Balanced Headphone Amplifiers
 

Everything you probably want to know about balanced headphones and amplifiers. :D

http://violectric-usa.com/download/B...0Explained.pdf

Some further reading on balanced. This may be a bit easier of a read. https://www.headphone.com/pages/bala...adphones-guide

Hmmm
 

....and here comes captain bringdown :)

https://benchmarkmedia.com/blogs/app...uts-are-better

What I did not like about that article from Benchmark is too many assumptions of making the "worst case scenario" that the fully balanced headphone amplifiers are necessarily worse because of higher output impedance, more noise and distortion because of dual amplification per channel. While it is true that "some" not so well engineered examples could be indeed worse, there are plenty of examples of a well designed, fully balanced products that deliver. I've seen plenty of balanced headphone amplifiers that are very low output impedance and are not noisy by any stretch of imagination. It is Benchmark's choice to offer SE and not balanced and that's their business but making worst case scenario assumptions is not fair to other designers who believe they can make a great balanced design and actually are successful at it. My Bryston BHA-1 offers both SE and Balanced as a choice to the end user. I like that. :yes:

Whether balanced in headphone use is actually necessary or not is still a very much debatable subject but there is one fact that remains pretty obvious, not all headphone amps are created equal and not all of them drive various headphones to perfection. :D

I've come across designers who believe that balanced circuitry does not belong on high end audio period (not even talking about headphones here) and that single ended sounds clearly better because balanced circuitry introduced extra circuitry and op amps, etc... Yes, the gear sounded great in single ended if you were lucky enough to get away with all single ended in your rack and not have noise. At the same time, we all know that's not a fact but an opinion of that particular designer and there are plenty of high end audio products that also sound great while implementing balanced connections between components. :D

One word....Mjolnir.

:D

Also on my radar Stephen. :yes: One headphone amp does not exclude the other. :D I like the 6SN7 tube in general from previous experience. :music:

Balanced Headphone Amplifiers
 

Yep - the Benchmark white paper misses a lot of critical points. I don't agree with most of it. But I also think he makes some good points.

The best sound I've ever heard from headphones was a balanced DAC into a fully balanced headphone amp.

So let me unpack this.

Headphones are balanced by nature - TRUE. They don't know if they are being driven by a single ended or balanced amp.

Having a common return will cause some crosstalk. TRUE.

So run a 4 wire system from the amp to the phones and then it's macht nicht.

What Siau misses is that having a truly balanced amplifier driving the 'phones will cancel out the distortion in the two identical amps that are driving the 'phones differentially. Done correctly, balanced drive dramatically reduces distortion.

Siau's claim that the noise goes up with balanced is specious and without merit.

The signal voltage doubles, but the uncorrelated noise does not, so the S/N actually improves by 3 dB.

Balanced reduces noise induced in the cables - FALSE. Since the headphones themselves are balanced, there is no difference between balanced and unbalanced cables. Any induced noise will be cancelled at the drivers.

Am I stirring the pot? You decide. But I don't have any economic interest in the discussion, whereas the authors of all articles posted so far definitely do. :)

Well you are probably referring to the original article in my first post by Violectric? So then we should of course compare side by side with Benchmark? :yes:

One is a dedicated headphone amp, the other is a DAC with a headphone out?

Benchmark chose to package their product as a DAC to include a SE headphone out.

Violectric decided to do a balls to the wall headphone amp with both SE and Balanced and a DAC module if needed or wanted.

Both products over $2k. So probably will be used with rather serious headphones?

Right... Let's take an Audeze just as an example.

Audeze LCD-4 requires 1-4W and is 200 ohm impedance.

Benchmark puts out 1.2w into 30 ohms and much less into 200. :tears:

Violectric puts out 2.8w into 32 ohms, 4.2W into 50 ohms and whopping 5.6W into 100 ohms.

Violectric V281 also specs out at

Crosstalk:
-105 dB (1 kHz) / -103 dB (15 kHz)

Output impedance:
< 0.1 Ohm unbal. / < 0.2 Ohm bal

Dynamic range:
> 129 dB (A-wtd)

Noise:
< -95 dBu (A-wtd)


I'd say with specs like that Violectric is a serious BALANCED headphone amp. :yes: What was Benchmark saying again? :D

So yep, I have a Benchmark HGC3. What their specs say is that I will have to buy a dedicated headphone amp because they don't have the juice to drive the 200 ohm LCD-4's that I just bought!

All the balanced/unbalanced stuff doesn't matter if you don't have the juice!

It will drive it just fine. No balanced cable upgrade to worry about either! ;)