Member PCB set Transformer FPGA
leadbelly 1 1 1
Bvtrinh 1 0 1
32y0 1 0 0
pluplog 1 0 1
randytsuch 1 0 0
Raj1 1 0 1
I'm assuming this is what I need for balanced output? Already have an output stage.
leadbelly 1 1 1
Bvtrinh 1 0 1
32y0 1 0 0
pluplog 1 0 1
randytsuch 1 0 0
Raj1 1 0 1
I'm assuming this is what I need for balanced output? Already have an output stage.
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That's correct. The transformer is only needed when you want to make a balanced version and drive an unbalanced input with it.
Looks like we are not getting enough interest for the group buy. Any chance we can go ahead with a low count?
Would it not make sense to pursue the non-valve version of this design which the designer views as comparable in performance at much lower cost?
Perhaps there will be more interest.
Marcel have you done a GB for your sand version?
You mentioned it was also published somewhere I believe? If I’m remembering correctly, where can I find it?
Perhaps there will be more interest.
Marcel have you done a GB for your sand version?
You mentioned it was also published somewhere I believe? If I’m remembering correctly, where can I find it?
PS I don’t wish to detract from or minimize what is obviously a very interesting, thoughtful and high performance design.
I simply think the cost is prohibitive to most.... and if performance isn’t compromised from a lower cost, more environmentally friendly option it should be considered as a viable alternative if this GB can’t get off the ground.
I simply think the cost is prohibitive to most.... and if performance isn’t compromised from a lower cost, more environmentally friendly option it should be considered as a viable alternative if this GB can’t get off the ground.
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I haven't started a group buy for either version, Leadbelly started this thread for the version with valves.
Anyway, you can find the technical details of the solid-state version on this forum, 74AHC02 and 74AHC08 DAC with 97 dB(A) dynamic range The solid-state version is less expensive than the valve version, but it still cost me around 500 euros. Almost half of that is due to the FPGA module. The four-layer board is also expensive when you order only one of them, like I did.
Anyway, you can find the technical details of the solid-state version on this forum, 74AHC02 and 74AHC08 DAC with 97 dB(A) dynamic range The solid-state version is less expensive than the valve version, but it still cost me around 500 euros. Almost half of that is due to the FPGA module. The four-layer board is also expensive when you order only one of them, like I did.
So, one could assume roughly 40% cost of the valve version in total?
I assume there will be price breaks on the module if enough GB members get in and it’s included in the GB?
Perhaps that could help realize both the valve and sand versions at reduced costs.
I assume there will be price breaks on the module if enough GB members get in and it’s included in the GB?
Perhaps that could help realize both the valve and sand versions at reduced costs.
A single ended valve version would be less expensive, no transformer required.
The FPGA board is always required, and it not cheap though.
Would the size reduction in the PWB for a single ended output make for significant savings?
Randy
The FPGA board is always required, and it not cheap though.
Would the size reduction in the PWB for a single ended output make for significant savings?
Randy
With the single-ended version you can half the size of the (single-layer) reconstruction filter board, half the number of potcores and almost half the number of polystyrene capacitors. The four-layer main board stays as is, though. Rough estimate: maybe 100 euros less than a balanced version without output transformers, 100 euros plus 274.92 dollars (plus taxes) less than a balanced version with output transformers.
See pages 4 to 8 of the attachment for the filter options.
See pages 4 to 8 of the attachment for the filter options.
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Other ideas to reduce costs, most of which require some serious redesigning:
A. Make a native DSD version with raw DSD interface; this eliminates all digital signal processing, so you don't need an FPGA module anymore. The obvious disadvantage is that the DAC can't play PCM anymore. (The disadvantages of DSD compared to PCM are ultrasonic noise, unsuitability for editing and the inability to dither it properly.)
B. Keep the digital signal processing, but port it to a cheaper FPGA module.
C. Use smaller potcores.
D. See how far you get with only two PCB layers. I have no idea what noise floor this would lead to, though.
A. Make a native DSD version with raw DSD interface; this eliminates all digital signal processing, so you don't need an FPGA module anymore. The obvious disadvantage is that the DAC can't play PCM anymore. (The disadvantages of DSD compared to PCM are ultrasonic noise, unsuitability for editing and the inability to dither it properly.)
B. Keep the digital signal processing, but port it to a cheaper FPGA module.
C. Use smaller potcores.
D. See how far you get with only two PCB layers. I have no idea what noise floor this would lead to, though.
If you read the whole thread, you'll see that the group buy had dwindled to only include the board set, as the numbers and logistics just didn't make sense for FPGA or transformers.
If one was so inclined as to redesign for lower cost, the only target worth attacking is a lower cost FPGA port. Is there a more radical option, such as something as commoditized as a Raspberry Pi? Is there some high horsepower development board out there, say with daughterboard FPU or whatever functions might be required?
If one was so inclined as to redesign for lower cost, the only target worth attacking is a lower cost FPGA port. Is there a more radical option, such as something as commoditized as a Raspberry Pi? Is there some high horsepower development board out there, say with daughterboard FPU or whatever functions might be required?
HenSch and myself have expressed interest in a group buy for the original Valve DAC PCB. Is anyone else interested?
Hi, are you sure you are in the right thread and not the more recent nautiboy GB for the DSD DAC?
Yes this is the correct one. I have already purchased the DSD only PCB. In the main thread, the original design came up and there was a little interest in getting the original PCB made again.
Well, I have no interest in stepping on anyone's toes. If there is sufficient interest and MarcelvdG is still on board, I can update and run a group buy.
I think he's on board? He was the one that pointed me to this thread. I figured it would be neat to have the version that's "normal" and doesn't need hqplayer or a similar solution along with the DSD one.
Valve DAC from Linear Audio volume 13
Valve DAC from Linear Audio volume 13
Thanks for pointing that out. I will go through my emails and get the PCB house to requote for lower quantity and current prices.
