Did you see Hifidino's latest blog where he says his WM8741 code never worked! Something about 8bit registers being sent as 7-bit. He said the controller will go thru the motions but nothing really changes, this is like 2 years after the fact
If you notice the commercial assembled Wieliang version of this DAC7 is software controlled (its the $350 oe seen on ebay, sold by Valaab also). You can pick all 5 filters at each samplerate, however the reviews I've read say they can't hear a difference in filters. Makes me wonder if Wielang is using a copy of the faulty Hifidino code
Regardless the DAC7 board software controlled would be a real nice setup, just wish the usb module did 176.4 kHz.
I am going to write my own 8741 from scratch, so I'm actually avoiding looking at other sources
I don't think the dac7 is software controllable in its present form. the pins are hardwired to hw-mode. there's no port for i2c or anything. maybe the dual 8741 is on some other board with a controller, but this one is hw-only and there's no easy way to adapt it (hack it, yes, but not meant for it by design).
for usb, I am perfectly happy with usb/spdif and then taking spdif in via any old dac. the usb audio widget or other will handle that task. embedding usb on a dac seems wrong to me; like combining things that would really better be left as their own boxes.
the usb to spdif converter is almost more part of the pc, in my view, than part of the dac. and my HTPC that is at least 2 yrs old has spdif-out on the mainboard and its bit-perfect (they all are, these days, to be dts/dd5.1 compliant) and it runs up to 192k.
the problem with the wolfson spdif receiver in hw-mode, though, is that it won't pick up 176k. the rest SRs should be ok but 176 can't be told from 192 when the chip tries. you have to tell the chip to try one, see if its locked on and if not, try the other. or 'know' via other means what rate it is and then tell the receiver chip to set its pll's and dividers as such.
I don't think the dac7 is software controllable in its present form. the pins are hardwired to hw-mode. there's no port for i2c or anything. maybe the dual 8741 is on some other board with a controller, but this one is hw-only and there's no easy way to adapt it (hack it, yes, but not meant for it by design).
for usb, I am perfectly happy with usb/spdif and then taking spdif in via any old dac. the usb audio widget or other will handle that task. embedding usb on a dac seems wrong to me; like combining things that would really better be left as their own boxes.
the usb to spdif converter is almost more part of the pc, in my view, than part of the dac. and my HTPC that is at least 2 yrs old has spdif-out on the mainboard and its bit-perfect (they all are, these days, to be dts/dd5.1 compliant) and it runs up to 192k.
the problem with the wolfson spdif receiver in hw-mode, though, is that it won't pick up 176k. the rest SRs should be ok but 176 can't be told from 192 when the chip tries. you have to tell the chip to try one, see if its locked on and if not, try the other. or 'know' via other means what rate it is and then tell the receiver chip to set its pll's and dividers as such.
I can answer that about the dac7, but not about dac5 (don't have dac5).
source is changed via a switch. its not even a logic switch but data actually goes thru it. not the best idea, really.
usb feeds i2s in. the riser module has access to i2s bus, so that's clear.
I would avoid the cmedia 'high speed' modules for now. there are new ones (fixed ones!) coming out soon and cmedia needs more time to be production quality. my 2cents...
I would handle usb/spdif outside this dac. then simply send in spdif from your external usb adapter.
spdif is not a problem and the whole world uses it. no need to go i2s when spdif is a perfectly usable interconnect.
source is changed via a switch. its not even a logic switch but data actually goes thru it. not the best idea, really.
usb feeds i2s in. the riser module has access to i2s bus, so that's clear.
I would avoid the cmedia 'high speed' modules for now. there are new ones (fixed ones!) coming out soon and cmedia needs more time to be production quality. my 2cents...
I would handle usb/spdif outside this dac. then simply send in spdif from your external usb adapter.
spdif is not a problem and the whole world uses it. no need to go i2s when spdif is a perfectly usable interconnect.
yes, they set the dac hardware filter flags, relating to samplerate range.
2 since one is for each dac chip.
there should have been more switches. anti-clip, for one. pin26 is left floating or grounded and I prefer to have the 2db anti-clip feature on, so that means lifting or never soldering down pin26 of the 8741 chip.
2 since one is for each dac chip.
there should have been more switches. anti-clip, for one. pin26 is left floating or grounded and I prefer to have the 2db anti-clip feature on, so that means lifting or never soldering down pin26 of the 8741 chip.
Hi Weiliang!
I bought DAC7 v.1.0.
I ask you to send me a diagram of versions 1.0 and 1.1.
I want to see the changes and make revisions.
My email maxlabt@mail.ru
Thank you.
I bought DAC7 v.1.0.
I ask you to send me a diagram of versions 1.0 and 1.1.
I want to see the changes and make revisions.
My email maxlabt@mail.ru
Thank you.
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I am going to write my own 8741 from scratch, so I'm actually avoiding looking at other sources
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Well do share. I would love to see a full I2C control for the wolfson, its a shame no one has really put the effort into this fine sounding dac chip that it deserves.
I might do some of the code; or AMB might do the coding. I know he's planning a DIY dac of his own and I know, for certain, that it will be open-source arduino based.
one way or another, some code will get out there and people will be able to play.
Hi linuxworks,
I have a question concerning the DAC-7 kit you built. Were the SMD-parts already assembled and only the standard parts needed to be soldered? Or is it a plain PCB and all parts (incl. SMD) need to be assembled?
I'm asking because I never soldered SMD-parts before and I'm not sure if I want to start learning it with this circuit.
Greets
Sven
I have a question concerning the DAC-7 kit you built. Were the SMD-parts already assembled and only the standard parts needed to be soldered? Or is it a plain PCB and all parts (incl. SMD) need to be assembled?
I'm asking because I never soldered SMD-parts before and I'm not sure if I want to start learning it with this circuit.
Greets
Sven
on mine, I asked for a fully unsoldered kit. I don't know what the default kit is. I think you can ask to have the smd parts soldered on but I'm not 100% sure.
the built-price is so close, maybe you should just buy the working version? the parts will be tested, no mistakes should be made and it would be easiest that way. one of mine was built and it also helped me assemble the kits that I also bought.
if you do try to solder the chips, USE LOTS OF FLUX. get a jar of amber color flux and practice on some junk boards with it. flux flux flux. that's really the secret.
the built-price is so close, maybe you should just buy the working version? the parts will be tested, no mistakes should be made and it would be easiest that way. one of mine was built and it also helped me assemble the kits that I also bought.
if you do try to solder the chips, USE LOTS OF FLUX. get a jar of amber color flux and practice on some junk boards with it. flux flux flux. that's really the secret.
Did you see Hifidino's latest blog where he says his WM8741 code never worked! Something about 8bit registers being sent as 7-bit. He said the controller will go thru the motions but nothing really changes, this is like 2 years after the fact
If you notice the commercial assembled Wieliang version of this DAC7 is software controlled (its the $350 oe seen on ebay, sold by Valaab also). You can pick all 5 filters at each samplerate, however the reviews I've read say they can't hear a difference in filters. Makes me wonder if Wielang is using a copy of the faulty Hifidino code
Regardless the DAC7 board software controlled would be a real nice setup, just wish the usb module did 176.4 kHz.
I think I said I was going to review the code. The volume part always worked. The OSF part worked. The filters, I couldn't tell... but most other people can't tell either
. Linuxworks stuff is always good. He is a professional coder . Since my wm8741 still in the drawer, no motivation to review...
PS: I think i did test the filters once with my kids (much better HF hearing) and they were able to tell the apodizing and non-apodizing filters apart when playing a high frequency test tone...
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Thanks. I think I'll ask for a semi-assembled version with the SMD-parts already soldered. If this is not possible I'll take the easy way
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fwiw, I've never been able to tell the diff in the a/b/c filter switch, either
I think that is mostly a non-feature, if you ask me.
now, anti-clip, THAT is worth its weight on gold. with so many outputs not reaching 0 at frequent peaks, the 2db cut-back can really help. I'm not sure I'd even disable it, I hard wired my dacs to always run in anti-clip mode (lift the right pin and let it float and its that easy, when in hardware mode).
I think that is mostly a non-feature, if you ask me.
now, anti-clip, THAT is worth its weight on gold. with so many outputs not reaching 0 at frequent peaks, the 2db cut-back can really help. I'm not sure I'd even disable it, I hard wired my dacs to always run in anti-clip mode (lift the right pin and let it float and its that easy, when in hardware mode).
I have had the DAC 7 for a while now. Was not really impressed. Sound is not bad but also nothing to get excited about.
Today I changed the opamps for the OP627. WOW!
Now it is someting to get excited about! Really very nice.
yes, upgrade the opamps makes a big difference