Why does SPDIF basically suck?

[Superdad]

14 hours ago, Fitzcaraldo215 said:

What's better than asynch USB straight to the galvanically isolated DAC without any extra do dads or gizmos involved?

 

Remember, DACs which have digital isolators (what you refer to as galvanic isolation) ALWAYS have them on the I2S lines AFTER the USB input PHY/processor. (So far the ONLY exception to that is the new Auralic Vega G2, which uses the same Silanna isolator chip as our ISO REGEN, right at the input.)

 

Quote

Anticipating your likely answer, my Regen is out of the signal path gathering dust.  Do you want to buy it back?

 

No but I’ll sell you the much more advanced ISO REGEN.   Same 30-day money-back guarantee as you had with the original when you got it three years ago.

[Fitzcaraldo215]

15 hours ago, sandyk said:

 

Try using the Amber Regen with downloaded .flac files when converted to .wav/aiff  and saved to USB memory, and compare the SQ results with a direct conversion to .wav without the USB Regen.

The results will of course depend on just how good the rest of your system is.

 

That's best done using a USB memory stick, with the Regen powered via a12V Li Ion battery, and plugged into a USB2.0 port using an adaptor with both +5V and shield not connected through. (Use of +12V won't hurt the Regen with a light load like a USB memory stick.)

Sorry, not interested in your test, whatever you think it means.  I do not play stuff that way, and I do not intend to.  I have tested the Amber Regen in my system as I actually use it.  I think it slightly changes the sound.  However, I do think it improves it.

[jabbr]

2 hours ago, Superdad said:

 

Remember, DACs which have digital isolators (what you refer to as galvanic isolation) ALWAYS have them on the I2S lines AFTER the USB input PHY/processor. (So far the ONLY exception to that is the new Auralic Vega G2, which uses the same Silanna isolator chip as our ISO REGEN, right at the input.)

 

 

 

Please, @PeterSt isolates the Phasure NOS1a/G3 at the USB input 

 

[jabbr]

21 hours ago, Ralf11 said:

how does that noise get transmitted?  are you claiming it goes thru the optical cable?

It does! Toslink uses very cheap transceivers GIGO — not the photon’s fault

[Ralf11]

that might cause new noise, tho - not the same noise as the original?

 

 

but, either way, one should be able to see it pretty easily with the right instrumentation, no?

[Superdad]

3 hours ago, jabbr said:

Please, @PeterSt isolates the Phasure NOS1a/G3 at the USB input 

 

Ah, forgetful me. Indeed the current Phasure includes a board (again with the Silanna chip) to pass USB through input isolation.  Does it go directly USB>I2S, or does the galvanicly isolated signal come back out to then get fed into the main USB input of the DAC?  I don’t recall. 

[Panelhead]

   Many like the USB to Coax converters. They prefer to straight USB. Never personally tried the USB cleanup devises or a DDC. Happy with Thunderbolt or FW and a  FW to TB converter.

  Did make a better coax SPDIF cable recently. Used a 20” section of Belden 4505R 4K, UHD cable and crimp on Amphenol connectors that are listed as being 4K, UHD, 12 GHZ. Sounds the same as the Canare L-5CFB cable and Canare crimp on connectors it replaced. 

  The cable may be the strength of SPDIF transmission. The input receiver and output transmitter are not 4K compatible. If they were 768k/32 or DSD512 would be possible. 12 GB/sec is plenty of BW.

[esldude]

Only used Firewire on Windows machines, but I've found it has various low level noise issues many complain about with USB while asynch USB mostly avoids those.  If you've got older good DACs a good USB to SPDIF converter seems pretty good.  Apparently too many cheap DACs skimp on the USB connection. 

 

Of course using reasonably priced Prosumer recording devices with ASIO connected USB  is generally a really safe way to go for great price/performance ratio.  Main drawback is no remotes.  But an increasing number of such devices have remote control apps you can use via a phone to control playback. 

[sandyk]

3 hours ago, Panelhead said:

Did make a better coax SPDIF cable recently. Used a 20” section of Belden 4505R 4K, UHD cable and crimp on Amphenol connectors that are listed as being 4K, UHD, 12 GHZ. Sounds the same as the Canare L-5CFB cable and Canare crimp on connectors it replaced. 

 

 How much difference did it make compared with something like a Belden RG59U cable with decent 75 ohm BNC connectors on both ends ? (Belden RG 59U appears to have an attenuation of < 0.5dB at 1GHz and 3 feet length.)

[semente]

2 hours ago, esldude said:

Only used Firewire on Windows machines, but I've found it has various low level noise issues many complain about with USB while asynch USB mostly avoids those.  If you've got older good DACs a good USB to SPDIF converter seems pretty good.  Apparently too many cheap DACs skimp on the USB connection. 

 

Of course using reasonably priced Prosumer recording devices with ASIO connected USB  is generally a really safe way to go for great price/performance ratio.  Main drawback is no remotes.  But an increasing number of such devices have remote control apps you can use via a phone to control playback. 

 

I experimented with M-Audio and KRK Firewire DACs on MacOS in the past and had no issues with noise. Performance was far from what I was getting with my CD player, though.

[Whitigir]

SPDIF do not suck.  I have LKS004 that allows DPLL adjustments, even Coax out of a small player DX200 can lock into the highest DPLL, and USB can not, regardless of coming from laptop or expensive USB.  That is what physical evidence can show...

 

Coax also sounds better than USB input in my own experiences 

[PeterSt]

16 hours ago, Superdad said:

Ah, forgetful me. Indeed the current Phasure includes a board (again with the Silanna chip) to pass USB through input isolation.  Does it go directly USB>I2S, or does the galvanicly isolated signal come back out to then get fed into the main USB input of the DAC?

 

Alex, FWIW, virtually the latter because there's galvanic isolation a second time between USB and I2S.

The real reason could be that now the isolation means of the USB interface is

- updateable;

- exchangeable;

- adaptive to extra isolation means behind the first

- and it can be eliminated all together. 

 

Peter

[Panelhead]

8 hours ago, esldude said:

Only used Firewire on Windows machines, but I've found it has various low level noise issues many complain about with USB while asynch USB mostly avoids those.  If you've got older good DACs a good USB to SPDIF converter seems pretty good.  Apparently too many cheap DACs skimp on the USB connection. 

 

  I have only used Mac for audio. No low level noise here, FW drivers are always suspect on Windows platform. The same with TB today.

 Focusrite released a complete line of Clarett interfaces recently just for Windows. USB instead of Thunderbolt. Gave up on providing usable TB drivers for the Windows platform. Progress?

  Have found FW dac is better sounding on a TB buss with an Apple FW/TB adapter. Most the Mini’s at home have USB, FW, and TB buss.

 Have tried I2S and a USB 3.0/I2S converter. Jury is out on this. No USB 3.0 dacs or I2S output on Mini.

  That is like my comparison of AES to Coax. Sample size of one. 

[Panelhead]

7 hours ago, sandyk said:

 

 How much difference did it make compared with something like a Belden RG59U cable with decent 75 ohm BNC connectors on both ends ? (Belden RG 59U appears to have an attenuation of < 0.5dB at 1GHz and 3 feet length.)

  I have not tried the RG-59 bulk cable from Belden. Usually use RG-6. Did make few RG-59 cables with a more expensive Gotham bulk cable. Silver plated conductor and braid. Did sound different than Canare L-5CFB. Like the Canare better. Better balance. The silver plated seemed to emphasize highs. But Gotham silver plating may be primarily nickel, like the silver plating on Neutrik connectors.

[Panelhead]

6 hours ago, semente said:

 

I experimented with M-Audio and KRK Firewire DACs on MacOS in the past and had no issues with noise. Performance was far from what I was getting with my CD player, though.

  I have used the KRK dac for many years. Unique feature set. Did extensive board work on several. 

  They were slamming them out of the backdoor in Florida for less than 300.00 delivered. Purchased several.

  Decoupling and working on the PGA4311 circuit really added resolution. But feeding it 96/24 to get around the hardware upsampler and using playback software instead of iTunes pushed it past any disc spinner I have owned. Owned a few good ones too.

[semente]

5 hours ago, Panelhead said:

  I have used the KRK dac for many years. Unique feature set. Did extensive board work on several. 

  They were slamming them out of the backdoor in Florida for less than 300.00 delivered. Purchased several.

  Decoupling and working on the PGA4311 circuit really added resolution. But feeding it 96/24 to get around the hardware upsampler and using playback software instead of iTunes pushed it past any disc spinner I have owned. Owned a few good ones too.

 

I only used mine with iTunes and Redbook material. But my CD player is very good. The difference was so significant that I was unable to evaluate the effectiveness of RoomPerfect...