The way I am looking at this - if the price of my output stage cannot be lowered (i.e. If I have to use transformers with Sabres) - then I ll at least try to get the price of the board down. Currently my DAC stage sits at nearly $700. $400 of which is the DAC board.
If I can get rid of the transformers - even better
. That is why the renewed interest with this board and opamps.
Alternatively - I can try the new AK4497 when it becomes available. Unfortunately - in my setup - Sabres are the best.
If I can get rid of the transformers - even better
. That is why the renewed interest with this board and opamps. Alternatively - I can try the new AK4497 when it becomes available. Unfortunately - in my setup - Sabres are the best.
I have tried it on PCB ver. 1.04. I have decided that it works fine. However, it totally depends on pot (namely, its characteristic). Some pots give you a good range and comfort dependence "angle-volume", some - do not.
I think that the better idea (and I plan to implement it) is using of cheap digital pot /ADC controlled by Attiny, Arduino, etc. via any potentiometer - as we can not access to MCU code on PCB let us write own table "angle-volume"
I would expect the value of the pot is not so critical as it obviously creates a divider for the MCU input? Which pots/characteristics have you tried? Is better a linear or log pot?
Yes, the value of pot does not matter. Curve type matters.
I have tried variouse pots, from 5 to 500 KOhms, and I have good results only with one pot - 50KOhms "C" (anti-log type). All other curves (log or linear) give me bad results - volume is rasing too slow first and too fast at the end of scale.
So with digital test signal and careful measurement (RVol vs. output V) it should be possible to plot out the curve and mimic it with other means, e.g. Arduino.
Hi guys,
I will like to replace AMS1117 and 7805 regulators on a 1.06 board.
Do you think this one in 5v will acheive better sq for replacing 7805?
LT3045-78xx Ultralow-noise (0.8mVrms) linear regulator 0V-15V, 0.5A, 78xx Layout | eBay
is 0.5A ok?
By wich better regulator may I replace the AMS1117?
Thank you for your help.
0.5A is definitely OK, but I am not sure if it would bring much on SQ. If I am not mistaken, the 7805 is only a pre-regulator here - so you would have premium pre-regulator followed by much noisier AMS1117 :-(. If I had LT3045 at hand, I would rather leave 7805 in place and use LT3045 in place of AMS1117, set for 3.3V. It should be possible with some fiddling.
I myself found no ultra-low noise alternative for AMS1117 in SOT223 package.
You can get some interesting info from Allo and they RELAY ATTENUATOR. It's volume control board. They board is build from discrete resistors. Resistors values and volume curve is in Excel File Relay Attenuator 10k Stereo
Indeed, there are no (ultra) low noise alternative for AMS1117 in SOT223 having the same pinout. So, just a minute ago I have replaced AMS1117 by LT1763-3.3 (soldered on soic2dip adapter). Even with this (definetely not high-end) regulator SQ became much more better. It was a small job (about 30 minutes), so, I could recommend such mod.
More, it is relatively easy to turn ES9038q2m to current mode: for I/V I have implemented circuit specified in ES9018k2m datasheet using two OPA1632 (leaving next stage as is) - also, it's not so difficult. However, I'm not sure if is it the best option.
There are many ways to skin a cat. I am aware of many of them but wanted to know if that what is already provided on the board can be reasonably used. Díky
!Thanks, Adson, for sharing this mod. LT1763-3.3 is not top with 20uV noise but it is nice to know it helps. My favorite for this position was ADM7150-3.3 with 1.6uV noise, available in the same SOIC 8pin package as LT1763.
Seems we think in same direction
!
I do not see why it should not work. If you have a heap of LT3045s at hand, set one as pre-regulator for 5V and second as post-regulator for 3.3V. It's a bit overkill and I am not sure if the SQ will be better as if you leave the 7805 in place, but it should work. Keep in mind the board has other flaws that will limit achievable SQ, though...
Hi friends,
I'm thinking of buying this ES9038Q2M Board (v1.06) and connect it directly to my Pi3 via I2S ( not via USB Amanero). I just wonder if this connection (directly from Pi3 to ES9038Q2M) can play DSD native or Dop ? Has anyone try before and give me some review?
Thank you so much !
I'm thinking of buying this ES9038Q2M Board (v1.06) and connect it directly to my Pi3 via I2S ( not via USB Amanero). I just wonder if this connection (directly from Pi3 to ES9038Q2M) can play DSD native or Dop ? Has anyone try before and give me some review?
Thank you so much !