@MarcelvdG
The Chord DAC implemented with FPGA-based DAC is better than the existing DAC chip.
XC6SLX9 FPGA may only be able to implement the most basic DA functions. It is better to buy an existing DAC chip.
What I want to express is that if the skill is not very strong, you still have to spend your own money to improve it. It is impossible to rely on the help of the community.
The Chord DAC implemented with FPGA-based DAC is better than the existing DAC chip.
XC6SLX9 FPGA may only be able to implement the most basic DA functions. It is better to buy an existing DAC chip.
What I want to express is that if the skill is not very strong, you still have to spend your own money to improve it. It is impossible to rely on the help of the community.
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I got your point.
Mine is different: if my purpose woluld be the final device itself, I will buy Ian's module, but my diy goal is to learn and design something from start to finish, even if I spend 20 times more money. Actually this is the funny part, that some people say "Ian's modules are the best, so let's try to do something even better".
Ian's modules may be the best so far, but the best that Ian or anyone else will ever do? Doubtful. If you can go for setting a new standard then by all means do it, but no reason other people have shouldn't fun with other goals.
The only thing I would say about FPGA programming is that most so-called hobbyists seem to keep their IP secret rather than sharing. In the past in diy forums there was a often a deeper level of sharing. What Marcel has done is exactly in line with that old spirit. OTOH, iancanada is in the business of supplying hobbyists with products.
The only thing I would say about FPGA programming is that most so-called hobbyists seem to keep their IP secret rather than sharing. In the past in diy forums there was a often a deeper level of sharing. What Marcel has done is exactly in line with that old spirit. OTOH, iancanada is in the business of supplying hobbyists with products.
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The statements about the Chord DAVE DACs seem to contradict each other. In post #7, yunyun claimed that a major difference between tigerente's DAC and the other DAC projects on this forum that use an FPGA is that tigerente implements the DAC function purely on an FPGA, like Chord. In post 22, tigerente wrote that tigerente's DAC indeed uses FPGA I/O cells as DAC, but that Chord uses NC7SZ175 flip-flops. In post 41, yunyun again refers to the Chord DAC as an FPGA-based DAC.
Which is correct? Are the Chord DACs using FPGA I/O cells or NC7SZ175 flip-flops for digital to analogue conversion? Looking at slide 6 of Chord's technology presentation, it sounds like they use separate flip-flops: "Ultra-low-noise sub-milli-ohm power planes for Pulse Array element flip-flops".
Whatever the correct answer may be, looking at the Chord website, I think their DAVE DACs are pretty much the opposite of tigerente's design:
Chord: absurdly long FIR filters for interpolation
tigerente: CIC filter with FIR equalization
Chord: multibit sigma-delta with second-order mismatch shaping (or at least that's my interpretation of slides 5 and 6 of https://chordelectronics.co.uk/wp-content/uploads/2016/09/DAVE-Technology-Presentation.pptx )
tigerente: basic single-bit sigma-delta
Chord: very expensive
tigerente: relatively cheap
So happy to be compared with Chord Dave, ~150$ and 10k$ha ha, I only take Chord Hugo I/II as a goal.
P/S I have never seen inside Chord Dave, only Hugo. But As per PCB design, I think Chord Hugo I/II is not multibit DAC
Your point is well taken, but its not exactly an apples to apples comparison. while you CAN just use the outputs of Ian's ES9028/38q2m directly, you should preferably add the IV stage. the DAC board doesn't have one, it relies on you to chose one and add it. it also doesn't have any kind of onboard regulators IIRC.. So Just dac hat and his IV, about $100. It doesn't have an onboard clock, or any kind of MCU either, because it is designed to be used with his fifo, so while it is a good value, it is not a functional equivalent and a price comparison not really valid IMO.
I think also, with FPGA intellectual property; its not always so easy to share everything, as development may come under the banner of a larger IP agreement between the developer and their FPGA supplier ie XILINX etc, which may be part of a larger corporate agreement, if an employer's high dollar DEV and simulation licenses are being used for audio on the side ... just food for thought, aside from the business of making money, which is of course, what it is ...
I'm sure the paid versions are even more powerful, but the free Xilinx tools are already remarkably powerful. Besides everything you need for logic synthesis, implementation and static timing analysis, you get free generators for various kinds of FIR filters (not the coefficients but the implementation in logic), CIC filters, FIFOs, many functions that you would need in typical receivers and a simulator (that's slower than the paid version when you simulate large designs, but otherwise it's the same).
I used free version of quartus. It limit the number of core of microprocessor to 1. So my computer will run very slowly.
About 3rd party IP (cic, fir,iir, ...) can not use in free version.
Design and Simulation by python to find coefficients .... And make all filters without CIC, FIR, IIR IP
Example
Implementing a CIC filter on FPGA – Electronic Design
Sorry, I've been mixing up your project with olo111's project Simple DSD modulator for dsc2 You use an Altera Cyclone IV FPGA, so no Xilinx at all.
i also use xilinx, so no problem. We can mix up. I'm very happy to discuss about theoryI hope to have the first prototype in a couple of months.
Since this is only a hobby and my hooby-time is very short, available means that I will share every part of this project (schematics, gerbers, code, measurements, knowledges...), so if you decide to build it, I will send you any information you need.
Since this is only a hobby and my hooby-time is very short, available means that I will share every part of this project (schematics, gerbers, code, measurements, knowledges...), so if you decide to build it, I will send you any information you need.