The idea of a standalone dCS headphone amp is attractive but how would it be implemented as far as connectivity is concerned?
I don’t envisage it as being wholly separate to the dCS DAC range but as something that expands upon it ( more or less offering similar compatibility as the headphone option in Bartok). To do this it would connect to the analogue outputs of the DAC rather than via a tape circuit output on a preamp. But either the XLR or RCA output ( or both) on the DAC is/are already occupied by the connection to preamp or power amp. So either one may have to accept that one’s preferred connection is not available ( e.g. must use RCA instead of XLR) or be prepared to rewire every time one changes from speaker to headphone.
I guess there could be a loopthrough option on the headphone amp but that adds connections which I would not be enthusiastic about.
All random thoughts of course as , for all we know, no such product is being developed by dCS in any case.
Edit. If the reason is to add Expanse then as I assume this applies a dsp function then the data has to remain in digital form which makes the standalone headamp… a Bartok as it would need to contain a DAC for subsequent analogue output to the headphones.
That seems unfortunate given SPL’s location. I can order several Phonitor models here, including the 2, with return privileges. There is sometimes a wait of a few weeks, but nothing terrible.
Hmmm. I haven’t heard Expanse, but I’ve heard nothing but enthusiasm for it. I suppose one thing that Bartok could portend for the upper ends of the line is a headphone amp option for each dCS product tier. Now that I could really get behind.
Since Expanse is done completely in the digital domain, I’d assume dCS could theoretically roll it out across any of their platforms that have enough DSP headroom. I don’t think there’s any dependency on the Headphone Amp per se.
A future range of course. It would not be feasible physically or , I suspect, economical, to retrofit it to Rossini and Vivaldi. There isn’t the space in the chassis and it would require replacement of the front panels to provide the 1/4" and XLR sockets. The cost of those front panels from supplier to dCS is substantial and if one adds the conventional fivefold increase to reach shop price … !
Anup, I am glad that you used the thinking emoji to conclude. Succesful crossfeed circuits which include Expanse ( at the top end) are based around amplitude and phase behaviour. In turn the algorithms chosen may depend on their success upon known amplitude and phase characteristics of the analogue amplifier circuit that they feed. I also need to use as we just don’t know.
If the Expanse crossfade DSP is taking place in the FPGA and through the dCS DACs across the line-up, then a provision at the back panel could be an extra analog headphone-only line out (balanced XLR and unbalanced RCA), to be connected to a separate (dCS or non-dCS) headphone amp.
A dCS headphone amp would give the advantage of best adaptation between the two.
In go the Rossini, a Neukomm CDA126S DAC and an empty connection for my testbed.
Out it goes to my Neukomm PA18 monoblocks and two headphone amps (Highamp Sirius for STAX, Bryston BHA1).
The switch was custom built by Dodocus Audio-Umschalter. The switch is completely passive using high quality switching elements. The blue LED does not come from the switch.
Dodocus are very flexible and custom build switching equipment. They can also do remote controllable, relays based etc.
Now if all the DSP processing in the Bartok is done digitally it would seem easy to implement the same thing across the product range, as the Bartok has essentially the same board as Rossini.
I would vastly prefer to keep the headphone amp separately. Otherwise STAX and Co will not be able to use the feature.
Thanks Rudi, that looks like the perfect interface for using a separate headphone amp. But then we still need Rossini and Vivaldi to be able to output a normal line level, or an Expansed line level out. The Bartók puts Expanse only out from its headphone connections at the front.
As long as Expanse is purely digital, you could select off/on it like you do different filters. Should be doable via software.
I don’t assume you would want to listen to Expanse and Normal at the same time via two different outputs
So, by a switch in software/ Mosaic you either route a Expanse-modified line output signal, or a normal line level output signal, from the line level outputs at the back. These are connected to a switch box as you have indicated. The box outputs to either a headphone amp, or a stereo power amp, or 2 mono power amps.
This would also work with my Benchmark HPA4, without the switch box.
… except as Pete suggested, it’s possible the Expanse DSP algorithm has to take the built-in Amp section characteristics into consideration - we won’t know unless someone from dCS comments
(Speaking of which, if dCS does do that, I wonder if Expanse 2.0 on the Bartok could pre-compensate for any analog non-linearity in the Amp section… or maybe it already does that? ).
Thanks for posting that. This is precisely what I need in my headphone rack, or a version of it anyway. I’ve been using a nice Hattor passive pre, but it does more than I need it to. All I need is a quality switch. Inquiry sent.
as it would need to contain a DAC for subsequent analogue output to the headphones.
as we just don’t know.
