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DAC IV stages
Yahzi
post Feb 20 2013, 18:38
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How important are DAC IV stages in the design of a DAC? I've heard they can cause audible differences. Is this true? I'm not a DAC designer, but I assume there are those who understand the technical merits. Is it a big deal?
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Mach-X
post Mar 5 2013, 11:47
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Rather ironic that everybody is rather correct. The clip+ when the rockbox firmware is installed has near infinite volume settings, that attenuate very smoothly in nature, that would suggest to me, an analog gain adjustment.

However my Galaxy cellphone with wolfson wm8994 has both digital and analog adjustment. With stock firmware the analog is locked (probably for liability reasons as the amp is quite a beast), while the digital gain is adjusted in 8 steps. With the 'voodoo' software modification, the analog amp is unlocked, and the digital amp gets locked to max signal, theoretically improving SNR, as well as EMI, as in most cases with full bit depth, you are using much less gain on the analog amp smile.gif

Really cheap pmps seem to use digital only with a fixed analog gain. So it would seem both implementations are used.
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- Yahzi   DAC IV stages   Feb 20 2013, 18:38
- - John_Siau   The I-V (current to voltage) conversion stage of a...   Feb 20 2013, 20:48
|- - Soap   QUOTE (John_Siau @ Feb 20 2013, 14:48) Fo...   Feb 21 2013, 03:37
|- - John_Siau   QUOTE (Soap @ Feb 20 2013, 21:37) QUOTE (...   Feb 21 2013, 15:20
|- - Arnold B. Krueger   QUOTE (John_Siau @ Feb 21 2013, 09:20) QU...   Feb 21 2013, 16:09
- - Yahzi   Thanks for the reply John. I'm getting a few p...   Feb 20 2013, 21:47
- - John_Siau   Designing an I-V converter with a 130 dB SNR is no...   Feb 20 2013, 22:02
|- - Yahzi   But it is largely irrelevant if it is competently ...   Feb 20 2013, 22:28
||- - benski   QUOTE (Yahzi @ Feb 20 2013, 16:28) But it...   Feb 20 2013, 22:44
|- - Arnold B. Krueger   QUOTE (John_Siau @ Feb 20 2013, 16:02) De...   Feb 21 2013, 16:11
|- - John_Siau   QUOTE (Arnold B. Krueger @ Feb 21 2013, 10...   Feb 21 2013, 16:47
- - John_Siau   Take a look at published specifications for D/A co...   Feb 20 2013, 22:52
|- - saratoga   QUOTE (John_Siau @ Feb 20 2013, 16:52) Ta...   Feb 20 2013, 23:51
||- - John_Siau   QUOTE (saratoga @ Feb 20 2013, 17:51) 80d...   Feb 21 2013, 14:57
||- - saratoga   QUOTE (John_Siau @ Feb 21 2013, 08:57) QU...   Feb 21 2013, 20:00
||- - John_Siau   QUOTE (saratoga @ Feb 21 2013, 14:00) All...   Feb 21 2013, 23:03
||- - saratoga   QUOTE (John_Siau @ Feb 21 2013, 17:03) QU...   Feb 21 2013, 23:23
|||- - John_Siau   QUOTE (saratoga @ Feb 21 2013, 17:23) QUO...   Feb 22 2013, 15:15
||||- - Arnold B. Krueger   QUOTE (John_Siau @ Feb 22 2013, 09:15) QU...   Feb 22 2013, 16:33
|||||- - saratoga   QUOTE (scuttle @ Feb 22 2013, 09:49) From...   Feb 22 2013, 17:58
|||||- - scuttle   QUOTE (saratoga @ Feb 22 2013, 16:58) QUO...   Feb 22 2013, 19:01
|||||- - saratoga   QUOTE (scuttle @ Feb 22 2013, 13:01) No. ...   Feb 22 2013, 19:39
||||||- - John_Siau   QUOTE (saratoga @ Feb 22 2013, 13:39) Wel...   Feb 22 2013, 20:13
||||||- - saratoga   QUOTE (John_Siau @ Feb 22 2013, 14:13) Bo...   Feb 22 2013, 20:36
||||||- - John_Siau   QUOTE (saratoga @ Feb 22 2013, 14:36) Lik...   Feb 22 2013, 20:46
||||||- - saratoga   QUOTE (John_Siau @ Feb 22 2013, 14:46) QU...   Feb 22 2013, 20:53
||||||- - John_Siau   QUOTE (saratoga @ Feb 22 2013, 14:53) Roc...   Feb 22 2013, 21:13
||||||- - saratoga   QUOTE (John_Siau @ Feb 22 2013, 15:13) QU...   Feb 22 2013, 21:38
|||||||- - John_Siau   QUOTE (saratoga @ Feb 22 2013, 15:38) The...   Feb 22 2013, 22:21
|||||||- - saratoga   QUOTE (John_Siau @ Feb 22 2013, 16:21) Bu...   Feb 22 2013, 22:24
|||||||- - John_Siau   QUOTE (saratoga @ Feb 22 2013, 16:24) QUO...   Feb 22 2013, 22:38
|||||||- - greynol   QUOTE (John_Siau @ Feb 22 2013, 13:38) So...   Feb 22 2013, 22:48
||||||||- - John_Siau   QUOTE (greynol @ Feb 22 2013, 16:48) Is t...   Feb 22 2013, 22:57
||||||||- - greynol   QUOTE (John_Siau @ Feb 22 2013, 13:57) Ye...   Feb 22 2013, 23:05
|||||||- - saratoga   QUOTE (Arnold B. Krueger @ Feb 22 2013, 17...   Feb 23 2013, 04:02
|||||||- - Arnold B. Krueger   QUOTE (saratoga @ Feb 22 2013, 22:02) Loo...   Feb 23 2013, 17:11
|||||||- - John_Siau   QUOTE (Arnold B. Krueger @ Feb 23 2013, 11...   Feb 27 2013, 15:10
|||||||- - Arnold B. Krueger   QUOTE (John_Siau @ Feb 27 2013, 09:10) In...   Feb 27 2013, 16:30
||||||||- - John_Siau   QUOTE (Arnold B. Krueger @ Feb 27 2013, 10...   Mar 4 2013, 17:28
||||||||- - Soap   QUOTE (John_Siau @ Mar 4 2013, 11:28) QUO...   Mar 5 2013, 01:11
|||||||- - Nessuno   QUOTE (John_Siau @ Feb 27 2013, 15:10) Wh...   Feb 28 2013, 13:57
||||||- - Arnold B. Krueger   QUOTE (John_Siau @ Feb 22 2013, 15:13) An...   Feb 22 2013, 22:56
||||||- - John_Siau   QUOTE (Arnold B. Krueger @ Feb 22 2013, 16...   Feb 22 2013, 23:06
|||||- - greynol   QUOTE (scuttle @ Feb 22 2013, 10:01) That...   Feb 22 2013, 19:42
|||||- - Arnold B. Krueger   QUOTE (greynol @ Feb 22 2013, 13:42) QUOT...   Feb 22 2013, 20:36
|||||- - greynol   QUOTE (Arnold B. Krueger @ Feb 22 2013, 11...   Feb 22 2013, 20:43
||||- - saratoga   QUOTE (John_Siau @ Feb 22 2013, 09:15) Wr...   Feb 22 2013, 17:48
|||- - scuttle   QUOTE (saratoga @ Feb 21 2013, 22:23) QUO...   Feb 22 2013, 15:49
||- - Arnold B. Krueger   QUOTE (John_Siau @ Feb 21 2013, 17:03) QU...   Feb 22 2013, 16:10
||- - John_Siau   QUOTE (Arnold B. Krueger @ Feb 22 2013, 10...   Feb 22 2013, 19:41
|- - Arnold B. Krueger   QUOTE (John_Siau @ Feb 20 2013, 16:52) Ta...   Feb 21 2013, 16:00
||- - John_Siau   QUOTE (John_Siau @ Feb 20 2013, 16:52) Ta...   Feb 21 2013, 18:44
|||- - [JAZ]   QUOTE (John_Siau @ Feb 21 2013, 18:44) sy...   Feb 21 2013, 20:36
|||- - John_Siau   QUOTE ([JAZ] @ Feb 21 2013, 14:36...   Feb 21 2013, 22:49
|||- - [JAZ]   That the usual listening volume of most electronic...   Feb 21 2013, 23:45
|||- - Arnold B. Krueger   QUOTE (John_Siau @ Feb 21 2013, 16:49) QU...   Feb 22 2013, 16:27
|||- - John_Siau   QUOTE (Arnold B. Krueger @ Feb 22 2013, 10...   Feb 22 2013, 18:17
|||- - John_Siau   The following quote from NwAvGuy's Sansa Clip+...   Feb 22 2013, 18:32
|||- - saratoga   QUOTE (John_Siau @ Feb 22 2013, 12:17) In...   Feb 22 2013, 18:40
||||- - John_Siau   QUOTE (saratoga @ Feb 22 2013, 12:40) I...   Feb 22 2013, 19:10
||||- - saratoga   QUOTE (John_Siau @ Feb 22 2013, 13:10) QU...   Feb 22 2013, 19:45
||||- - John_Siau   QUOTE (saratoga @ Feb 22 2013, 13:45) I d...   Feb 22 2013, 20:38
||||- - saratoga   QUOTE (John_Siau @ Feb 22 2013, 14:38) QU...   Feb 22 2013, 20:42
|||- - Arnold B. Krueger   QUOTE (John_Siau @ Feb 22 2013, 12:17) Bu...   Feb 22 2013, 20:58
|||- - saratoga   QUOTE (Arnold B. Krueger @ Feb 22 2013, 14...   Feb 22 2013, 21:07
|||- - Arnold B. Krueger   QUOTE (saratoga @ Feb 22 2013, 15:07) QUO...   Feb 22 2013, 23:01
||- - Ethan Winer   QUOTE (Arnold B. Krueger @ Feb 21 2013, 10...   Feb 21 2013, 20:43
|- - Arnold B. Krueger   QUOTE (John_Siau @ Feb 20 2013, 16:52) D/...   Feb 21 2013, 16:04
|- - John_Siau   QUOTE (Arnold B. Krueger @ Feb 21 2013, 10...   Feb 21 2013, 16:28
|- - Arnold B. Krueger   QUOTE (John_Siau @ Feb 21 2013, 10:28) QU...   Feb 21 2013, 18:28
- - Yahzi   So your view is that it is a potential issue but i...   Feb 20 2013, 23:09
- - saratoga   I think SNR is probably not the best way to think ...   Feb 22 2013, 00:05
- - greynol   Since when has NwAvGuy been the ultimate arbiter o...   Feb 22 2013, 18:53
|- - scuttle   QUOTE (greynol @ Feb 22 2013, 17:53) Sinc...   Feb 22 2013, 19:08
|- - greynol   QUOTE (scuttle @ Feb 22 2013, 10:08) You...   Feb 22 2013, 19:18
- - greynol   So rockbox uses the analog volume control, which i...   Feb 22 2013, 20:27
- - greynol   1) 6 dB is not 20 dB 2) Downward scaling in order...   Feb 22 2013, 21:30
- - Mach-X   Rather ironic that everybody is rather correct. Th...   Mar 5 2013, 11:47


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