I've been considering the merits of dual mono & differential drive (balanced/XLR) for driving high impedance, high resolution headphones.
Both offer independent control over each driver (left does not interact with right)
Balanced offers double the voltage with no need for a gain stage & prevents interference.
Dual mono is simpler
Assuming interference & output level is not an issue, which would provide the best performance?
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Both offer independent control over each driver (left does not interact with right)
Balanced offers double the voltage with no need for a gain stage & prevents interference.
Dual mono is simpler
Assuming interference & output level is not an issue, which would provide the best performance?
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BTL means twice the power into twice the load impedance - each amplifier sees half the load impedance. Shouldn't be too much of an issue if the headphones are high-impedance to begin with though. In any case, BTL is a proven way of getting more output when you are supply-voltage-limited.
In a fully differential amp, even-order harmonics tend to cancel. So do power supply related effects, which appear as common mode.
BTL obviously means higher parts count, with the expected statistical effect on robustness.
Dual mono mainly differs from a standard amp in ground routing.
What sort of inputs are you planning on implementing? If you have a balanced input anyway, a fully balanced amplifier topology seems tempting. It's not necessary though, as you can also use a main amplifier with single-ended output in lieu of an opamp in the balanced line receiver (since they usually tend to be opamp type amplifiers with differential input anyway).
Balanced amps do not necessarily always have 6 dB more gain (and neither does that always mean you can do away with a gain stage). Those comprised of combined (single-ended) non-inverting and inverting amplifiers do, but they are not entirely ideal since common-mode output impedance is still low. (Not like it matters much in most cases, unlike on the input side, but still.)
In a fully differential amp, even-order harmonics tend to cancel. So do power supply related effects, which appear as common mode.
BTL obviously means higher parts count, with the expected statistical effect on robustness.
Dual mono mainly differs from a standard amp in ground routing.
What sort of inputs are you planning on implementing? If you have a balanced input anyway, a fully balanced amplifier topology seems tempting. It's not necessary though, as you can also use a main amplifier with single-ended output in lieu of an opamp in the balanced line receiver (since they usually tend to be opamp type amplifiers with differential input anyway).
Balanced amps do not necessarily always have 6 dB more gain (and neither does that always mean you can do away with a gain stage). Those comprised of combined (single-ended) non-inverting and inverting amplifiers do, but they are not entirely ideal since common-mode output impedance is still low. (Not like it matters much in most cases, unlike on the input side, but still.)
If you don't need the extra drive capabilities, (BTL yada yada), I doubt if you'll see much improvement by going balanced. You really need that for low level and/or high impedance signals - microphones et. al. A (relatively) high signal level low output impedance source like a headphone amp or power amp will kill anything the cables might pick up.
Btw. are you planning on modifying the headphones also? Haven't seen headphones with balanced inputs, but I suppose there must be a few out there.
Btw. are you planning on modifying the headphones also? Haven't seen headphones with balanced inputs, but I suppose there must be a few out there.
I have seen dozens of full size headphones and many dozens of the earbud style.
All had/have a trs style plug with a commoned return connection.
I think there are some special connectors that suit ultra slim equipment like mobile phones and such. But are these two separete left and right connectors, or do they also common the return connection?
3 connections (common return) means unbalanced, since the single jack serves both sides of the headphones (unless there are two such cables, one for each side).
Balanced headphones would have 4 connections (L-, L+, R-, R+) plus optional shield. Like I said, never seen any like that. I have seen stereo microphones with 5 pin round DIN connectors, though.
Ok, I stand corrected, they do exist, and a lot of people swear by them.
https://www.headphone.com/pages/balanced-headphones-guide
A lot of people (self included) think this is overkill for headphones, but I'll keep an open mind for now.
Quote from http://www.head-fi.org/t/518138/what-are-balanced-headphones
https://www.headphone.com/pages/balanced-headphones-guide
A lot of people (self included) think this is overkill for headphones, but I'll keep an open mind for now.
Quote from http://www.head-fi.org/t/518138/what-are-balanced-headphones
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The headphone world has come far quickly. High end DACs feature XLR & SE out.
And 4 pin XLR is the best method of utilising balanced connections to the 'phone.
However, I'm from old school thinking where dual mono amps in SE configuration were the ultimate. And balanced XLR were for driving long runs.
Since most headphones don't actually need more than 2Vrms for typical loud listening level, I want to build a high end discrete buffer.
My DAC has both outputs so I'm trying to identify the merits of balanced over SE or vice versa.
My 'phones are high impedance Sennheiser HD800 (350 ohm nominal, peak at ~600 ohm)
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And 4 pin XLR is the best method of utilising balanced connections to the 'phone.
However, I'm from old school thinking where dual mono amps in SE configuration were the ultimate. And balanced XLR were for driving long runs.
Since most headphones don't actually need more than 2Vrms for typical loud listening level, I want to build a high end discrete buffer.
My DAC has both outputs so I'm trying to identify the merits of balanced over SE or vice versa.
My 'phones are high impedance Sennheiser HD800 (350 ohm nominal, peak at ~600 ohm)
Android powered
If your headphones are wired for balanced operation (or you are prepared to redo the wiring yourself), balanced seems to be the way to go. However, be aware that the balanced configuration must extend all the way to the headphone drivers; no good just changing the jacks.
Where you'll get balanced cables suitable for headphones, I don't know. You could try running two stereo headphone cables - one for each side.
Where you'll get balanced cables suitable for headphones, I don't know. You could try running two stereo headphone cables - one for each side.
There is no benefit to balanced headphone drive unless you are supply voltage limited as mentioned before. If you drive the headphones with a 0 ohm output impedance you are already have balanced impedances, and headphones are inherently differential already.
You'll most likely get increased distortion as each amplifier will see half the load impedance.
It's all a clever "scam" that was started by a certain headphone amp manufacturer to get around supply voltage limitations with op-amps and also charge twice as much at the same time.
You'll most likely get increased distortion as each amplifier will see half the load impedance.
It's all a clever "scam" that was started by a certain headphone amp manufacturer to get around supply voltage limitations with op-amps and also charge twice as much at the same time.
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