Yes, although it may sound better if you load the LT3045 with a resistor to ground in order to run a little more current through the regulator than is really needed by the DAC. Its sort of an experimental thing, just have to try it to see if it helps. Maybe try something like 47R up to maybe something like 100R. Lower resistance is usually better so long as the regulator doesn't go into overtemp protection. Also, the resistor needs to be of sufficient wattage rating for whatever it will need to dissipate. The way this trick probably works is by increasing the loop gain of the regulator, since the regulator pass transistor gain will be somewhat current dependent.
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I will also change parts between both dacs to compare but it will make an A-B comparison difficult. And trying Andreas fifo on the D3 will also be an interesting experiment.
I think that I will try the Salas reflector D shunts on the vref first. I also have an ultrabib in tock but I’m missing some parts So this will have to wait.
the Rpi is powered by an Allo Shanti for the moment.
Is it also interesting to try in a constant current draw load (clocks)? Which type of resistor? wirewound (mills type)?
For 3.3v rails, I might use a (1/2-Watt or higher) Dale RN6, or similar. Any good quality metal film of sufficient power rating should work, especially for testing and to find the best resistance value. Could be different models of metal film resistors may vary in excess noise to some degree depending on particular construction details, such as, for example, how the endcaps are attached to the resistance element.
Not sure though exactly what you mean by, "constant current draw (clocks)." Clock oscillators tend to draw constant current although it may be modulated some at the oscillator frequency. Clock squaring circuits OTOH tend to draw current in pulses which are related to the clock square wave edges.
Not sure though exactly what you mean by, "constant current draw (clocks)." Clock oscillators tend to draw constant current although it may be modulated some at the oscillator frequency. Clock squaring circuits OTOH tend to draw current in pulses which are related to the clock square wave edges.
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I wrongly supposed that DRIXO would drew constant current so the effect of this shunt regulator would be less as the regulator doesn't need to adapt to any change in load.....
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Some interesting points Mallinson made in his patent include shunt regulator output impedance dropping as frequency goes up, and that the effect may be to help reduce jitter. In other words, he's saying the clock oscillator might be more stable and less jittery if the output impedance of its power supply is low at the clock frequency and perhaps higher. Series regulators OTOH have an output impedance, that at some frequency and above, starts to look more inductive to the load. We usually try to work around that by keeping impedance low at HF using bypass caps, and by using ground and power planes. What will work best in the end for some particular circuitry may not be known without some experimentation. There are of course some guidelines in textbooks and application notes for high-speed digital in particular, but a dac running with 5/6MHz clocks or maybe 11/12MHz is not the same as a dac clocked at 100MHz. What works best in terms of various design approaches may accordingly be different.
The group buy thread and ultrabib manual has details. (https://www.diyaudio.com/community/threads/gb-for-salas-sslv1-3-ultra-bib.322596/#post-5432184)
Please note if needed 5V operation, J3 must be <7.5ma. You must also use RED leds here the 1.85 vF type
Even if very happy with my latest PCM1794 DAC with SEN I/V from Patrick I was intrigued by the design of Andrea Clocks, FIFO and LT DAC.
Was a long journey with many logistic problem (I live in Vietnam and it's very hard to import anything) plus some technical issue that Andrea kindly help my to solve.
I attached few pictures, practically the whole DAC is based on the Andrea boards including the PSU with the exception of the 4V for the LT analog side that are the Salas Reflektor that I was obliged to redesign to fit in the chassis.
The clocks are the Driscoll 5,6 and 6.2Khz
I added a small board with 2 relays, moved by the 5V available in the battery board. One relay switch the 220V for the Reflector, the other one switch the FIFO supply from the PSU.
Regarding the sound... at the first listening I was impressed by the 3D presentation and the quality of the mid-high section but I also noticed the lack of low "punch" compared with the other PCM1794 DAC. I discussed this with Andrea and he suggest to give some time of burn-in. I have to say that he was right, just after few days the low level show up. Today, after almost one month that I play the DAC almost 3/4 hours every night the DAC is playing really well, the mid-high are impressive, the low are all there without being invasive, not to mention the 3D and the definition in the space of all the instruments.
Almost forgot to mention, the input is from the RPI that was laying around from some experiment that I did some years ago and abandoned. I give a try to the Andrea RPI interface with the TX-RX modules to connect the RPI through HDMI cable. I am surprised how well is playing, also thinking all the trouble that I get years ago with the RPI and Volumio.
Thanks Andrea for the incredible design you did!
Cheers,
Enrico
Was a long journey with many logistic problem (I live in Vietnam and it's very hard to import anything) plus some technical issue that Andrea kindly help my to solve.
I attached few pictures, practically the whole DAC is based on the Andrea boards including the PSU with the exception of the 4V for the LT analog side that are the Salas Reflektor that I was obliged to redesign to fit in the chassis.
The clocks are the Driscoll 5,6 and 6.2Khz
I added a small board with 2 relays, moved by the 5V available in the battery board. One relay switch the 220V for the Reflector, the other one switch the FIFO supply from the PSU.
Regarding the sound... at the first listening I was impressed by the 3D presentation and the quality of the mid-high section but I also noticed the lack of low "punch" compared with the other PCM1794 DAC. I discussed this with Andrea and he suggest to give some time of burn-in. I have to say that he was right, just after few days the low level show up. Today, after almost one month that I play the DAC almost 3/4 hours every night the DAC is playing really well, the mid-high are impressive, the low are all there without being invasive, not to mention the 3D and the definition in the space of all the instruments.
Almost forgot to mention, the input is from the RPI that was laying around from some experiment that I did some years ago and abandoned. I give a try to the Andrea RPI interface with the TX-RX modules to connect the RPI through HDMI cable. I am surprised how well is playing, also thinking all the trouble that I get years ago with the RPI and Volumio.
Thanks Andrea for the incredible design you did!
Cheers,
Enrico
Enrico, I have made the same jump as you, from heavily tweaked DDDAC to Andrea's gig.
I have quite a comparable setup, standalone Rpi with HDMI transmitter, FIFO with Driscoll clocks, ultracap for DAC analogic Vref.
I have to admit that this setup sounds better in almost every aspect than my beloved DDDAC.
I have quite a comparable setup, standalone Rpi with HDMI transmitter, FIFO with Driscoll clocks, ultracap for DAC analogic Vref.
I have to admit that this setup sounds better in almost every aspect than my beloved DDDAC.
Is there a post or documentation from Andrea to help determine what values/types of clocks to choose for a particular DAC? There are a lot of options and I haven't seen something in one place to refer to. Thank you!
Look at his website 😉
If you favor old dac chip like tda1541, 5.xxx & 6.xxx SC cut laptech crystal is the way to go.
However with some hybrid setups like the fifoPi from IanCanada, you can mismatch the frequency and choose for the second speed a 24.xx crystal for high res material ! Very handy when you have both Red Book and High res (192 K hz) reccordings.
Hope that helps.
If you favor old dac chip like tda1541, 5.xxx & 6.xxx SC cut laptech crystal is the way to go.
However with some hybrid setups like the fifoPi from IanCanada, you can mismatch the frequency and choose for the second speed a 24.xx crystal for high res material ! Very handy when you have both Red Book and High res (192 K hz) reccordings.
Hope that helps.
Actually my mentioned DAC PCM1794 is no more the DDDAC.
It's based on PCM1794 chip but the design is completely different.
Only ONE chip per balanced channel, no more data delay, the VCC is 5V instead of 8V and the Iref is 10K as per datasheet.
The I/V converter is the SEN I/V from EUVL with floating supply with batteries.
This DAC was the huge jump for me from my previous DDDAC heavily tweaked.
As I said in my previous post, I was intrigued by the Andrea design and I decided to build it also because I was curious to compare it with my PCM.
Actually I like both, the PCM is a little more analog but it's lacking a little in the high while the LT is maybe a little more "dry" but the overall is simply amazing, really enjoyable for hours.
I have both of them in my system ready to play, 80% of the time I listen to Andrea DAC...
Attachments
which Andrea DAC ? What is LT, please ? What is the one of the picture ? Pretty red digital front end btw !