not quite 4, but close.
As for amp power, using one 8R speaker on one channel, the other channel doing nothing, the amp is giving out 250W. Into 8R. 1/4th of total amp power being used. Now, that same 8R on both channels bridged. Now the amp supplies its full power, assuming this to be a 2x500W/4R capable amp, for 1KW total power between two channels.
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The same math that says that 10 * 4 = 40. Again, I said, perspective. ~4x is entirely valid from the perspective of a speaker. 2x is entirely valid from the perspective of the amp.
Edit: It's simply where you are scientifically placing the 'Observer'. No more, no less.
The amp drives two 8ohm speakers at 250W each. That equals 500W total into 8 ohms. Bridged it drives only one 8ohm speaker at 800W. Your math is flawed. Are you a salesman in an audio store?
Put yourself in the speaker. Be the speaker. Connect yourself to one channel. What do you see?
Put yourself in the speaker. Be the speaker. Connect yourself to the two channels bridged. What do you see?
No flawed math, it's simple observer positioning.
Consider this scenario. For the sake of argument, take a near-perfect stereo amplifier that can output a maximum peak voltage of 20V (before clipping) into a 1 ohm minimum load, per channel. The rating of such an amplifier might be stated as 200W RMS per channel.
Now, again for the sake of argument, if the "normal" connected load is 8 ohms in stereo mode, this will give a maximum output power of (20^2) / 8 watts (peak), or 25W RMS per channel.
In bridged mode, driving one 8 ohm loudspeaker, this configuration will provide double the voltage swing, giving (40^2) / 8 watts (peak) = 100W RMS into the load, well within the capability of the amplifier.
Yes, this is four times the original power being delivered to the same load (based on doubling the voltage), BUT each amplifier must be capable of driving half of its original load impedance (due to doubling of the current) AND each amplifier must be capable of providing half of the total power. In reality, this is not a very practical "quick fix" for more power, but bridging can be useful where the available voltage output swing is limited and where specifications will not be exceeded.
Now, again for the sake of argument, if the "normal" connected load is 8 ohms in stereo mode, this will give a maximum output power of (20^2) / 8 watts (peak), or 25W RMS per channel.
In bridged mode, driving one 8 ohm loudspeaker, this configuration will provide double the voltage swing, giving (40^2) / 8 watts (peak) = 100W RMS into the load, well within the capability of the amplifier.
Yes, this is four times the original power being delivered to the same load (based on doubling the voltage), BUT each amplifier must be capable of driving half of its original load impedance (due to doubling of the current) AND each amplifier must be capable of providing half of the total power. In reality, this is not a very practical "quick fix" for more power, but bridging can be useful where the available voltage output swing is limited and where specifications will not be exceeded.
The difference between Currentflow's example and Terry's is that Terry is looking at a real life amp and currentflow is looking at theory. A commercial 250W/8R amp may not have the power supply or heat sinking to allow it to deliver the theoretical bridged power. Us DIYers on the other hand will be able to approach that theoretical output with our oversized PSU and heat sinks and conservatively de-rated output devices.
My Hafler DH-500 was rated exactly as Terry specified. My guess is the rated 4 ohm power was one channel driven.
My Hafler DH-500 was rated exactly as Terry specified. My guess is the rated 4 ohm power was one channel driven.
a bridge too far?
OK guys, I see both sides of the isle here. Let me just ask a direct question: if I jumper together my inputs to the boards and outputs from to board (taping over the unused "in" and "out" so as not to do something stupid) can I expect the Honey Badger to be better at driving a 6 Ohm subwoofer or should I just use one channel and save up money for a second subwoofer?
OK guys, I see both sides of the isle here. Let me just ask a direct question: if I jumper together my inputs to the boards and outputs from to board (taping over the unused "in" and "out" so as not to do something stupid) can I expect the Honey Badger to be better at driving a 6 Ohm subwoofer or should I just use one channel and save up money for a second subwoofer?
How efficient is your sub? I have a JBL B380. When I built my P101 I built it 3 channel. I used the center channel to drive my sub using the BX63. I had to turn down the sub to keep it from being too loud. I see guys building huge amps to power their subs but i am not convinced that is necessary. I would think a bridged Honey Badger would be all that is needed unless you are doing outdoor concerts. The only problem is that in bridged mode the amp sees half the ohm of the speaker so if your speaker sees 3 ohm. That may be too low for the Badger. You would have to ask OS.