DAC 2496 (AK4393) DAC KIT With CS8416+AK4393+5532 - Page 115 - diyAudio
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Old 25th January 2012, 05:04 PM   #1141
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Quote:
Originally Posted by ClaveFremen View Post
Interesting

Did you take in account the peculiar LPF needed by AK4396 (fc=125kHz, Q=0.692)?



So, probably, FCs are not causing overheat but still, IMHO, is safer to remove them after LM1117s.

I just connect my Headphone amp WOO6 .....and listen to the music .

Did you take in account the peculiar LPF needed by AK4396 (fc=125kHz, Q=0.692)?
Can you explain me what does it mean ?

Thanks

Serge
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Old 25th January 2012, 11:14 PM   #1142
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Quote:
Originally Posted by Sergelisses View Post
Did you take in account the peculiar LPF needed by AK4396 (fc=125kHz, Q=0.692)?
Can you explain me what does it mean ?
Hi Serge,

those AKM DACs don't do the entire LP filtering on chip and they depend from the external LPF to give a straight frequency response.

AK4393/5 and AK4396 have a different external LPF (see datasheets) thus they give different frequency response which should be filtered accordingly.

In AK4396 datasheet is stated that LPF should have that cut-off frequency and that Q to have a balanced frequency response.
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Old 26th January 2012, 01:02 AM   #1143
F1 FAN is offline F1 FAN  Canada
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Quote:
Originally Posted by Sergelisses View Post

Did you take in account the peculiar LPF needed by AK4396 (fc=125kHz, Q=0.692)?
Can you explain me what does it mean ?

Thanks

Serge
Since they are noise shaping DAC's there will be a lot of noise produced above the audio band requiring the use of a low pass filter to attenuate it.The AK4396 is much better than the AK4393 in this regard so the low pass filters corner frequency can be shifted higher.
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Old 26th January 2012, 06:17 AM   #1144
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Originally Posted by F1 FAN View Post
The AK4396 is much better than the AK4393 in this regard so the low pass filters corner frequency can be shifted higher.
That filter specification came from AK4396 datasheet...
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Old 26th January 2012, 07:01 AM   #1145
pchw is offline pchw  United States
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Like other said, definitely do the following:
(1) clean up the flux with isopropyl-alcohol.
(2) Reflow some solder joins.
(3) Fix up the wrong polarity of a cap at the opamp (if you have extra cap, replace it).
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Old 26th January 2012, 07:30 AM   #1146
NebuK is offline NebuK  Germany
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CRAP, how could i overlook this? will report back later ;/
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Old 26th January 2012, 11:47 AM   #1147
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Hello, I ordered the kit (only PCB and SMD devices) and I'm ordering the components to build it with the upgrade ClaveFreemen.
I have a doubt about impedances L1 and L2. They are perhaps the Vk 200? So that if you put it in order ...
Thank you ...
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Old 26th January 2012, 03:30 PM   #1148
jimchan is offline jimchan  Norway
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Quote:
Originally Posted by ClaveFremen View Post
OK, two problems:

  • You're still using the AK4393 LPF with the AK4396 so high frequencies are exacerbated, often resulting in harshness
  • The LM4562 is overly precise and detailed on high freqs so every minimum problem with them is thrown in your face.
The first thing to do, IMHO, is changing LPF's resistors and caps.


If, after that, highs are not as refined as you like you should also change the opamp.


OPA827 is as precise as LM4562 but it hardly get harsh.

Thanks Claymen, i didn't realise I had the 4396 version. I will change the caps to the recommended and let you know the results. Fingers crossed :-)
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Old 26th January 2012, 10:20 PM   #1149
F1 FAN is offline F1 FAN  Canada
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Quote:
Originally Posted by ClaveFremen View Post
That filter specification came from AK4396 datasheet...
yes Dario i'm aware of that since I used the LPF in the datasheet on my 4396 board.My point ,though not clear was that the 4396 is claimed to have less hi frequency noise (similar to an R2R dac)than typical for a Delta-sigma dac.Therefore AKM suggest the use of a filter at a higher frequency than usual 125k .
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Old 26th January 2012, 10:30 PM   #1150
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Quote:
Originally Posted by F1 FAN View Post
Therefore AKM suggest the use of a filter at a higher frequency than usual 125k .
Maybe my English is not so good but I'm not sure that I understand the quoted sentence.

BTW the AK4396 LPF (fc =125kHz) do more than filtering HF noise (quite non-existent with AK4396), it also balance the frequency response.

Earlier in this thread I've posted two graphs that shows how different is the effect of AK4393 and AK4396 LPFs
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