[Pale Rider]

Ribbons aren’t really new comers as transducers and no new development is necessary. Comments relate more a seek for good combinations since those ribbons are used as headphones.
Speaking of tube amps, designs have for sure history and an interesting approach is to look at transformers with the correct ratio for the SR1a.

Is avoiding the interface box a relevant solution compared to a good synergy ?

I think you misunderstood my point. I know ribbons aren't new. I built and owned near-full-range ribbon systems decades ago. But a headphone like the SR1a might well spark amplifier development in much the same way that the Audez'e LCD-2 sparked Decware to refine its Taboo SET to drive specifically that and other planar headphones. Further, there will always be new amplifier developments, and some may happen specifically as a result of these cans.Think outside the box a little.

And in answer to your question, I would suggest that avoiding the interface box is itself one form of approaching "synergy," whatever that buzzword might mean to different people. The impressions and assessments by Jotunheim R testers is that yes, in fact, both removing the box and using different amplifiers produces audible differences.

 

[cladane]

Yes, for planars many manufacturers adapted their designs and looking at Audeze power needs thinking at the LCD4.
VIVA made on this point a noticeable coming with the Egoista.

Agree that as adaptations occurring soon it is what suggests me the possibility of specific output transformers for the SR1a, regarding tubes.

Audible differences in both cases, that’s not to be discussed, in my mind don’t necessarily bring pertinence. Speaking of SQ in the end.
Actually wondering if removing the box will bring better SQ than pairing very well the SR1a ?
Questions like comments arguing about using a Sub for bass presence ?

Those headphones introduces like MySphere a changement in listening approach or music presentation and perception.

 

[Pale Rider]

Not sure I understand what you mean by this:

Audible differences in both cases, that’s not to be discussed, in my mind don’t necessarily bring pertinence. Speaking of SQ in the end.

What else would an assessment of SQ be—good or bad—except an audible difference? If one swapped an amp, or removed a buffer box, and it made zero difference, i.e., no audible difference, then there isn't much point in making the swap. But the information of "no difference" is both relevant and useful, i.e., "pertinent." But if there is a difference, that is also pertinent. Now, for any given individual, the change may or may not be an improvement in SQ. For example, one person's expansive sound stage is another's over bloat. One person's detail is another's over-brightness. But without the information of a difference, how does one even get to the stage of "pertinence"?

Actually wondering if removing the box will bring better SQ than pairing very well the SR1a ?

Seems to me the obvious answer is that it could be either, because they are two different things. And we won't know until people try, and then report their impressions. And no one will know whether they like any of the changes without comparing them against a known reference of their own.

 

[Aleksandar R.]

The interface box can surely be omitted, as long as the EQ curve for SR1a is done elsewhere (at amp input, for example).

Here is one way of doing it, for RCA inputs:

"In" is where the source is plugged in and "Out" goes to amp's input.

Here is the input impedance of this little circuit:

It is about 4.2kOhms above 2k.

If one would like to try transformers, the load will be headphones + cable, which is 0.39-0.40 Ohms. At least for the cable that we ship out with the headphones.
If any other cable is used, the new transformer ratio has to be made and passive EQ around the transformer won't work correctly.
Because of that, we decided not to use transformers as the interface.
Resistor interface box that we supply is far less sensitive to cable impedance and EQ is accurate within 0.5 dB for cables from 0.1 to 0.9 Ohms and amplifier loading change is irrelevant for the amp.

However, when you build the amp dedicated to drive the SR1a, you will use line-level EQ, not at the power output, and you may decide to make different output taps for different cable resistance to cover several possibilities for the end user.

 

[Pale Rider]

Superb info. Thanks @Aleksandar R. !

 

[johnjen]

You are speaking of conventional knowledge regarding transformers.

Looking carefully at the picture, you can see that Pierre, the French reseller visiting VIVA facility in Italy with us, listens to these SR1a directly connected to the output of the tube amp without trouble.

Yes that is true, and yes you can connect up a near dead short to a xfmr and it will not blow up nor fail.
However if we are looking for a suitably high quality signal source it leaves much to be desired.

Namely the 'reflected load' back to the tubes means the tubes are no longer operating in their designed 'sweet spot' from an impedance pov.
This in turn means the amount of distortion from the output is no longer 'in spec'.
And it also means that while they will play, many of the other operational parameters (dynamic range, headroom, FR, s/n, etc.) are also no longer 'in spec' either.

And from my perspective if I'm using a SotA set of HP's and use 'compromised' signal source(s) (no matter the quality) that simply can't deliver the SQ that feeds the HP's well, I'd be seeking a 'better' solution.

And I have found that dialing in the impedance of the load that the output 'sees', especially in a tube amp, is a necessity if the optimal SQ from the interaction between the load and output stage of the amp is to be realized.

These HP's are at a disadvantage when it pertains to this parameter of load matching, thus the need for an 'interface box' to bridge the gap.
And driving a near dead short is problematic, no matter how you want to look at it.

But there is little chance of damage to a tube amp, with output xfmrs, or a lack of lighting up the SR-1a's, rather it's more of a situation of how to obtain optimal SQ, which would be my primary consideration.

JJ

 

[cladane]

Useful details @Aleksandar R.
Kind to bring material to this discussion around the interface box.

About pertinence, @Pale Rider ,of course need is that between going through the box or going direct ‘audible differences’ must occur. I was meaning that, if SQ isn’t better going direct, it would be more pertinent to remain with the box in a system with good synergy.
About reporting Impressions, the Jotunheim R solution wouldn’t be an inclination because of the very good financial ratio against the pricy amps listed in the comments ? Just wondering.

@johnjen, Here Aleksandar gives clues about how going direct could be done if someone thinks that the box with so many components on the signal path can impact the SQ of the SR1a ?

Quite a lot of questioning about how to optimize the setup around these headphones.

 

[johnjen]

snip
@johnjen, Here Aleksandar gives clues about how going direct could be done if someone thinks that the box with so many components on the signal path can impact the SQ of the SR1a ?

Quite a lot of questioning about how to optimize the setup around these headphones.

My comments are more aimed at how the SR-1A's low impedance can be a problem in and of itself and how using a xfmr output from a tube power amp will not provide optimized SQ at such low Ω's.

And looking at @Aleksandar R.'s graph is confusing to me.
The vertcal axis on the right side is labeled as phase yet is referred to as ohms, yet at the very bottom of the graph the values go negative…
And throwing an RC network at the input of the amp confuses me still further, as this implies that adding non-linearity to the mid bass and lower is needed for these HP's?
Like I said I'm confused…

JJ

 

[Kelowna]

Although I'm no longer in retail sales, I'm building @Pale Rider a custom, direct to SR1a system, I'm confident will be good enough to be his new reference. It will be an all in 1 box with direct connection to the headphone cable. To keep the signal path as clean as possible, 100% lossless 64 bit floating post DSP in the Roon media player will be used for the EQ curve. A long overdue replacement for the setup in this review:

https://www.head-fi.org/threads/pos...ne-rig-focal-utopia-mivera-superstack.838570/

I can't wait to hear how it stacks up against the MSB Select 2/ Jot R combo, connected together with his Belden Iconoclast interconnects.

 

[thomaskong78]

I am playing Sr1a with two 18 inch Scaena sealed subwoofer(120lb each , Kevlar/Carbon composite cones) which I got last Friday.

It is fun with subass rumble to real 16hz in the background.

But the subwoofers work better with my Lansche 4.1 speaker like magic with clean and deep bass and enormous dynamics and wider deeper soundstage.

https://photos.google.com/share/AF1...?key=VjN1SHRiUWYxUGd0dk5qWTVQOEJNNXdMaEZ0RGZB

My listening room used to be tidy about 18 months ago

https://photos.google.com/share/AF1...?key=VjN1SHRiUWYxUGd0dk5qWTVQOEJNNXdMaEZ0RGZB

But now it is a mess with several isolation transformers and cable for Sr1a headphone.

Even with such mess, I enjoy the sound of my 2 channel system and Sr1a, Stax 009s headphones.

 

[Aleksandar R.]

My comments are more aimed at how the SR-1A's low impedance can be a problem in and of itself and how using a xfmr output from a tube power amp will not provide optimized SQ at such low Ω's.

And looking at @Aleksandar R.'s graph is confusing to me.
The vertcal axis on the right side is labeled as phase yet is referred to as ohms, yet at the very bottom of the graph the values go negative…
And throwing an RC network at the input of the amp confuses me still further, as this implies that adding non-linearity to the mid bass and lower is needed for these HP's?
Like I said I'm confused…

JJ

It's just a graph configuration that I could have set any which way...disregard the negative axis for impedance.

These are open-baffle and have 6db rolloff below 2k, which is not completely cancelled out by the proximity of the ear to one side of the dipole, therefore the EQ has to be implemented, that starts from ~200Hz and end at ~2k, with -4.5 db step.
This response is built-in in the Interface box, so if you plan to loose it, make the EQ elsewhere.
All this has been explained in detail somewhere at 60-ish page of this thread, but it is better to search my posts here and find what has been written about it.

 

[Aleksandar R.]

The transformer for a tube amp is not a big problem.
You keep the primary at the same number of turns as you would for a 4 or 8 Ohms secondary. In correctly sized transformers, the primary will use up one half of the core window area. The other half of the window area will be filled-up with secondary.
This time you have a 0.4 Ohms as a load at the secondary, which needs 3.16 times less turns than 4 Ohm load secondary, but you will use 3.16 times greater wire diameter to fill up the window, so your losses are proportionally the same.
If there would be layout issues, just increase the core to the next larger size.

Of course, use as many layers as possible and other "tricks" to control stray inductance and parasitic capacitance to make it wideband, just as you would with any other tube output transformer.

 

[johnjen]

It's just a graph configuration that I could have set any which way...disregard the negative axis for impedance.

These are open-baffle and have 6db rolloff below 2k, which is not completely cancelled out by the proximity of the ear to one side of the dipole, therefore the EQ has to be implemented, that starts from ~200Hz and end at ~2k, with -4.5 db step.
This response is built-in in the Interface box, so if you plan to loose it, make the EQ elsewhere.
All this has been explained in detail somewhere at 60-ish page of this thread, but it is better to search my posts here and find what has been written about it.

Thanks for that reply.
It makes much more sense now that I understand the graph.
And I will search for your posts to better understand the technical merits of this design.

JJ

 

[thomaskong78]

HEDD Audio HEDDphone - Official Thread

Someone just compared HEDDphone with Sr1a.

He said Sr1a beat Heddphone hand down.

I enjoy sweet voice of Karen Carpenter through Sr1a.

Sr1a is my end game headphone with fast, open and balanced sound.

Abyss TC could give more powerful and deep bass than Sr1a.

But if I want powerful bass, I would play my 2 channel system augmented by two 18 inch Scaena subwoofers.

 

[GuyForkes]

HEDD Audio HEDDphone - Official Thread

Someone just compared HEDDphone with Sr1a.

He said Sr1a beat Heddphone hand down.

I also gave my impressions on them here:
https://www.head-fi.org/threads/hed...h-amt-technology.906270/page-50#post-15419615