New Switch - Any suggestions

[torbenrick (A Dane living in Hamburg)]

@Anupc

very cheap external Switching PSUs near sensitive Audio kit especially because they’ll spew noise back into the AC mains.

Yes Buy a good SMPS (I use Mean Well AC-DC Medical desktop adaptor with 3 pin ) and than combine it with AUTH line filter EMD 503 or AUTH line filter EMX 506 (AUTH only cost around 100 EURO)

Torben

[glevethan (Gregg)]

@Anupc

If you check my posts related to Ethernet Switch Power Supplies, they’re in the context of Fiber Media Converts and the need to avoid using those very cheap external Switching PSUs near sensitive Audio kit especially because they’ll spew noise back into the AC mains.

I have been using fibre optic for a while with two Cisco 2960’s and Cisco fibre converters. Anything to worry about with the 2960’s internal power supplies?

[Phil (Phil Harris)]

Hi Gregg,

@glevethan

…particularly the dCS folk who actually design the equipment.

One of the things that I love about being at dCS is that EVERYONE that I interact with “at the office” has such passion for what dCS do and there is a real feeling of ownership of - and pride for - their particular bit of that.

That’s such a special thing to be a part of and so rare to be able to find nowadays…

[Lee (Lee Scoggins)]

Fair enough Anup but it can be a gray or fine line between objective areas and subjective areas. If I can get some data on the noise before and after the tesla coils then I will share it.

[T38.45]

@Lee

it made for quiter backgrounds and a sense of it being more open.

that is my finding here too. More air around the musicians and it is easier to follow the music when listening with lower volume. I do not know if there is something like a S/N ratio for switches

[TheFlash (Nigel of Reiki Audio)]

@torbenrick

Yes Buy a good SMPS (I use Mean Well AC-DC Medical desktop adaptor with 3 pin ) and than combine it with AUTH line filter EMD 503 or AUTH line filter EMX 506 (AUTH only cost around 100 EURO)

Torben

Are you against LPS?

[torbenrick (A Dane living in Hamburg)]

@TheFlash

Are you against LPS?

No, I am not against LPS, there is just no need to spend 700-1000 EURO on a PS. Back in the “old” days SMPS’s where quit noisy. But that have changed if you buy a good SMPS.

More and more audio suppliers are changing to SMPS, leaving LPS behind as a remedy of the past.

Torben

[TheFlash (Nigel of Reiki Audio)]

We disagree but I’m ok with that. Manufacturers use SMPS for many reasons.

[Anupc (Anup)]

@Lee

it can be a gray or fine line between objective areas and subjective areas. If I can get some data on the noise before and after the tesla coils then I will share it.

Generally w.r.t audio related kit I would say yes, but it’s not the same with data networking, there’s not much “gray” so to speak.

In any case, looking forward seeing any objective information from Ansuz

[Anupc (Anup)]

@glevethan

I have been using fibre optic for a while with two Cisco 2960’s and Cisco fibre converters. Anything to worry about with the 2960’s internal power supplies?

Gregg, nothing to worry about, the PSU in the 2960 is pretty good (and designed to be left on 24/7 for years).

The thing is, some folks seem to equate the Power Supply requirements in things like Amps/PreAmps with those in Ethernet Switches, when in fact they’re completely different.

Analog components need good/quiet PSUs because the output you hear is literally the wall-AC signal that’s been rectified, cleaned, and re-modulated (by the input analog signal).

Whereas with Ethernet transmission, the signals riding on Ethernet cables come from silicon chips which require only a basic clean 2.5V (or 1.8V) VCC DC, usually derived from regulated 12V and/or 5V PSUs. In the case of your Cisco 2960, IIRC, the PSU outputs 12V, and the motherboard does a DC-DC step-down to 2.5V to feed power to the Broadcom BCM5428 Switching chip.

Too much noise from those PSUs would cause the whole platform to fail, but if the platform works with 100% data integrity, then you know for a fact that the PSU is perfectly fine. PSU noise cannot somehow separately make its way to the output of the silicon switching chip then onto the Ethernet port magnetics and onto the Ethernet cable, without data integrity being affected. Just doesn’t happen.

Better/quieter PSUs are typically only driven by the need for ultra-low power (1.2V) sensitive silicon, usually for higher bit-rates and switching speeds, not for “cleaner” Ethernet streams.

[glevethan (Gregg)]

Thanks for the detailed explanation. Highly informative and shows the way these things work in conjunction with our streaming dacs.

Best
Gregg

[glevethan (Gregg)]

@TheFlash

We disagree but I’m ok with that. Manufacturers use SMPS for many reasons.

Linn have used SMPS for years. The highly acclaimed $40k NGKDS uses one. I do not think they would be using one in their flagship product if they felt its performance was not superior to other alternatives

[torbenrick (A Dane living in Hamburg)]

@Anupc - Does the same apply for an FMC?

Have a nice WE

Torben

[TheFlash (Nigel of Reiki Audio)]

@glevethan

Linn have used SMPS for years. The highly acclaimed $40k NGKDS uses one. I do not think they would be using one in their flagship product if they felt its performance was not superior to other alternatives

Linn get this right, as in the analogue world do Rega. The danger is when we extrapolate from this that any SMPS other than a cheap one is therefore as good.

[glevethan (Gregg)]

@TheFlash

The danger is when we extrapolate from this that any SMPS other than a cheap one is therefore as good.

I guess with that logic the same can be said about LPS’s as well

[TheFlash (Nigel of Reiki Audio)]

Absolutely.

Though of course we are all shaped by our experiences. Mine suggests that the performance spectrum of LPS’s I’ve heard overlaps with the performance spectrum of SMPS’s I’ve heard - and that experience informs my general (thought not universal) preference for LPS by default.

Your mileage may vary.

[Ermos (Erno)]

Also dCS are using switch-mode power supplies:

The amplifiers are powered by a combination of linear and switch-mode power supplies

Why does dcs prefer external clock and internal power supply

Mind you, dCS use both linear mode and switch-mode amplification. Anyway in the Bartók headphone DAC: Amplification for headphones In the past, it has been common for dCS owners to use the existing line out stage on their unit to drive headphones, by making up a special cable to run from the outputs to the headphones. It actually does this job reasonably well – even though not designed for the purpose – with its low output impedance and low harmonic content and distortion, and its ability to…

[James (James Cook)]

We are indeed. In fact, I believe all of our current devices are powered by hybrid power supplies - part linear, part switch-mode - not just the amplifiers.

Linear supplies are great at isolating from spurious mains activity, and switch-modes are great at providing stable DC, so it’s the best of both worlds. There’s also some further efforts with things like synchronising the switching elements to the unit’s clock circuitry to improve the ultimate audio performance of the system.

[Ermos (Erno)]

@James

There’s also some further efforts with things like synchronising the switching elements to the unit’s clock circuitry to improve the ultimate audio performance of the system.

Thanks James for clarifying. These further efforts: do you mean they are likely to appear in future dCS products, or already in existing ones?

[TheFlash (Nigel of Reiki Audio)]

@Anupc

if the platform works with 100% data integrity, then you know for a fact that the PSU is perfectly fine. PSU noise cannot somehow separately make its way to the output of the silicon switching chip then onto the Ethernet port magnetics and onto the Ethernet cable, without data integrity being affected. Just doesn’t happen.

Better/quieter PSUs are typically only driven by the need for ultra-low power (1.2V) sensitive silicon, usually for higher bit-rates and switching speeds, not for “cleaner” Ethernet streams.

I don’t think anyone who worries about/upgrades a switch PSU ever does so because they think their data integrity needs improving. There is more to the output of a switch than data integrity. Any switch, whether “audiophile” or not, which meets some pretty basic specs should provide data integrity, regardless of power supply.