No, it doesn't seem to matter, I couldn't hear a difference anyway.
Yes, just another ground potential connection point, can be isolated if need be.
I am experimenting with this IV https://www.diyaudio.com/community/...s-input-nos-r-2r.354078/page-450#post-7748184. I used Solen PB-MKP-FC paralleled with multicap from my past projects as output caps - they sound better than WIMA. I replaced them with ClarityCap CMR. I heard a significant difference right away. These caps are huge!
@Seavan.
Sorry didn't see your post.
I think I prefer the sound of a piece of wire. 🤣
Does the Mu follower have low enough output impedance for your setup?
For me I found it didn't when driving a Clone Note and F5. The bass just didn't sound the same to me. That's why I found it so beneficial to DC couple the anode directly to the grid of the cathode follower. Take out the capacitor entirely. No capacitor can match a piece of wire, I suppose some may come close. The ClarityCap CMR do look interesting though, especially the embedded copper lattice.
How many hours have you put on the D3 now? I usually found after 50hrs it loosened up nicely and 100hrs completely.
🙏
Sorry didn't see your post.
I think I prefer the sound of a piece of wire. 🤣
Does the Mu follower have low enough output impedance for your setup?
For me I found it didn't when driving a Clone Note and F5. The bass just didn't sound the same to me. That's why I found it so beneficial to DC couple the anode directly to the grid of the cathode follower. Take out the capacitor entirely. No capacitor can match a piece of wire, I suppose some may come close. The ClarityCap CMR do look interesting though, especially the embedded copper lattice.
How many hours have you put on the D3 now? I usually found after 50hrs it loosened up nicely and 100hrs completely.
🙏
I think I put close to 100 hours on it now. It's definitely getting better, or my brain is breaking in to it 🙂
I put together the simultaneous board today and it worked right away! I think DAC has more resolution, but most importantly is sounds more musical. I could not stop listening. Thank you very much again!
100% with you on the wire vs capacitor 🙂. I am experimenting with this IV right now https://www.diyaudio.com/community/...s-input-nos-r-2r.354078/page-450#post-7748184. It's a single stage and there is only one output cap - I think output transformer is the only alternative. Can't wait to try your IV 🙂 I am not sure, but I think output impedance should be around 10k - definitely need to calculate. My pre-amp has 50k input impedance.
I don't believe that good measurements translate to good sound, but I posted some measurements of the ClarityCap CMR here https://www.diyaudio.com/community/...st-tht-i2s-input-nos-r-2r.354078/post-7894702.
I put together the simultaneous board today and it worked right away! I think DAC has more resolution, but most importantly is sounds more musical. I could not stop listening. Thank you very much again!
100% with you on the wire vs capacitor 🙂. I am experimenting with this IV right now https://www.diyaudio.com/community/...s-input-nos-r-2r.354078/page-450#post-7748184. It's a single stage and there is only one output cap - I think output transformer is the only alternative. Can't wait to try your IV 🙂 I am not sure, but I think output impedance should be around 10k - definitely need to calculate. My pre-amp has 50k input impedance.
I don't believe that good measurements translate to good sound, but I posted some measurements of the ClarityCap CMR here https://www.diyaudio.com/community/...st-tht-i2s-input-nos-r-2r.354078/post-7894702.
😆
Good job.
Yes I would agree, it contributed to a lower jitter sound from my experience too.
Interesting, might have to give them a go on the cathode follower output.
You're right, they are a bit too big for the PCB.
I aloud 40mm long by 30mm wide. Need to allow at least 50mm long by 38mm wide.
I aloud 40mm long by 30mm wide. Need to allow at least 50mm long by 38mm wide.
I hope you will like the CMR caps. I got 8.2uF/400V, they are significantly larger. Just for a reference: https://partsconnexion.com/product_images/downloads/CLARITY-81536.pdf
I think simultaneous board is designed to allow for 4 DAC boards. Can I ask you, do 2 or 4 boards improve sound significantly?
What power supply do you use for the tube IV?
I think simultaneous board is designed to allow for 4 DAC boards. Can I ask you, do 2 or 4 boards improve sound significantly?
What power supply do you use for the tube IV?
Thanks for the link. They really are quite massive.
Also noticed slightly more pronounced dynamics.
Unfortunately, I couldn't get the shunt reg to sound as good as the capmx. The only way I could get it sounding similar to the capmx was to isolate with a resistor. The sound was similar to a circuit using global feedback. Im guessing the active components were influencing the sound.
Better signal to noise ratio when paralleling. When running balanced you also get common mode noise rejection and partial cancelation of 2nd harmonic.
Also noticed slightly more pronounced dynamics.
Right now im using SSHV2, before I was using a capacitance multiplier unregulated.
Unfortunately, I couldn't get the shunt reg to sound as good as the capmx. The only way I could get it sounding similar to the capmx was to isolate with a resistor. The sound was similar to a circuit using global feedback. Im guessing the active components were influencing the sound.
Very interesting, I compared D3 with a tube IV powered by SSHV2 and a simple CLC. CLC sounds to me better hands down - more natural, spacious, detailed, musical and involving. However, I also tried the same IV with Miro's DAC AD1862 and the result is completely opposite. I have to admit, its not a very clean experiment since B+ was around 20V less with SSHV2.
I am a bit confused on the D3 compensation circuit that brings Vout on Riv (and TDA1541A) to 0V at 2mA. I assume that even when the Vout goes below the chip analog ground (+-25mV) the DAC output current still only flows back to the analog ground of the chip - the DAC Iout and static compensation current stay independent. Is it correct?
I have not populated the compensation circuit on the D3 board under assumption that it's a more pure approach if I do not need the Vout to be 0V. However, I am now thinking that I was wrong and the compensation circuit also plays significant role in reducing distortions as it really allows to double the Riv and stay within compiance of +-25mV.
I am plannig to build a second D3 for differential architecture and looking for suggestions for the IV stage.
I have not populated the compensation circuit on the D3 board under assumption that it's a more pure approach if I do not need the Vout to be 0V. However, I am now thinking that I was wrong and the compensation circuit also plays significant role in reducing distortions as it really allows to double the Riv and stay within compiance of +-25mV.
I am plannig to build a second D3 for differential architecture and looking for suggestions for the IV stage.
Hi Seavan,
The main challenge will be getting a suitable transformer for a good price. Thorsten recommended a microphone transformer for this purpose.
The AC and DC component of the signal will take a different path, but from my understanding all bit currents will end up back at +5V. Ill attach a conceptual schematic of the 1541A to make sense of.
I prefer using the 2mA current comp because I prefer the lower harmonic distortion. However, it does sound and measure lower noise without the current injection. Try both and see what you prefer in your system.
I've been thinking about using 2 x D3 running differential into a 1:1 transformer, which then drives the grid of my tube stage.
The main challenge will be getting a suitable transformer for a good price. Thorsten recommended a microphone transformer for this purpose.
Thank you for sharing conceptual schematic! I am not sure if I am reading it right. The Riv is between analog output and analog ground. The analog output connects to the current divider through the the switching network. The current divider is fed by -15V source. I think the current loop ends with the -15V supply!?
This article suggests to return bit-currents to +5V power supply with connecting Riv to +5V instead of analog ground https://www.mvaudiolabs.com/digital/tda1541-iv-stage-options/. The -15V supply stays in the current loop.
I agree, the best way to listen and make a decision on what I like the best.
Here is a very detailed description of TDA1541A internal schematic: https://www.mvaudiolabs.com/wp-content/uploads/2022/10/A-Monolithic-Dual-16-Bit-DA-Converter.pdf
This article suggests to return bit-currents to +5V power supply with connecting Riv to +5V instead of analog ground https://www.mvaudiolabs.com/digital/tda1541-iv-stage-options/. The -15V supply stays in the current loop.
I agree, the best way to listen and make a decision on what I like the best.
Here is a very detailed description of TDA1541A internal schematic: https://www.mvaudiolabs.com/wp-content/uploads/2022/10/A-Monolithic-Dual-16-Bit-DA-Converter.pdf
If you have not seen this post https://www.diyaudio.com/community/...ate-nos-dac-using-tda1541a.79452/post-7923376 it has a very interesting attachment: https://www.firstwatt.com/wp-content/uploads/2023/12/art_h2.pdf
Hi Guys,
I did ordered 2x D3 PCBs, I2S2Sim v2 and CMx boards from Ryan. Can't wait to have fun with this project. I do really look forward to enjoy this great design. Thank you for all the work which makes this possible for DIYers.
I want to use those two TDA1541s in parallel mode. I'm going to start with SPDIF receiver based on WM8804 with TCXO, to utilize PCIE Interface I already have - Pink Faun HEPA Bridge SPDIF version. I do plan to replace it with I2S version in the future and use such link directly. I do plan to use I2S isolator too. I'm not decided regarding final approach to I/V conversion and output stage yet - I'm considering options. I know that especially after Pedja Rogic's / Audial success, there is famous approach nowadays to use OPA861 as "ideal transistor" for I/V conversion. I do actually have TDA1541 based DAC right now with such an I/V conversion, however I'm biasing towards more traditional conversion approach based on resistor, as I do tend to find it most acoustically pleasurable to me in majority of cases. If I do think correctly, by using two TDA1541s in parallel mode, I'm able to use resistor with lower impedance than when I'm using single TDA1541. I'd love to use no more than 40 Ohms as suggested here: https://www.mvaudiolabs.com/digital/tda1541-iv-resistor-selection/#TDA_output. If I'm calculating right, I should get around 0.226V RMS on the output with 2x TDA1541s in parallel and 40 Ohm I/V resistors. I do already have a tube line pre-amp based on WE420A and 12AU7 with 10x amplification. At the end I should get around 2V RMS then, which seems right.
Questions for now:
I'm sorry for the long intro, firstly I'd like to consult with you regarding power supply.
I know we need 5V, GND for digital circuit on D3 board and I2S2Sim board, and floating 26V(-,+) for analog section of D3. I'm considering using Sigma 11 for 5V,GND which I believe should do the job nicely. However there is another very interesting power supply from IanCanada - LinearPi. It can be configured to +5V, -5V. As there is no ground reference on it's output, I'm assuming I need to create it using from +5V and -5V on LinearPi board by resistors and optionally buffer this ground reference using op-amp, which is going to make virtual ground. However, on the other hand with Sigma 11 it's pretty straightforward and plug & play as I have +V, GND output from the board.
1) What do you think on usage of LinearPi with Distinction D3 project? Is is still good if there is a need to create virtual ground, either passive or active?
2) As for the floating 26V for D3 board. I see there is - and + inputs. Does it means it's better to use +13V and -13V, as the difference of potentials is then 26V and there is no ground reference than to feed it by +26V to + and GND to - ?
I do want to keep separated GND for digital and analog circuits.
Many thanks!
I did ordered 2x D3 PCBs, I2S2Sim v2 and CMx boards from Ryan. Can't wait to have fun with this project. I do really look forward to enjoy this great design. Thank you for all the work which makes this possible for DIYers.
I want to use those two TDA1541s in parallel mode. I'm going to start with SPDIF receiver based on WM8804 with TCXO, to utilize PCIE Interface I already have - Pink Faun HEPA Bridge SPDIF version. I do plan to replace it with I2S version in the future and use such link directly. I do plan to use I2S isolator too. I'm not decided regarding final approach to I/V conversion and output stage yet - I'm considering options. I know that especially after Pedja Rogic's / Audial success, there is famous approach nowadays to use OPA861 as "ideal transistor" for I/V conversion. I do actually have TDA1541 based DAC right now with such an I/V conversion, however I'm biasing towards more traditional conversion approach based on resistor, as I do tend to find it most acoustically pleasurable to me in majority of cases. If I do think correctly, by using two TDA1541s in parallel mode, I'm able to use resistor with lower impedance than when I'm using single TDA1541. I'd love to use no more than 40 Ohms as suggested here: https://www.mvaudiolabs.com/digital/tda1541-iv-resistor-selection/#TDA_output. If I'm calculating right, I should get around 0.226V RMS on the output with 2x TDA1541s in parallel and 40 Ohm I/V resistors. I do already have a tube line pre-amp based on WE420A and 12AU7 with 10x amplification. At the end I should get around 2V RMS then, which seems right.
Questions for now:
I'm sorry for the long intro, firstly I'd like to consult with you regarding power supply.
I know we need 5V, GND for digital circuit on D3 board and I2S2Sim board, and floating 26V(-,+) for analog section of D3. I'm considering using Sigma 11 for 5V,GND which I believe should do the job nicely. However there is another very interesting power supply from IanCanada - LinearPi. It can be configured to +5V, -5V. As there is no ground reference on it's output, I'm assuming I need to create it using from +5V and -5V on LinearPi board by resistors and optionally buffer this ground reference using op-amp, which is going to make virtual ground. However, on the other hand with Sigma 11 it's pretty straightforward and plug & play as I have +V, GND output from the board.
1) What do you think on usage of LinearPi with Distinction D3 project? Is is still good if there is a need to create virtual ground, either passive or active?
2) As for the floating 26V for D3 board. I see there is - and + inputs. Does it means it's better to use +13V and -13V, as the difference of potentials is then 26V and there is no ground reference than to feed it by +26V to + and GND to - ?
I do want to keep separated GND for digital and analog circuits.
Many thanks!
Hi xoresiesi,
Just a few remarks -
You're very welcome!
Just a few remarks -
When paralleling 2 DACs you will get a distortion profile equal to 80 Ohms when using one 40 Ohm RIV resistor. Personally I prefer 13RIV with 2mA current injection.
The 5V GND doesn't need to be isolated. I use the same 5V supply for both the I2S2SIM PCB and the digital attenuators.
Usually split rails are referenced to GND in the middle which will not work with the Floating 26V supply. Just use the CMX PCB with a transformer (center tapped or dual secondaries) with no reference to GND. Some others have used shunt regs for the 26V supply with success. Personally I didn't noticed much of a difference here, the on board shunts do a great job at lowering noise. Do not reference minus of 26V supply to GND.