[rickyleelee]

   
Nice spot!
 
But no-one has asked the most important question.
 
Hint: we are on Head-Fi after all.

 
 
Is it something to do with headphones?

 

[iFi audio]

   
 
Is it something to do with headphones?

 
Hi,
 
Very warm for sure.
 
No-one has asked where is the headphone section?

 

[rickyleelee]

mmmm.......where is the headphone section and what the vital statistics? am sure not only me is interested!

 

[Wildcatsare1]

True, on the Boards shown, there doesn't appear to be a headphone "out", where do you connect them Mr. iFi?

 

[technobear]

Sorry, I thought it had already been mentioned that the headphone sound comes from those six funny glassy silvery looking things.

It does beg one question though.

If the output transformers are optimised for modern current-hungry 4 - 8 ohm loudspeakers, is the Retro 50 limited to driving low impedance headphones? Will using a 600 ohm headphone affect the performance?

 

[Wildcatsare1]

Not the sound, the HP out, the physical connection, I do hope the sound comes from those lovely light bulbs, that's the point. No? Is there a series resistor of sorts placed between the tube amp and the HP connection/jack to protect the amp?

 

[Wildcatsare1]

Sorry, I do hope the sound comes from the lovely light bulbs. Is there a set of resistors placed between the amp and the HP connection to protect the amp? It will be single ended, as you have said, but you will need to protect the amp from odd loads.

Whoops, double post, my bad!

 

[iFi audio]

Headphone section - classic approach with new technology addition

 
The headphone section is actually as pure as can be.
 
That is, both the 6.3 and 3.5 utilise only have a minimal impedance/level matching and Headphone Protection Network and then it is tapped to the all tube/valve amplifier.
 
So there is no separate headphone section at all to speak of. Instead the tube amplifier makes one able to listen on speakers and headphones with all the magic of tubes.  
 
But often tube magic comes at a price - noise.
 
Take this AP2 test for noise that is typical for most tube amplifiers. This chart means having noise in your ears all the time. And this noise is a fact of life of most tube amplifiers (whether they have Headphone Outputs or not, but exacerbated if there is a headphome amplifier section).
 

 
But as with just about most tube amplifiers, this great sound is offset by a residual noisy background all the while during listening.
 
The peaks are the noise spikes so one can hear this. But with the Retro, there is none of this going on. So IEMs or On Ears or indeed speakers, the background is silent.
 

 

Note: The y and x axis are scaled just about the same so one can compare these two graphs properly.
 
 
Further, while the Retro Stereo 50 driving speakers will operate in Class AB at high power (> around halve power), driving headphones it never leaves Class A. So the Retro is actually not just a Speaker Amplifier, but also a pretty impressive Class A Tube DAC/Amp for Headphones.
 
So for smarty pants - yes, connect the headphones to the Retro Stereo 50 and you are breaking-in the main amplifier - you do not have to attach speakers (but there is a benefit to running-in the Amplifier with speakers attached, let us tell you a secret about this in another post....)

 

[iFi audio]

Sorry, I thought it had already been mentioned that the headphone sound comes from those six funny glassy silvery looking things.

It does beg one question though.

If the output transformers are optimised for modern current-hungry 4 - 8 ohm loudspeakers, is the Retro 50 limited to driving low impedance headphones? Will using a 600 ohm headphone affect the performance?

 
Very good.
 
The matching network slightly attenuates the signal from the Amplifier and also makes sure the output transformer is correctly loaded (tube amplifiers shouldnot run open circuit, it can cause damage to the output transformers).
 
The 6.3mm output is only minimlly attenuated, it can drive most headphones equal to the iDSD micro. The 3.5mm is attenuated by around 15dB, to accomodate very sensitive headphones (IEM's etc) better.
 
The upshot of all this is simple - using 600 Ohm headphones with low efficiency is fine, as is using 16 Ohm headphones with high efficiency.
 

 

[EVOLVIST]

Wow!

 

[Wildcatsare1]

Very nice, when can we purchase a Retro in the States?

Can you listen to speakers and headphones at the same time, silly question, but you never know?

 

[iFi audio]

Very nice, when can we purchase a Retro in the States?

Can you listen to speakers and headphones at the same time, silly question, but you never know?

 
Hi,
 
Personal question so no need to answer on a public forum. How many ears do you have?

 
Seriously, no, connecting headphones switches the Speakers off and when engaged switches the 3D Holographic Sound system from Speaker to Headphone mode.
 
So the 3D Holographic automatically switches between Speaker or Headphones (as they are almost polar opposities).
 
But you can simultaneously connect to the 3.5mm and 6.3mm and listen on two sets of headphones. As they are nearly the same level, the one volume control means both are at similar levels.

 

[maricius]

So for smarty pants - yes, connect the headphones to the Retro Stereo 50 and you are breaking-in the main amplifier - you do not have to attach speakers (but there is a benefit to running-in the Amplifier with speakers attached, let us tell you a secret about this in another post....)

 
I bet the benefit is that the speakers will be broken in as well. Amazing stuff. HAHAHAHA 

 

[BillsonChang007]

wait. So the headphone and speaker shares the same amplifier as the speakers but burning in with speakers has different benefit... @.@ I am kinda confused here sorry 

 

[rmullins08]

Very nice, when can we purchase a Retro in the States?

 
Already for sale at Musicdirect.com