Return-to-zero shift register FIRDAC

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#262
MarcelvdG said:
So if I understand it correctly, Nick's USB-to-I2S bridge does the DoP-to-raw-DSD translation.
Click to expand...

Short answer yes - but my ADC is my first focus. Then I'll look at adding a DAC option. I think in the interim it will be faster using the JLSounds as an option for the RTZ. (it doesn't help that STM32 variants able to keep up with DSD are sold out in most places with a year backorder!)
 
#263
randytsuch said:
I saw nautibuoy used a JLSounds i2soverUSB board to generate DSD.
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Not quite Randy, I generally generate DSD from PCM using HQPlayer on a high power compute like yourself. The JLSounds is just a USB receiver to interface to the DAC, like Amanero but, IMO, superior with its isolation and reclocking.

I also have a Valve DAC an a DSC2, both of which use a Beaglebone Black running Botic as HQP NAA. One BBB interfaces to Hermes/Chronus and the other to ppy's isolator/reclocker.

I used the JLSounds with Marcel's prototype RTZ DAC simply because I had one spare and it's very easy to implement.

I'm not sure whether I'll use BBB or JLSounds for this project, or maybe I'll do both, but then I also have the possibility of this https://www.diyaudio.com/community/threads/simple-dsd-modulator-for-dsc2.370177/

I'm also going to load Daphile onto an Intel NUC I have available to see if that provides an alternative to HQP, perhaps for less critical listening.

Decisions, decisions!
 
#264
This thread is certainly getting pretty active. It'll be great if the result is a good number of implementations of Marcel's design. I'm hoping people will be more forthcoming about their builds and feedback on the results, when we did the Valve DAC GB a ot of people who participated didn't comment further.
 
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#266
I had a disappointing result with the 3A5 tube output stage this afternoon. No music, just a hum and identical in both channels. I've checked several times and I've definitely built it as per the schematic.

http://itsonlyaudio.com/ultranalog/cdenhancer/cdenhancer2_3a5.pdf

When I get time I'll hook-up one channel and see if I can work out what is happening but for now I've reinstalled the op-amp filter board and listened to some music - it still sounds excellent!
 
#269
nautibuoy said:
It's a transformer output so there shouldn't be any DC? My suspicions are based on the 3A5 being a DHT.

I didn't have time to investigate yesterday and today my spare time will go into working on my SLOB speaker project so this'll have to wait for a 'rainy day' when I can settle down with my 'scope and concentrate.
Click to expand...
I mean at the input side of the stage from the output of the dsd dac. Could also be a ground issue.
 
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#276
I'm starting to get the Group Buy organised so I've put together a spreadsheet with Google Sheets, link below.

I've copied in the list from #253. Please check that I've copied across your requirements correctly, amending as required, and populate your home country (which I'll use to calculate the onward shipping of PCBs).

Any additional members who wish to join the GB can add their name and requirements into a blank row - as said earlier, I'll keep this open until Sunday. After that I'll get a quote for the boards and populate the costs and, once that's done, I'll allow 5 days for people to pay and then order the boards based on those who've financially committed. Any changes to quantities/costs will get ironed out when I get the boards and start distributing them by adjusting the payments for onward shipping.

https://docs.google.com/spreadsheets/d/1uKnO0GdXeRVG1_gdMzKvs1F0184cyWlzM4Ul6nbt7Io/edit?usp=sharing
 
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#277
I've obtained a provisional quote for the PCBs and have populated the spreadsheet with indicative costs. The costs might still vary depending on the final quantities and how many GB subscribers actually follow-up on their interest with funds. The indicative costs don't yet include onward shipping from me to you.

Now will be a good time to make any adjustments to your requirements.

Please note that the costs assume that the group will fund two sets of the final PCBs for Marcel's use.

https://docs.google.com/spreadsheets/d/1uKnO0GdXeRVG1_gdMzKvs1F0184cyWlzM4Ul6nbt7Io/edit?usp=sharing

Incidentally, to illustrate the value of the GB, I obtained a quote for a set of 5 DAC and Filter PCBs (minimum order quantity) as if I were ordering just for myself, the cost with delivery would be in the region of £75.
 
#278
marcel,
found this HF dual from infineon BFS481. the RB is listed as 9.9 ohms. could be useful as low noise transistor..

.MODEL T349 NPN(
  • IS = 1.0519e-18 BF = 96.461 NF = 0.90617
  • VAF = 22.403 IKF = 0.12146 ISE = 1.2603e-14
  • NE = 1.7631 BR = 16.504 NR = 0.87757
  • VAR = 5.1127 IKR = 0.24951 ISC = 1.1195e-17
  • NC = 1.6528 RB = 9.9037 IRB = 0.00069278
  • RBM = 6.6315 RE = 2.1372 RC = 2.2171
  • CJE = 1.8168e-15 VJE = 0.73155 MJE = 0.43619
  • TF = 1.7028e-11 XTF = 0.33814 VTF = 0.12571
  • ITF = 0.0010549 PTF = 0 CJC = 3.1969e-13
  • VJC = 1.1633 MJC = 0.30013 XCJC = 0.082903
  • TR = 2.7449e-09 CJS= 0 VJS = 0.75
  • MJS = 0 XTB = 0 EG = 1.11
  • XTI = 3 FC = 0.99768)
 
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