[okan]

My ru7 is not turning on. I've tried it with mac mini, iphone and android phone but no luck. I've also tried 3 different cables. Is there a way to reset it or is it dead?

 

[alexsh1]

Man that driver sucks. Many little pops, and dropouts @Andykong

I have the same issue and it is related to Cayin Windows drivers.

Cannot listen to any DSD in foobar2000 - other DACs are fine, but Cayin RU7 with latest Windows driver is not working. Many dropouts and shows 2.8MHz on the screen, but impossible to listen to DSD properly.

Any idea how to fix this @Andykong ?

 

[alexsh1]

Yes, you're right. The Cayin Driver is awful. I'm now using the Native windows generic driver after uninstalling cayin drivers. The clicking/pop sound is significantly reduced. It still happens from time to time. But it's not too frequent now. Btw with or without cayin drivers, i have not been able to use the master volume control on my PC when i connect RU7. I always have to adjust volume by clicking + and - on the RU7. Is there anyway i can use the volume control on my PC aswell when RU7 is connected ?

How did you make windows generic driver work?

The Master volume control on a PC won't work. You have to use RU7 volume control only.

 

[listen4joy]

Review

 

[alexsh1]

Review

That’s a very fresh one

 

[Yanec]

Review

Analog devices vary A LOT in their sound. It's meaningful to use more precise terms.

 

[oldkid]

Review

Very disappointing review. RU7 is not a R2R DAC !

 

[Yanec]

Very disappointing review. RU7 is not a R2R DAC !

The RU7 DAC does indeed use a resistor network, however, it isn't R2R.

1. Purpose and Design of a 1-Bit resistor DAC The RU7 network operates based on pulse-density modulation which involves very high-frequency switching of a single bit to represent audio waveforms. This single-bit approach is fundamentally different from the multi-bit, precise resistor matching found in traditional R2R ladders.
2. Architecture:
   • Resistor Network in 1-Bit DAC: This network technically forms a ladder, but its operation and design are optimized for DSD's 1-bit high-frequency data stream. This is less about the precise linear stepping through each binary level (as in R2R) and more about converting a very high-rate bitstream into an analog signal.
   • R2R DAC: Uses a multi-bit approach where each level of the digital code directly corresponds to a specific analog output through a resistor ladder. Each bit has a resistor that doubles in value as you move through the ladder, providing a direct and proportional analog representation of the digital input.
3. Conversion Method:
   • 1-Bit DAC for DSD: Uses high-speed switching and often relies on oversampling and noise shaping to achieve high fidelity, focusing on the purity of the DSD format which inherently uses 1-bit depth at a very high sampling rate.
   • R2R DAC: Converts digital signals into analog by summing currents through a network of precisely matched resistors, providing a direct analog equivalent of the digital input without the need for oversampling or complex filtering. R2R DACs are not inherently designed for 1-bit but rather for multi-bit PCM audio.

 

[alexsh1]

I'll paste my reply from another thread as it is useful to save people from being misled to believe that these 1-bit resistor DACs are R2R.

The RU7 DAC does indeed use a resistor network, which might initially seem similar to the R2R ladder approach. However, there are important distinctions in how these networks function and are implemented.

1. Purpose and Design of a 1-Bit resistor DAC The RU7 network operates based on pulse-density modulation which involves very high-frequency switching of a single bit to represent audio waveforms. This single-bit approach is fundamentally different from the multi-bit, precise resistor matching found in traditional R2R ladders.
2. Architecture:
   • Resistor Network in 1-Bit DAC: This network technically forms a ladder, but its operation and design are optimized for DSD's 1-bit high-frequency data stream. This is less about the precise linear stepping through each binary level (as in R2R) and more about converting a very high-rate bitstream into an analog signal.
   • R2R DAC: Uses a multi-bit approach where each level of the digital code directly corresponds to a specific analog output through a resistor ladder. Each bit has a resistor that doubles in value as you move through the ladder, providing a direct and proportional analog representation of the digital input.
3. Conversion Method:
   • 1-Bit DAC for DSD: Uses high-speed switching and often relies on oversampling and noise shaping to achieve high fidelity, focusing on the purity of the DSD format which inherently uses 1-bit depth at a very high sampling rate.
   • R2R DAC: Converts digital signals into analog by summing currents through a network of precisely matched resistors, providing a direct analog equivalent of the digital input without the need for oversampling or complex filtering. R2R DACs are not inherently designed for 1-bit but rather for multi-bit PCM audio.

There is an interview with Rob Watts (designer of Dave and Mojo 2 DACs) of Chord Electronics
about pros and cons of different DAC architectures.

 

[Yanec]

There is an interview with Rob Watts (designer of Dave and Mojo 2 DACs) of Chord Electronics
about pros and cons of different DAC architectures.

Off topic here.
Important part of this is the perspective.
The pro's and con's are different from the perspective of the producer and from the perspective of the consumer.

As a consumer, I personally use both delta-sigma and r2r and love both, just for different applications.

 

[alexsh1]

They are different from the perspective of the producer and from the perspective of the consumer.

This is a big topic, but in general I like the overview of deferent DAC based on architecture. Maybe one day, I’ll try to build mine ))

If you watch the video above, you would see that there has been disagreement about R2R and Delta-Sigma DACs between the presenter and the designer.

Come back to what you are saying they are different even from one consumer to the other consumer.

 

[Yanec]

This is a big topic, but in general I like the overview of deferent DAC based on architecture. Maybe one day, I’ll try to build mine ))

If you watch the video above, you would see that there has been disagreement about R2R and Delta-Sigma DACs between the presenter and the designer.

Come back to what you are saying they are different even from one consumer to the other consumer.

Always good to watch such things. I have seen that video personally and I do agree with one of them more...

Designing own stuff is amazingly engaging, but in the case of r2r one can only count on ready-made integral chips as matching resistors to at least 0.01% isn't possible at home.

 

[alexsh1]

Always good to watch such things. I have seen that video personally and I do agree with one of them more...

Designing own stuff is amazingly engaging, but in the case of r2r one can only count on ready-made chips as matching resistors to at least 0.01% isn't possible at home.

Not correct - 0.01% resistor are available. I ordered many times custom made resistors with a low tempco. Unfortunately, after Covid the lead time for such resistors could be like 50 weeks. Crazy

 

[Yanec]

Not correct - 0.01% resistor are available. I ordered many times custom made resistors with a low tempco. Unfortunately, after Covid the lead time for such resistors could be like 50 weeks. Crazy

Let me help you understand the difference between a resistor labelling and the actual measured tolerance of implemented r2r pair.

The labeling of resistors as "0.01%" (the methodology of labelling is another interesting story) refers to individual tolerance, meaning the resistor's resistance value will be within 0.01% of its stated nominal value.

Matching Resistor Pairs: In a R2R ladder DAC, the minimum 0.01% is per pair not just about individual resistors having a tight tolerance but actual operational performance measured per pair. Each pair.

Even if each resistor is within a 0.01% tolerance, if they're paired with others that are at the opposite ends of this tolerance, it will exponentially decrease the tolerance. Your network design and soldering could divide this by a multiple.

As Rob said, for a reason, in the video you shared, it's easy to make a R2R ladder it's extremely difficult, even for big experienced companies, to make it measure up to standard so that it can deliver transparent (16 bit), and impossible to achieve transparency for 24 bit material (0.001% pair tolerance)

Everyone buys resistors labelled 0.01% for home experiments but how do these measure at the end?

Let's refrain from further off-topic. Sorry if I was harsh but I have 0.001% tolerance for uninformed conclusions telling me "not correct".

 

[alexsh1]

I just love it when half-informed forum experts say "incorrect". I have spent decades in this and know Rob from the video very well, from actual work. I don't give free lessons but let me rub your nose a bit as you said incorrect in tepky to kind messages.

Show me a tolerance measurement and SINAD of an r2r dac ladder you made.

Do you believe you soldered on your knees or in your garage an overall 0.01% tolerance r2r ladder?

The labeling of resistors as "0.01%" (the methodology of labelling is another interesting story) refers to individual tolerance, meaning the resistor's resistance value will be within 0.01% of its stated nominal value.

Matching Resistor Pairs: In an R2R ladder DAC, the minimum 0.01% is per pair not just about individual resistors having a tight tolerance but actual operational performance measured per pair, each pair.

Even if each resistor is within a 0.01% tolerance, if they're paired with others that are at the opposite ends of this tolerance, it will exponentially decreas the tolerance and your network design and soldering would divide this by a multiple.

For ultra-high precision applications, some manufacturers or specialized vendors offer us expensive, certified matching service where resistors are not only produced to a high tolerance but also grouped into matched pairs or sets based on measured values.

Tell me with which of them did you work with? I know them all, by names. Oh, you don't you just know yours are matched...

Since we are talking about self made dacs, tell me how do you measure at home that the tolerance of a r2r pair is within 0.01%?

And since we don't use only 16 bit red book files but also a lot of 24 bit material, do you know what is the pair-level tolerance needed there? 0.001% , oh wait you bought that from AliExpress too?

Now let's refrain from further off-topic spam.

You have started your reply in extremely rude manner though I can see that your thread has been edited now.

The world of metrology my biggest hobby. I may not spend decades on this, but I know what I am talking about.
As you correctly pointed out 0.01% refers to an individual resistor tolerance, but this is not what we are discussing. We are discussing temperature coefficient, i.e. how resistance change with temperature.

Referring to matching pair, there are several manufacturers like Vishay, doing voltage dividers i.e. a matching pair of resistors with a very tight tempco. There is a guy called Edwin Pettis in the USA who manufactures precision resistors and others.
It is possible to test tempco of an individual resistor or a pair at home in a small self-built oven connected to a PC or a Raspberry Pi running a Python script.

Actually as we speak I have on my desk several matching pairs of resistors with 1ppm or 0.0001% (this is not individual tempco but a matching resistors ratio tempco). These were custom made for me at a lab.

I agree with you building at home anything 12 bit or even 16 bit is very hard. And anything with more than 20 bit is literally impossible.

The point of this discussion is that 0.01% or better tempco matching resistor pairs are available at home. Of course they are expensive and custom made and have to be ordered with a long lead time. I shall rest my case now as a half-informed forum expert lol )