Gday,
Is it possible to bridge any stereo amp simply by connecting your speakers to the positive termanils and haveing a mono opposite input?
Thankyou
Or does it have to be built for this operation.
Daniel Priscared@hotmail.com
Is it possible to bridge any stereo amp simply by connecting your speakers to the positive termanils and haveing a mono opposite input?
Thankyou
Or does it have to be built for this operation.
Daniel Priscared@hotmail.com
Most amps could be bridged, but many cannot. The main factor is if the grounds or black binding posts of each channel are common to each other and to the ground power supply.
Some amps have the equivelent of a balanced output and both positive and negeative posts swing agianst the other to create a potential that the speaker "floats" between. Classic case of Single Ended Output Vs Balanced Output.
My advice: If you are not sure, do not try. It could be an expensive and smokey mistake. Conventional wisdom says bridging will give you 2 times the power but that translates into only 3dB louder. is it worth it?
Aud_Mot
Some amps have the equivelent of a balanced output and both positive and negeative posts swing agianst the other to create a potential that the speaker "floats" between. Classic case of Single Ended Output Vs Balanced Output.
My advice: If you are not sure, do not try. It could be an expensive and smokey mistake. Conventional wisdom says bridging will give you 2 times the power but that translates into only 3dB louder. is it worth it?
Aud_Mot
Aud_Mot said:
Erm..... not quite true.
If your standard amplifier is capable of doubling current
into half your loudspeakers impedance load its not.
(e.g. 60W into 8 ohm > 100W into 4 ohm)
P = Vsquared/R or IsquaredxR, either way its times 4 = 6dB.
(with the above example assuming current limiting = > +4.5dB)
But what is true is an amplifier that cannot drive low impedance
loads is not suitable for bridging, and that low impedance speakers
are not suitable as a load for bridged amplifiers.
I completely agree with the sentiment "is it worth it ?" nearly
allways its not as the speakers are not a good load for bridging.
(Unless we are talking about car audio etc)
sreten.
Using a bridged amp to drive a 4 ohm speaker is dodgey. The reson is that from the amp's point of view (pardon the anthromorphology) is will see not 4 ohms but 2. That's real low for many amps and smoke the output transistors or at least activate short circuit protection.
That's no to say you can't do it but a large number of amps (Most, perhaps) won't do well. That said I did this once with a Carver M-400 with no appearent harm, although thinking about it kept me kind of puckered up.
That's no to say you can't do it but a large number of amps (Most, perhaps) won't do well. That said I did this once with a Carver M-400 with no appearent harm, although thinking about it kept me kind of puckered up.
But, presenting an amp that is capable of driving two four ohm loads with a single eight ohm load in bridge mode should not be a problem. I'd like to know if it's as simple as:
1. Connect the same signal to both left and right amplifier inputs.
2. Connect the load to the positive output terminals of the two channels.
As posted previously in this thread, both amp channels must share a common ground for this to work. Am I missing anything? This is new ground for me, but very interesting.
dooper
1. Connect the same signal to both left and right amplifier inputs.
2. Connect the load to the positive output terminals of the two channels.
As posted previously in this thread, both amp channels must share a common ground for this to work. Am I missing anything? This is new ground for me, but very interesting.
dooper
me...
The reason i started this thread as i have a yamaha p2200 and it has in the manual"bridgable" however i was gunna replace one of its channels with a different model. But anyway. I wouldnt bother with bridging an amp unless u have high indepedance circuit speakers. also if u look at the dB of things, thwice as powerful isnt twice as loud between 300w and 600w?? So anyway
Daniel
The reason i started this thread as i have a yamaha p2200 and it has in the manual"bridgable" however i was gunna replace one of its channels with a different model. But anyway. I wouldnt bother with bridging an amp unless u have high indepedance circuit speakers. also if u look at the dB of things, thwice as powerful isnt twice as loud between 300w and 600w?? So anyway
Daniel
Daniel,
If I read you last post correctly, you were thinking of using one bridged Yamaha p2200 for one channel and an amplifier of another type for the other channel? Forget it, if it is a stereo apllication, do not bother. All the power you gain (by bridging) will be lost in having to pad down the channel that is higher gain to match the other amp.
In the spirit of the original question:
The process has 2 steps:
1- Feed the same signal to both channels BUT invert one of the inputs. This step by itself is a little tricky because what can happen when you start gounding the output of one device (example a preamp) and feeding the "ground" (not always zero volts) to the input of another . If you want to do it, a simple active device might be in order.
2- Your speaker output is the positive (red or +) of each channel. You do not use either of the speaker grounds.
Why this works. Do not try this at home!
Let us pretend you have an amplifier that is a 10x gain amp. You put +.1 volt DC into one of the channels. The amp would give you +1 volt DC out. (assume our amp is non-inverting) If you put -.1 volt DC, you would get -1 volt DC. If you do both (+.1 volt into channel A and -.1 volt into channel B) one will go positive, the other will go negative and across the 2 you will have 2 volts difference. +1 subtract 2 = -1, a difference of 2. That is how you double the voltage output.
Some one has earlier pointed out that 2x voltage = 2x current (assuming load does not change). Power = voltage x current so delta 2x (volts) mulitpled delta 2x (current) = 4 times the power (watts). Conventional wisdom says bridging only doubles your power, not quadruple. I guess it depends on how close your amp is to a perfect voltage source.
To be honest I have never worried about it that much. It isn't going to much louder in either case.
Aud_Mot
If I read you last post correctly, you were thinking of using one bridged Yamaha p2200 for one channel and an amplifier of another type for the other channel? Forget it, if it is a stereo apllication, do not bother. All the power you gain (by bridging) will be lost in having to pad down the channel that is higher gain to match the other amp.
In the spirit of the original question:
The process has 2 steps:
1- Feed the same signal to both channels BUT invert one of the inputs. This step by itself is a little tricky because what can happen when you start gounding the output of one device (example a preamp) and feeding the "ground" (not always zero volts) to the input of another . If you want to do it, a simple active device might be in order.
2- Your speaker output is the positive (red or +) of each channel. You do not use either of the speaker grounds.
Why this works. Do not try this at home!
Let us pretend you have an amplifier that is a 10x gain amp. You put +.1 volt DC into one of the channels. The amp would give you +1 volt DC out. (assume our amp is non-inverting) If you put -.1 volt DC, you would get -1 volt DC. If you do both (+.1 volt into channel A and -.1 volt into channel B) one will go positive, the other will go negative and across the 2 you will have 2 volts difference. +1 subtract 2 = -1, a difference of 2. That is how you double the voltage output.
Some one has earlier pointed out that 2x voltage = 2x current (assuming load does not change). Power = voltage x current so delta 2x (volts) mulitpled delta 2x (current) = 4 times the power (watts). Conventional wisdom says bridging only doubles your power, not quadruple. I guess it depends on how close your amp is to a perfect voltage source.
To be honest I have never worried about it that much. It isn't going to much louder in either case.
Aud_Mot
hmm no u read it wrong actually
No my amp has one channel 230w into 8 ohm. THe other channel is dead (reads 80vdc on the output) So i was gunna replace that whole channel not using yamaha parts. Now what i was wondering is would i still be able to bridge the amp. But as it happens one of my caps (100v 22000uf) has blown up and the cap will cost me way too much to replace ($100) So im hoping someone might be able to sell me one cheaper.
Thanks Anyway
I dont really think id need to bridge it . I think in mono mode its rated at 800watt into 16 ohms.
Daniel
No my amp has one channel 230w into 8 ohm. THe other channel is dead (reads 80vdc on the output) So i was gunna replace that whole channel not using yamaha parts. Now what i was wondering is would i still be able to bridge the amp. But as it happens one of my caps (100v 22000uf) has blown up and the cap will cost me way too much to replace ($100) So im hoping someone might be able to sell me one cheaper.
Thanks Anyway
I dont really think id need to bridge it . I think in mono mode its rated at 800watt into 16 ohms.
Daniel
so what would be suitable for a inverter on one channel? a simple op amp circuit? Am I correct in thinking you could not reverse the output into one channel so that signal out goes to ground in and ground out goes to signal in ? This would destroy the source by putting its output direclt to ground, right?
id make my own op amp box of tricks, with one mono signal being buffered then split one into an invetering buffer op amp (1x gain) and one non inverting so that they share a common ground and both signals or the same amplitude
this would drive both sides of the stereo amplifier having one side of the amp inverted, when connected to a load on both the live outputs, on paper will give you 4x the initial stated power, never works in practice, normaly due to the current drain on the trannies being in excess of the specs, (amps you buy in shops normaly use the cheapest trannies and use them to their max specs). check the transformer on the amp that i can take the current drain, most common stereo amps cant take it, if they cant, then you could add some large power caps to the supply to provide instant power for heavy bass.
also the voltage rails of the amp normaly drop dramaticaly when in bridge mode because of the large load applied.....
dont ever try and bridge an amp into 4ohms unless the amp is designed to be bridged (bad experience :S)
is it worth it?
build an amp yourself and make it to specs you know can be "over clocked"
this would drive both sides of the stereo amplifier having one side of the amp inverted, when connected to a load on both the live outputs, on paper will give you 4x the initial stated power, never works in practice, normaly due to the current drain on the trannies being in excess of the specs, (amps you buy in shops normaly use the cheapest trannies and use them to their max specs). check the transformer on the amp that i can take the current drain, most common stereo amps cant take it, if they cant, then you could add some large power caps to the supply to provide instant power for heavy bass.
also the voltage rails of the amp normaly drop dramaticaly when in bridge mode because of the large load applied.....
dont ever try and bridge an amp into 4ohms unless the amp is designed to be bridged
(bad experience :S)is it worth it?
build an amp yourself and make it to specs you know can be "over clocked"
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