Hi,
it seems that the 3dB gap is due to the Gain setup, not Load (GC bits, not HLOAD bit), those are two different parameters.
One thing to spot: all the measurements and official figures in the datasheet are given with HLOAD=0 (load max = 8K). But sometime, tests conditions are optimized to give the best figures, which may not be the bests for SQ.
I just went quickly through the DS. See page 91, there's a (short ! ) description of the SC0,1 bits which configure SQ, there're related to 'internal current'. Maybe those bits change internal config of the dac out stage resulting in a change in SQ (but to be defined...), you will also notice that SC2 is called 'High Sound Quality Mode'...so this will be my default setup
Thanks a lot for your input. These are the areas where the AK4497 differs from its 4490 and 4495 siblings and this is where some of the higher costs and performance of the AK4497 comes in.
My plan now is to set it up for:
HLOAD=1(Heavy Load)
SC=0,1 (Maximum internal analogue current, High sound quality mode)
GC=1 (3.75 Vpp Output)
I think this is the best technically performing configuration and should give a very good improvement over default - at least 3dB!
Unfortunately, I could not get any output at all from the boards, not even in pin mode (with ACKS & PSN pins set high) so this thing is on hold for the time being. I have been using an Amanero board and the AK4490 boards slide in and work very well whereas the AK4497 do not. If anybody has any ideas, please let me know.
I do. I oredered them and ... the did not work
I have the same ak4497 board. I had the same problem and found that you need to connect/power up the 3 pin PS (15/gnd/-15V) first before the 2pin AC input.
Good to know, but how to get the ignition delay, if you use only one transformer and the power + -15v passes through an AC-DC converter and regulator and 9v AC power is directly connected to the DAC.
Apart from this problem, how is the sound with this DAC?
I do. I oredered them and ... the did not work
It didn't work for me either and I assumed that my I2S USB Interface was at fault and that the signal was not locking. I will give the suggested sequence of powering up a try and see if that helps. Unfortunately it seems impossible to get any technical help from the sellers so if people could share any information they have, it would be appreciated.
Hi Themystical,
I don’t know if it’s help, but the 4497 has a power up sequence described in the DS, page 10 :
‘Note 7. TVDD and AVDD must be connected to the same ground plane and powered up at the same time. When not using the LDO (LDOE pin = “L”), all power supplies (DVDD (1.8V), TVDD and AVDD (3.3V) and VDDL/R (5V)) should be powered up at the same time or sequentially in the order of 3.3V (TVDD, AVDD), 1.8V (DVDD) and 5V (VDDL/R).
Note 8. The internal LDO outputs DVDD (1.8V) when the LDOE pin = “H”. 3.3V (TVDD and AVDD) power supplies must be powered up before or at the same time with 5V (VDDL/R) power supplies when the LDOE pin = “H”.’
In other words, it can be said that VDDL / R should not be turned on before other supplies (TVDD, AVDD and DVDD) regardless of the use of the internal LDO. VDDL/R is the supply of the output stage of the DAC.
That may explain ChuckT solution in post #365 if we make the assumption that the AC input of his board is used to provide the analog supply (VDDL/R, probably Vref and OpAmp supplies). With this assumption, providing AC supply after the one on 3 pin connector give compliance with the power up scheme given by Note 7 & 8.
Chris
I don’t know if it’s help, but the 4497 has a power up sequence described in the DS, page 10 :
‘Note 7. TVDD and AVDD must be connected to the same ground plane and powered up at the same time. When not using the LDO (LDOE pin = “L”), all power supplies (DVDD (1.8V), TVDD and AVDD (3.3V) and VDDL/R (5V)) should be powered up at the same time or sequentially in the order of 3.3V (TVDD, AVDD), 1.8V (DVDD) and 5V (VDDL/R).
Note 8. The internal LDO outputs DVDD (1.8V) when the LDOE pin = “H”. 3.3V (TVDD and AVDD) power supplies must be powered up before or at the same time with 5V (VDDL/R) power supplies when the LDOE pin = “H”.’
In other words, it can be said that VDDL / R should not be turned on before other supplies (TVDD, AVDD and DVDD) regardless of the use of the internal LDO. VDDL/R is the supply of the output stage of the DAC.
That may explain ChuckT solution in post #365 if we make the assumption that the AC input of his board is used to provide the analog supply (VDDL/R, probably Vref and OpAmp supplies). With this assumption, providing AC supply after the one on 3 pin connector give compliance with the power up scheme given by Note 7 & 8.
Chris
I use the dac with a wooden open box. I use the existing connector with batteries and plug in the +/-15V first and then the AC part (I remove the rectifier and feed DC 6.5V direct)
I did not use the opamp stage and using 2 audio transformer connect to ak4497 for filtering and direct out.
The power supply all batteries with Lifepo4 for 6.5v for 15v input and another 6.5V for AC input (with rectifier removed)
Sound is very good. (battery ak449x is my main dac and I have a Soekris R2R board and a number of other dac sitting unused
)
Hello, what config do you have on transformers?... i tried sowter 600:600 on mine with some resistors and without resistors on secondary side.. and i couldn t have it to sound right....I use the dac with a wooden open box. I use the existing connector with batteries and plug in the +/-15V first and then the AC part (I remove the rectifier and feed DC 6.5V direct)
I did not use the opamp stage and using 2 audio transformer connect to ak4497 for filtering and direct out.
The power supply all batteries with Lifepo4 for 6.5v for 15v input and another 6.5V for AC input (with rectifier removed)
Sound is very good. (battery ak449x is my main dac and I have a Soekris R2R board and a number of other dac sitting unused
Do you feed 6.5v on dac vref? Maxim on datasheet is 5.25v...
I used super v/i converter based on Lundahl (ll1684) transformers for ak4490 with success.
You could actually used bare Lundahl for this without any caps and resistors as well.
However it seems that with this ak4497 board you still have to power it with +/-/15V...
When I tried this board ak4497 with those Lundahl trafos and power only 6.5V (no -/+15V) I could not get sound out of it.
I need to try powering it with -/+15V also.
It's easy to introduce a delay with a relay switching the 9VAC line and powered by the +15V. If the mechanical delay is too short, add an electronic one made by a RC, Zener and transistor to drive the relay.
There are two lt1763 (5V and 3.3V) regulator on board for the +15v input. I just input 6.5v before those regulators.
Not sure why your tranny don't work. My transformer setting nothing connects to ground except preamp ground at end of output cable.
Ok tks...
You don t have any resistor on primary or secondary side of the transformer?
Are connecting direct from akm chip to the transformers or you connect chip to balanced stage and then to transformers?
I have tried powering up in this sequence and there is still no sound from my board. Can somebody who has this board confirm the behavior of the two led's on the board. When the board is powered up LED 'm' comes on but goes off shortly. I presume this is the mute led and is on when the sound is muted. The second LED on the board LED 'c' comes on power on and stays on for perhaps a minute and then goes off. Not sure what this is for. Does anybody know? Should this LED be on or off for sound?
Did you check all the jumper settings according to the ebay ak4497 board setting.
Also, I was using a Xmos xu208 USB board before and yesterday I tried an Amanero USB board and I couldn't get sound from it. I have to test again later because it would be very odd if Amanero is incompatible.
I only have K7 and K8 linked, the rest are open. Only interested in PCM and trying to get sound rather than play about with filters etc. Does this tally with your settings? Also the 'Vol' control link is as shown in the picture below.
I am using the Amanero too and actually this is the third AK4497 Board I have tried with it but getting no sound with any of them so I have asked in the Amanero thread if anybody has ever got it working with an AK4497. I will try it with an XMOS board when it arrives on the slow boat from China.
AK4497 Board Jumpers by themystical2012, on Flickr@themystical
Please, you can post some other photos of the card, because on those published on ebay, you do not see all the components very well. Thank you
But what does this mean "AK4497 board with mute function, with the Italian interface can be achieved without noise for the DSD!", Which is this "Italian interface"
Please, you can post some other photos of the card, because on those published on ebay, you do not see all the components very well. Thank you
But what does this mean "AK4497 board with mute function, with the Italian interface can be achieved without noise for the DSD!", Which is this "Italian interface"
I believe it means Amanero so I assume it is tested with it but I cant seem to make it work.
I don't have a proper camera so this is the best I can do. The only difference from stock are the Sanyo Oscons on the +-15V supply to the Opamps.
AK4497 Ebay Board by themystical2012, on Flickr- Status
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