Simple Headphone Amp

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MikeHunt79

MikeHunt79

Member
Joined 2003
Nico Ras said:
Hi Mike,

Just try one of the earlier recordings 70's & 90's and even some recent recordings, especially on electronically generated music. The sound is so spatial it makes your eyes water. I read somewhere that to wide stereo have a psychological side effects and the reason you suffer fatigue is because the brain copes badly with sound that only exist in one ear, it is not natural that sound does not spill around your head.

I will try and locate the web-site, it is really very interesting, and it works.

I think that you may be suffering from this effect rather than anything else. Try it, you may just not have to build another amp.

Kind regards

Nico
Click to expand...
Out of all my headphones, I find this most noticable on my Alessandro MS1's. It only takes a short time to get fatigue, and I think this is due to the bright nature of the sound. I do use a crossfeed DSP (bs2b) plugin for foobar2000, which I find this eliminates fatigue, and has the advantage of being configurable - I can control the mount of HF rolloff, etc.
Nico Ras said:
Would anyone be kind enough to explain to me what the benefits are if any why one would want to push the ground signal through an amp as well.
Click to expand...
On paper, balanced eliminates ground loops (which isn't really much of a problem in the headphone world), eliminates crosstalk and has a lower noise floor... weather this leads to a better overall sound id debatable.

To me balanced sounds better than single ended - but that might be because I'm using portable amps, and I'm driving the amps less hard under a balanced setup. Hopefully when I get the parts and time to try your amp design, I'll see how balanced compares to single ended, as single ended could end up sounding better than balanced...
 
G

Gordy

Disabled Account
Joined 2006
MikeHunt79 said:

On paper, balanced eliminates ground loops (which isn't really much of a problem in the headphone world), eliminates crosstalk and has a lower noise floor... weather this leads to a better overall sound id debatable.

To me balanced sounds better than single ended

Click to expand...


Now I understand your perspective. You are very much confusing balanced with bridged. In an audio system context, *Balanced* refers mainly to interconnection, whereas *Bridged* refers mainly to amp output stages (although the HeadRoom adverts have served to confuse people). Bridged means that the output is bridged between two active outputs, instead of between an active output and 'ground'.

When you say *single ended* in relation to amp output stages I think that you mean simply *non-bridged* outputs. (Non-bridged outputs can be single ended, but they can also be push-pull. It gets a tad confusing because bridged outputs can also utilise single-ended output stages on each side of the bridge!).

Designing a bridged output involves a lot of extra circuitry... the extra output plus the signal inverter for it, plus changes to the power supply (all x2 for stereo). All of that creates it's own problems, so is perhaps only worth it if you really need the extra voltage swing provided by a bridged output topology. In my small world the smart money is on non-bridged dual monos.

Still, it's your money and your head, so experiment and enjoy.
 
Nico Ras

Nico Ras

Member
Joined 2005
MikeHunt79 said:

On paper, balanced eliminates ground loops (which isn't really much of a problem in the headphone world), eliminates crosstalk and has a lower noise floor... weather this leads to a better overall sound id debatable.

To me balanced sounds better than single ended - but that might be because I'm using portable amps, and I'm driving the amps less hard under a balanced setup. Hopefully when I get the parts and time to try your amp design, I'll see how balanced compares to single ended, as single ended could end up sounding better than balanced...
Click to expand...


Mike,

I m intrigued by this balanced headphone amplifier idea. Kindly post a typical circuit so both Gordy and I can be enlightened. I don't think either of us understand this concept.

Kindest regards

Nico
 
MikeHunt79

MikeHunt79

Member
Joined 2003
Nico Ras said:



Mike,

I m intrigued by this balanced headphone amplifier idea. Kindly post a typical circuit so both Gordy and I can be enlightened. I don't think either of us understand this concept.

Kindest regards

Nico
Click to expand...
Ok, my setup only works due to having a balanced source...

I'll try to describe and post a quick diagram....

source = 1212m balanced analogue out, from 1/4" trs jacks, thru a 4 gang pot (volume control) to 3.5mm jack connectors, to the cmoy amps.

Maybe a diagram could be better... se the attached diagram

H=Hot C=Cold G=Ground L=left R=Right I've left out the pot, but this works without the pot also.... Also, both Cmoy's have volume pots, I used a scope to get an even power output for left and right...

Gordy: I'm now more confused than ever... I'm pretty sure this isn't a bridged setup, but I may have things mixed up here...
 

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Nico Ras

Nico Ras

Member
Joined 2005
MikeHunt79 said:

Ok, my setup only works due to having a balanced source...

I'll try to describe and post a quick diagram....

source = 1212m balanced analogue out, from 1/4" trs jacks, thru a 4 gang pot (volume control) to 3.5mm jack connectors, to the cmoy amps.

Maybe a diagram could be better... se the attached diagram

H=Hot C=Cold G=Ground L=left R=Right I've left out the pot, but this works without the pot also.... Also, both Cmoy's have volume pots, I used a scope to get an even power output for left and right...

Gordy: I'm now more confused than ever... I'm pretty sure this isn't a bridged setup, but I may have things mixed up here...
Click to expand...

Hi Mike,

looking at your diagram, I do not believe that it is actually balanced but that you make use of the +- balanced output of the 1212m to drive the two amps differentially and the result is actually bridged. But one could also argue balanced I guess as the common mode rejection should be better than common ground.

You could do exactly the same with the headphone amp described here it should sound great.
 
MikeHunt79

MikeHunt79

Member
Joined 2003
Nico Ras said:


Hi Mike,

looking at your diagram, I do not believe that it is actually balanced but that you make use of the +- balanced output of the 1212m to drive the two amps differentially and the result is actually bridged. But one could also argue balanced I guess as the common mode rejection should be better than common ground.

You could do exactly the same with the headphone amp described here it should sound great.
Click to expand...


Ahh, now it makes sense. Thanks for clearing this up. :) I've got a few other projects to finish first :)smash: ), but I'm really looking forward to trying this amp. :)
 
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