[Presence]

isn't Audio-gd's BNC 75ohm? not sure if I misunderstood. I haven't use external clock before.

For the R8[HE], because the 75ohm coax is converted to [75 ohm] BNC, you are correct - the clock input is 75ohm.
If you go to the Custom Option tab of the R-7HE Mk2 the clock input comes as 50 ohm but you can order it as 75 ohm.

You can put an ohm meter across the terminals to verify. If you are very good with a soldering iron, I believe one can replace the terminating SMT resistor on the digital board if you needed 50 ohm for the R8[HE] 10M clock retrofit.

 

[DACLadder]

The R8’s ext. 10M input impedance is 75 ohm. Design decision to keep costs low. No mods.

From R8 mk2 summary page…
If user want the R8 MK2 work with the external clock input , can update the firmware , the IN2 BNC input become the external 10MHz input. Download the R-8 EC firmware in the below link.The Extermal clock must be 10MHz, 75 ohm, 1-3Vp-p level, recommend the square wave output ,though sine wave also can work.

 

[Currawong]

I've only tried the Kitsune SU-1 and Soundaware D300REF as external clocks, with no audible difference switching while playing music to the R27HE. What has made the most difference has been: iFi Stream > SU-1 > R27HE (I2S, NOS mode) and using HQPlayer set to Closed Form M, LNS15, 20-bit. Then I feel the music inside me. It's fantastic.

To add to my post, rather than make another, I tried DSD as well. One of the things that has always struck me as remarkable about Kingwa's DSD ladder is that it doesn't result in that over-softened, vague sound that I've had from other ladder DACs that can process DSD. I'm sure I've posted this before. I tried both SACD rips and HQPlayer DSD up-sampling, and both are great.

 

[milkdudd]

with my humble experience with my friend’s C18 clock, i could have a good result with a long cable (3m) using a higher spec. LMR400 cable vs previously a simple RG400 cable which had some dropouts from time to time….hopefully this will help

Correct or not, I have come to accept the fact that a USB cable should be at least 1.5 m long to avoid "reflections" as they are described by people who know a lot more about this stuff than I do. Anyone ever heard if the 1.5 m rule applies to the BNC cable between clock and DDC, or the i2s cable between DDC and DAC?

 

[audiobill]

Correct or not, I have come to accept the fact that a USB cable should be at least 1.5 m long to avoid "reflections" as they are described by people who know a lot more about this stuff than I do. Anyone ever heard if the 1.5 m rule applies to the BNC cable between clock and DDC, or the i2s cable between DDC and DAC?

Yes for a BNC cable either clock or SPDIF, not sure about i2s cables.

 

[milkdudd]

Yes for a BNC cable either clock or SPDIF, not sure about i2s cables.

Okay thanks. It's surprising to me how many people buy exotic digital cables that are shorter then the 1.5 m minimum. There's no shortage of 1 m long (and shorter) USB and coax digital cables costing $500 and up. Sometimes way up. I know with i2s almost nobody uses longer than the minimum required to make the connection. I'll have to do some more research on that

 

[audiobill]

Okay thanks. It's surprising to me how many people buy exotic digital cables that are shorter then the 1.5 m minimum. There's no shortage of 1 m long (and shorter) USB and coax digital cables costing $500 and up. Sometimes way up. I know with i2s almost nobody uses longer than the minimum required to make the connection. I'll have to do some more research on that

Shorter lengths will still work, but 1.5m has been tested and shown to minimize reflections when transmitting the "digital" signal. I put digital in quotes since it's actually an analog signal in the form of a square wave, which is the sum of all odd order harmonic sinewaves of the desired frequency. Signal reflections in such a waveform can cause distortion commonly referred to as jitter, which negatively impacts the recovered and subsequently converted analog signal.

 

[FredA]

I've only tried the Kitsune SU-1 and Soundaware D300REF as external clocks, with no audible difference switching while playing music to the R27HE. What has made the most difference has been: iFi Stream > SU-1 > R27HE (I2S, NOS mode) and using HQPlayer set to Closed Form M, LNS15, 20-bit. Then I feel the music inside me. It's fantastic.

To add to my post, rather than make another, I tried DSD as well. One of the things that has always struck me as remarkable about Kingwa's DSD ladder is that it doesn't result in that over-softened, vague sound that I've had from other ladder DACs that can process DSD. I'm sure I've posted this before. I tried both SACD rips and HQPlayer DSD up-sampling, and both are great.

A good streamer indeed makes a difference. And the psu you use. Kingwa uses a regenerative power supply together with a rpi4 and said it brought a tangible improvement. Same for me using the usbridge sig with a nice Zerozone psu good for 5V/4a featuring an o-core transformer. My usbridge sig is modded to accept a 5.5/2.1 connector and i use a stiff, shielded and heavy (12awg) Audiolund dc cable. Real nice upgrade all combined.

 

[Currawong]

I tried the same input to the new R2R-11 with excellent results as well. It has more of that "bloom" that you get from lower-end R2R gear, but the up-sampling helped it hit a kind of mid-point where it sounded lovely.

 

[Presence]

John Swensen's tutorial on Clocking explores transmission of Sinewave (no harmonics) vs. Squarewave (infinite? harmonics) and the cable's ability to accurately/flatly transmit its harmonics so the squarewave still looks like a squarewave at the receiving end...

For anyone interested -

https://audiophilestyle.com/forums/topic/62477-john-swenson-tutoring-paper-considerations-regarding-usage-of-external-reference-clocks-etherregen-and-other-sine-vs-square-impedance-cables—and-a-money-saving-surprise-at-the-end/


From the same thread -

 

[Articnoise]

Correct or not, I have come to accept the fact that a USB cable should be at least 1.5 m long to avoid "reflections" as they are described by people who know a lot more about this stuff than I do. Anyone ever heard if the 1.5 m rule applies to the BNC cable between clock and DDC, or the i2s cable between DDC and DAC?

It was Steve Nugent of Empirical Audio that made the 1.5 meter rule of SPDIF cables. It was not quite right then and is certainly not today. It all depends on how fast the transceiver is However, it is true that an excessively short SPDIF cable can lead to reflections. For clock cables, it's true and should be as short as possible without folding. USB cables can also be short without any problems. Power cables, on the other hand, should be long to filter the mains from noise.

 

[PLGA]

Hi guys
My HE-1 Mkii preamp just arrived today!

Can't wait to see what it will bring to the table vs my beloved 2017 Master 1!

 

[JaMo]

@PLGA
Congrats! It sure looks good.
-Why not start a new thread about Your findings for the Audio-gd HE-1 Mk2?
/Jan

 

[FredA]

The HE-1 MKII is intriguing. It has an all new layout. The two pre boards are no more in mirror. Not that it had to, considering the shielding plates. This makes manufacturing simpler. The boards now have a front to back layout, like a car engine mounted longitudinally.

If i had shelf room to spare, i would probably already have the original model. I will stick with the he-9 for a while. . But i am tempted. Nice unit. Congrats, Pedro ! You'll taste the silky smooth treble and the blacker background.

 

[PLGA]

By the way, has anyone tried AGD ACSS master cables? Has anyone compared them to other ACSS cables?

The HE-1 is longer than the Master 1 and I think I will need to buy a pair of 2m long ACSS cables to place it.