Just a curiosity.
Why my DAC Gustard R26 if interfaced via USB by Mac makes available a max PCM frequency of 384 KhZ
while if interfaced in UPnP it has a 784 KhZ frequency ?
while if interfaced in UPnP it has a 784 KhZ frequency ?
hi @Mahatma63,
It’s probably related to DoP over USB.
macOS is not able to send raw DSD streams. That’s why the DSD over PCM standard has been developed: to send raw DSD in a fake PCM stream.
To identify it as such, there are 8 bit markers in it.
And the presence of these markers doubles the need of bandwidth, thus explaining why on a mac only half of the max DSD rate is available.
@Antoine , I am speaking of PCM frequency, not DSD.
If want to upsample PCM, with a USB connection I have a maximum 384 KhZ, via UPnP I can go further to 768 KhZ
From the R26 User Manual:
Specifications
Input
• COAX/AES/OPT :PCM 16-24bit/44.1-192kHz；DSD DOP64
• USB ：
PCM 16-32bit/44.1-768kHz；
DSD DOP64-DOP256；
NATIVE DSD：DSD64-DSD512
OS support: Windows 7~11 32/64bit；macOS；Linux
• IIS：PCM 16-32bit/44.1-768kHz；DSD DOP64-DOP256；
NATIVE DSD：DSD64-DSD1024
• LAN: ROON UPNP (more in the future)
• Bluetooth: LDAC、AAC、SBC、APTX、APTX LL、APTX HD
• 10M Clock in： 50 Ohm BNC，0dBm-20dBm，square wave 0.2V-3.3V，sinewave 0.5-3.3V。
*Make sure your Audio MIDI Setup settings for this DAC reflect the maximum sample-rate of the DAC… Also, check if you have the current firmware installed in your DAC…
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What is your setting for PCM ‘NOS’ ?
We are assuming the User Manual is correctly written and actually reflects sample-rate information in a way that we would interpret as being the way it is implemented… I believe the R26 internally interpolates PCM sample-rates and decimates 1-bit PDM (DSD) to PCM if not set to ‘DSD Direct’… So how the PCM interpolations are handled may be completely different for the different interface protocols (USB and Ethernet).
Also, please paste your debug information report here… It is found here: Settings → My Account → Help → Debug info
Hi @Agoldnear.
PCM NOS → Enable
Debug info:
Audirvana Studio 2.9.5 (20906)
macOS Version 15.2 (Build 24C101) ARM64 with 16GB physical RAM
Connected account of : Marco Brivio
NETWORK
Status: available
Local network access: allowed
SIGNAL PROCESSING:
Polarity Inversion:
Globally: OFF
Per track: ON
Effects plugins NOT ACTIVE
UPSAMPLING:
r8brain not in use
r8brain filter parameters
Bandwidth = 99.5%
Stop band attenuation 218dB
Phase linear
AUDIO VOLUME:
Max allowed volume: 100
Replay Gain: None
SW volume control: OFF
LIBRARY SETTINGS:
Sync list: 1 folders
AUTO: /Volumes/MUSIC ARCHIVE/
iTunes/Music library synchronization: not synchronized
Sort and display order: en
Library database path: /Users/marcobrivio/Music/Audirvana Database/AudirvanaDatabase.sqlite
Local audio files fingerprinting
Tracks with no MBID: 6888
Remote Control server:
Listening on on port 49619
ACTIVE STREAMING SERVICES
Qobuz: Connected as Qobuz Studio
HRA-Streaming: Connected as SUBSCRIPTION
APPEARANCE SETTINGS:
UI theme: dark
Font size: large
Language: English
Show album covers in tracks list: yes
Source list sorted:
My Music
Streaming
Local
Radios
Podcasts
Startup view: My Music: Albums
Show local extended in source list: yes
Use media keys: no
Use media keys for volume control: yes
Use Apple Remote: yes
Number of paired remotes: 0
Remote pairing code required: yes
Screen saver disabled: yes
=================== AUDIO DEVICE ========================
Active method: Local
Max. memory for audio buffers: 13312MB
Local Audio Engine: CoreAudio
Exclusive access: ON
Integer mode: ON
Use max I/O buffer size: ON
Actual I/O buffer frame size: 512
Preferred device:
Gustard Gustard USB Audio 2.0
Model UID:Gustard USB Audio 2.0:20B1:3033
UID:AppleUSBAudioEngine:Gustard:Gustard USB Audio 2.0:1100000:1
Active Sample Rate: 705.6kHz
Hog Mode is off
Bridge settings:
Sample rate limitation: 384kHz
Sample rate switching latency: none
Limit bitdepth to 24bit: OFF
Mute during sample rate change: OFF
Selected device:Gustard USB Audio 2.0
Manufacturer: Gustard
Model name: Gustard USB Audio 2.0
Model UID: Gustard USB Audio 2.0:20B1:3033
UID: AppleUSBAudioEngine:Gustard:Gustard USB Audio 2.0:1100000:1
USB Vendor ID: 0x20b1
USB Product ID: 0x3033
ID 0x3f
10 available sample rates up to 768000Hz
44100
48000
88200
96000
176400
192000
352800
384000
705600
768000
Audio buffer frame size : 212 to 4096 frames
Current I/O buffer frame size : 512
Volume Control
Physical: No
Virtual: No
Max volume alert: Enabled
MQA capability
Auto-detect MQA devices: Yes
MQA Decoder device
DSD capability
DSD via PCM 1.1
Device audio channels
Preferred stereo channels L:1 R:2
Channel bitmap: Ox3, layout:
Channel 0 mapped to 0
Channel 1 mapped to 1
Audio channels in use
Number of channels: 2
Use as stereo device only: No
Simple stereo device: Yes
1 output streams:
Number of active channels: 2, in 1 stream(s)
Channel #0 :Stream 0 channel 0
Channel #1 :Stream 0 channel 1
Stream ID 0x40 2 channels starting at 1
30 virtual formats:
2 ch Mixable linear PCM Interleaved 32 little endian Signed Float 768kHz
2 ch Mixable linear PCM Interleaved 32 little endian Signed Float 705.6kHz
2 ch Mixable linear PCM Interleaved 32 little endian Signed Float 384kHz
2 ch Mixable linear PCM Interleaved 32 little endian Signed Float 352.8kHz
2 ch Mixable linear PCM Interleaved 32 little endian Signed Float 192kHz
2 ch Mixable linear PCM Interleaved 32 little endian Signed Float 176.4kHz
2 ch Mixable linear PCM Interleaved 32 little endian Signed Float 96kHz
2 ch Mixable linear PCM Interleaved 32 little endian Signed Float 88.2kHz
2 ch Mixable linear PCM Interleaved 32 little endian Signed Float 48kHz
2 ch Mixable linear PCM Interleaved 32 little endian Signed Float 44.1kHz
2 ch Non-mixable linear PCM Interleaved 32 little endian Signed Integer 768kHz
2 ch Non-mixable linear PCM Interleaved 32 little endian Signed Integer 705.6kHz
2 ch Non-mixable linear PCM Interleaved 32 little endian Signed Integer 384kHz
2 ch Non-mixable linear PCM Interleaved 32 little endian Signed Integer 352.8kHz
2 ch Non-mixable linear PCM Interleaved 32 little endian Signed Integer 192kHz
2 ch Non-mixable linear PCM Interleaved 32 little endian Signed Integer 176.4kHz
2 ch Non-mixable linear PCM Interleaved 32 little endian Signed Integer 96kHz
2 ch Non-mixable linear PCM Interleaved 32 little endian Signed Integer 88.2kHz
2 ch Non-mixable linear PCM Interleaved 32 little endian Signed Integer 48kHz
2 ch Non-mixable linear PCM Interleaved 32 little endian Signed Integer 44.1kHz
2 ch Non-mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 768kHz
2 ch Non-mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 705.6kHz
2 ch Non-mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 384kHz
2 ch Non-mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 352.8kHz
2 ch Non-mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 192kHz
2 ch Non-mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 176.4kHz
2 ch Non-mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 96kHz
2 ch Non-mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 88.2kHz
2 ch Non-mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 48kHz
2 ch Non-mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 44.1kHz
40 physical formats
2 ch Mixable linear PCM Interleaved 32 little endian Signed Integer 768kHz
2 ch Mixable linear PCM Interleaved 32 little endian Signed Integer 705.6kHz
2 ch Mixable linear PCM Interleaved 32 little endian Signed Integer 384kHz
2 ch Mixable linear PCM Interleaved 32 little endian Signed Integer 352.8kHz
2 ch Mixable linear PCM Interleaved 32 little endian Signed Integer 192kHz
2 ch Mixable linear PCM Interleaved 32 little endian Signed Integer 176.4kHz
2 ch Mixable linear PCM Interleaved 32 little endian Signed Integer 96kHz
2 ch Mixable linear PCM Interleaved 32 little endian Signed Integer 88.2kHz
2 ch Mixable linear PCM Interleaved 32 little endian Signed Integer 48kHz
2 ch Mixable linear PCM Interleaved 32 little endian Signed Integer 44.1kHz
2 ch Mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 768kHz
2 ch Mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 705.6kHz
2 ch Mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 384kHz
2 ch Mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 352.8kHz
2 ch Mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 192kHz
2 ch Mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 176.4kHz
2 ch Mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 96kHz
2 ch Mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 88.2kHz
2 ch Mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 48kHz
2 ch Mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 44.1kHz
2 ch Non-mixable linear PCM Interleaved 32 little endian Signed Integer 768kHz
2 ch Non-mixable linear PCM Interleaved 32 little endian Signed Integer 705.6kHz
2 ch Non-mixable linear PCM Interleaved 32 little endian Signed Integer 384kHz
2 ch Non-mixable linear PCM Interleaved 32 little endian Signed Integer 352.8kHz
2 ch Non-mixable linear PCM Interleaved 32 little endian Signed Integer 192kHz
2 ch Non-mixable linear PCM Interleaved 32 little endian Signed Integer 176.4kHz
2 ch Non-mixable linear PCM Interleaved 32 little endian Signed Integer 96kHz
2 ch Non-mixable linear PCM Interleaved 32 little endian Signed Integer 88.2kHz
2 ch Non-mixable linear PCM Interleaved 32 little endian Signed Integer 48kHz
2 ch Non-mixable linear PCM Interleaved 32 little endian Signed Integer 44.1kHz
2 ch Non-mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 768kHz
2 ch Non-mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 705.6kHz
2 ch Non-mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 384kHz
2 ch Non-mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 352.8kHz
2 ch Non-mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 192kHz
2 ch Non-mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 176.4kHz
2 ch Non-mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 96kHz
2 ch Non-mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 88.2kHz
2 ch Non-mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 48kHz
2 ch Non-mixable linear PCM Interleaved 24 little endian Signed Integer aligned high in 32bit 44.1kHz
Local devices found : 7
Device #0: ID 0x3f Gustard USB Audio 2.0
Manufacturer: Gustard
Model UID: Gustard USB Audio 2.0:20B1:3033
UID: AppleUSBAudioEngine:Gustard:Gustard USB Audio 2.0:1100000:1
USB Vendor ID: 0x20b1
USB Product ID: 0x3033
Model name: Gustard USB Audio 2.0
Device #1: ID 0x35 LG UltraFine Display Audio
Manufacturer: LG Electronics Inc.
Model UID: LG UltraFine Display Audio:043E:9A4B
UID: AppleUSBAudioEngine:LG Electronics Inc.:USB Audio:4141000:2
USB Vendor ID: 0x043e
USB Product ID: 0x9a4b
Model name: LG Electronics Inc. LG UltraFine Display Audio
Device #2: ID 0x5a MacBook Pro Speakers
Manufacturer: Apple Inc.
Model UID: Speaker
UID: BuiltInSpeakerDevice
Model name: Apple Inc. MacBook Pro Speakers
Device #3: ID 0x66 MJAudioRecorder
Manufacturer: MJ Audio Inc.
Model UID: MJRecordDeviceModelUID
UID: MJRecordDevice
Model name: MJ Audio Inc. MJAudioRecorder
Device #4: ID 0x70 MMAudio Device
Manufacturer: MMAudio Device contributors
Model UID: MMAudioDeviceModelUID
UID: MMAudioDevice
Model name: MMAudio Device contributors MMAudio Device
Device #5: ID 0x76 MMAudio Device (UI Sounds)
Manufacturer: MMAudio Device contributors
Model UID: MMAudioDeviceModelUID_UISounds
UID: MMAudioDevice_UISounds
Model name: MMAudio Device contributors MMAudio Device (UI Sounds)
Device #6: ID 0x7a Microsoft Teams Audio
Manufacturer: Microsoft Corp.
Model UID: MSLoopbackDriverDevice_ModelUID
UID: MSLoopbackDriverDevice_UID
Model name: Microsoft Corp. Microsoft Teams Audio
UPnP
UPnP network interface
Selected Network interface: Thunderbolt Ethernet Slot 2
Available Network interfaces:
Thunderbolt Ethernet Slot 2
UPnP devices found : 1
Device #0: ID 0x0 : Bose Soundbar 700
UID: uuid:9f24e98d-3398-abc1-77c3-e1f0f53b78dc
Location: http://192.168.1.88:8091/9f24e98d-3398-abc1-77c3-e1f0f53b78dc.xml
Manufacturer: Bose
Model name: Bose Soundbar 700
Chromecast
Chromecast devices found : 0
Must be that 
Could you explain what “Bridge settings” means ?
I do not use any network bridge between my computer and the DAC, the connection is a direct USB. I cannot explain the reason.
just put it at no limit and see
Are you connecting your DAC(s) through a USB hub?
Note below the bold text from your debug report…
What you are seeing here is that the R26 is PCM-centric and does not support a pure 1-bit PDM (DSD) signal path to output… Otherwise you would see sample-rates to 44.8MHz (DSD1024)… So the ‘Bridge’ is the interpolator in the DAC architecture… 705.6kHz is the DoP 1.1 PCM carrier sample-rate for 1-bit 11.2MHz PDM (DSD256). … The R26 decimates 1-bit DSD signals to multi-bit PCM for output.
Follow the advice from @RunHomeSlow 
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@RunHomeSlow Thank so much, I set the sample rate to “no limit” and now 768 KhZ has appeared among the possible choices. I didn’t realize there was such a choice because the maximum (explicit) rate was 384.
Thanks also to @Agoldnear for his precious support
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Keep in mind that there are no native recordings done above 352.8kHz or DSD256… all files above these sample-rates are up-sampled iterations of the original encoded sample-rate.
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