I recently came across balanced headphone driving (better known as amp bridging) and just don't understand how this will make it sound better.
I understand how Balanced line transmission can cancel out interference induced to the cable using a Differential receiver.
but a headphone with a max cable length of maybe 5 meters?
I understand how Balanced line transmission can cancel out interference induced to the cable using a Differential receiver.
but a headphone with a max cable length of maybe 5 meters?
IMO it won't but it shouldn't make it worse either. You will have to convert your 3 wire system to a 4 wire to use bridge amps. I don't understand why anyone would bother with this.Bridge amps are usually used to increase power (more Voltage) on the cheap. Headphones require so little power this wouldn't be an issue.
G²
balanced and bridged are 2 different things; a balanced amp is bridged, but a bridged amp does not have to be balanced. for me its more about continuing a balanced signal path all the way to the end. most (ALL IMO) the top performing dac chips are balanced, it helps performance there with VERY short distances involved and its got nothing to do with power; what makes you think it all of a sudden becomes meaningless when talking about the headphones?
try it, you might like it
crosstalk is lower, some aspects of noise and distortion are lower and for me its most definitely subjectively better also
try it, you might like it
crosstalk is lower, some aspects of noise and distortion are lower and for me its most definitely subjectively better also
Last edited:
in principle bridged drive will cause even order distortion cancellation if the the 2 sides match well
some higher Z headphones need more drive V than can be had with common op amps - so doubling your Vswing can be useful for some
but there does seem to be unwarrated high expectations for "balanced" bridge output amps for many headphones
there are very few "true diferential in/out" amplifiers, Gilmore's "dyna-mid", ESL amps - most just use 2 separate amps
some higher Z headphones need more drive V than can be had with common op amps - so doubling your Vswing can be useful for some
but there does seem to be unwarrated high expectations for "balanced" bridge output amps for many headphones
there are very few "true diferential in/out" amplifiers, Gilmore's "dyna-mid", ESL amps - most just use 2 separate amps
Last edited:
I see, its so that the 2 channels are completely separated so that signals that may have gotten in the common ground does not affect the output right?
thats one aspect yes, the shared return is avoided (which contains ALL of the return signals, not just some that might have 'made it in', do not think of ground as some place residual signal dribbles into) noise, distortion, crosstalk, any error that is common to both phases of a channel but isnt inverted like the signal is, is deleted to a large extent
Balanced outputs to headphones in theory would have a cancellation of common mode junk, but consider using the amplifier to combine the phases and output unbalanced because obviously a high precision circuit is going to do a better job at that that than a voicecoil pushing a cone that was tuned for unbalanced drive. There is in theory also an advantage with balanced output in that the drivers are floating and not connected to a potentially dirty ground, especially if you are using a high speed sigma-delta DAC chip as a source (note that prior to sigma-delta, dac chips didn't have balanced output). So I can see the merit in Qsup's recommendation to leave balanced all the way to the headphones with a modern setup..
But keep in mind the output impedance comes into play because the headphone load to the amp is halved. In other words if you have 32 ohm headphones in balanced they are actually a 16 ohm load to the balanced output amplifier.
Where balanced output has really helped is with opamp gain stages in headphone amps, they generally top out at 7Vrms max swing before that nasty spike in thd vs Vrms. So balanced out gives you double that swing depending on the buffer's current handling.
So with a modern mid-level level setup with a DAC like the ES9018 and modern amp, its something worth looking at. The digital volume control really helps with a balanced setup because 4 -signal attentuation in analog is troublesome and expensive.
But if you are into classic multi-bit DAC and tube amps balanced becomes more trouble than worth.
So you really need to decide what system you like and what headphones you like before you make the decision to re-wire all your headphones for balanced. You can make a balanced to 1/4" headphone plug adapter to switch between amps, but all this costs money and time.
But keep in mind the output impedance comes into play because the headphone load to the amp is halved. In other words if you have 32 ohm headphones in balanced they are actually a 16 ohm load to the balanced output amplifier.
Where balanced output has really helped is with opamp gain stages in headphone amps, they generally top out at 7Vrms max swing before that nasty spike in thd vs Vrms. So balanced out gives you double that swing depending on the buffer's current handling.
So with a modern mid-level level setup with a DAC like the ES9018 and modern amp, its something worth looking at. The digital volume control really helps with a balanced setup because 4 -signal attentuation in analog is troublesome and expensive.
But if you are into classic multi-bit DAC and tube amps balanced becomes more trouble than worth.
So you really need to decide what system you like and what headphones you like before you make the decision to re-wire all your headphones for balanced. You can make a balanced to 1/4" headphone plug adapter to switch between amps, but all this costs money and time.
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.