Well here is a good start from the datasheet, we just need to find appropriate opamps and package size to fit the three spots on the board, there will be some jumpering. trace cutting but I think this would be worth the effort. Unfortunately I am not up to speed on opamps for V-out S-D dacs, So any recommendations would be appreciated. This would also give balanced and proper unbalanced outputs.
Can you take some pics of the boards, especially the top and bottom of the main DAC?
I ordered late, so I am still waiting for my boards to show up.
Randy
Information directly from Priyesh
Just everyone can use the data
MAIN DAC BOARD
74HCU04 IC1 SOIC14
PCM2707 IC2 32-TQFP
74HC157 IC3 SO1
SRC4192/AD1896 IC4 SSOP28
WM8741/WM8742 IC5 SSOP28
OPA2365 IC6 SO-8
SN74AHC1G08 IC7 SOT23-5
SN74AHC1G14 IC8 SOT23-5
AD8656/AD8532 IC9 SOIC8
LP2992 REG 1,2,3,4,5 SOT23-5
TPS3809K33 RST SOT-23
DIGITAL RECEIVER 1
DIR9001 IC TSSOP28
DIGITAL RECEIVER 2
WM8804 IC SSOP20
Thanks
Do
Just everyone can use the data
MAIN DAC BOARD
74HCU04 IC1 SOIC14
PCM2707 IC2 32-TQFP
74HC157 IC3 SO1
SRC4192/AD1896 IC4 SSOP28
WM8741/WM8742 IC5 SSOP28
OPA2365 IC6 SO-8
SN74AHC1G08 IC7 SOT23-5
SN74AHC1G14 IC8 SOT23-5
AD8656/AD8532 IC9 SOIC8
LP2992 REG 1,2,3,4,5 SOT23-5
TPS3809K33 RST SOT-23
DIGITAL RECEIVER 1
DIR9001 IC TSSOP28
DIGITAL RECEIVER 2
WM8804 IC SSOP20
Thanks
Do
Its been a while since I did smd chips like these (been in tube world too long.) I used to use a low temp solder from Tangent with SSop-28 fairly easily but he no longer sells it. It makes installing these little chips a breeze for anyone.
anyone know where to get the tangent low temp solder for smd work?
(yes I know its technically not as good to use a eutectic solder for boards destined for the military, nasa, etc but for this DAC I think it will be fine)
anyone know where to get the tangent low temp solder for smd work?
(yes I know its technically not as good to use a eutectic solder for boards destined for the military, nasa, etc but for this DAC I think it will be fine)
I guess I'm dense, but I'm not sure how low temp solder helps to install SMD chips? I see people use low temp solder for removing parts.
BTW, low temp solder seems to be easy to find, not sure if there was anything special about Tangents. I would guess maybe not, and that's why he no longer sells it.
A good magnifying glass (I have a headband kind) really helps, along with a very fine tip for your iron. Also, some fine solder braid, so if you get bridges you can remove them.
Before you're done, you may find that the little regs and gates are harder to install then the bigger IC's.
BTW, general comment, you guys may want to buy spares of the little parts, it's easy to push too hard on them when you are trying to hold them down, and send these little guys flying somewhere.
Randy
Voltage Regs
Thought I would share my thoughts on the voltage regs, and how they are used.
In the DAC, there are two 5VDC regs, and five 3.3VDC regs.
The first 5V reg powers the HC04, HC157, Oscillator and analog section of 8741. Each device has it’s own ferrite bead to isolate it, but power still comes from one reg.
The 2nd 5V reg powers opamp, headphone amp and HCg14.
So, since I am planning to remove the opamp and headphone amp, the 2nd reg would just power the HCg14. This gate is used to drive one of the LED’s. I don’t like having all of that stuff on the first reg, so I plan to put the oscillator on this reg.
At first, I want to use this as a USB DAC, and not use SPDIF or I2S inputs.
As such, I am not really using the HC04, and don’t need to HC157. The HC04 buffers the SPDIF input, and the HC157 selects the i2S datastream. I may choose to not install the 157, or the HC04. This would leave the analog 8741 on its own regulator, and the oscillator on its own regulator, which I think is ideal. My goal is for each IC to have it’s own regulator, so if I do add the HC04 and HC157 later, I would probably add a couple more regs for them too.
For the 3.3V regs, the first one powers the PCM2707 and the g08. The g08 just generates a status signal which I don’t think switches state, so I think it is OK to leave both parts on this reg
The 2nd 3.3 reg powers the daughtercard.
The 3rd 3.3 reg powers the SRC4192.
The 4th 3.3 reg powers the RST chip.
The 5th 3.3 reg powers the logic part of the WM8741.
So, 3.3 power seems very well done (IMHO), one reg for every chip, except the first set, where it should be fine.
One last comment about power. I have read part of the long buffalo dac threads, and power is a big deal for that DAC. Wondering how much affect it would have on the sound if you provided separate regs different parts of the DAC?
One more last comment.
I may try a better reg, something like this
Shunt reg
I have seen the Thorsten design this was based on, and had planned to use that, but this may be an improved, albeit slightly more complicated version of Thorsten's simple shunt reg.
Randy
Thought I would share my thoughts on the voltage regs, and how they are used.
In the DAC, there are two 5VDC regs, and five 3.3VDC regs.
The first 5V reg powers the HC04, HC157, Oscillator and analog section of 8741. Each device has it’s own ferrite bead to isolate it, but power still comes from one reg.
The 2nd 5V reg powers opamp, headphone amp and HCg14.
So, since I am planning to remove the opamp and headphone amp, the 2nd reg would just power the HCg14. This gate is used to drive one of the LED’s. I don’t like having all of that stuff on the first reg, so I plan to put the oscillator on this reg.
At first, I want to use this as a USB DAC, and not use SPDIF or I2S inputs.
As such, I am not really using the HC04, and don’t need to HC157. The HC04 buffers the SPDIF input, and the HC157 selects the i2S datastream. I may choose to not install the 157, or the HC04. This would leave the analog 8741 on its own regulator, and the oscillator on its own regulator, which I think is ideal. My goal is for each IC to have it’s own regulator, so if I do add the HC04 and HC157 later, I would probably add a couple more regs for them too.
For the 3.3V regs, the first one powers the PCM2707 and the g08. The g08 just generates a status signal which I don’t think switches state, so I think it is OK to leave both parts on this reg
The 2nd 3.3 reg powers the daughtercard.
The 3rd 3.3 reg powers the SRC4192.
The 4th 3.3 reg powers the RST chip.
The 5th 3.3 reg powers the logic part of the WM8741.
So, 3.3 power seems very well done (IMHO), one reg for every chip, except the first set, where it should be fine.
One last comment about power. I have read part of the long buffalo dac threads, and power is a big deal for that DAC. Wondering how much affect it would have on the sound if you provided separate regs different parts of the DAC?
One more last comment.
I may try a better reg, something like this
Shunt reg
I have seen the Thorsten design this was based on, and had planned to use that, but this may be an improved, albeit slightly more complicated version of Thorsten's simple shunt reg.
Randy
I plan to start with transformers, but if those don't work out, will add an active stage.
Aikido has a balanced to SE circuit, if you want a glow in your dac.
Even if I use solid state, I would probably do the output stage on a seperate board, I think it would be easier than trying to mod the board for a different circuit, but I could be wrong.
Randy
Last post of the night
.I have been working on a Mouser BOM.
I got to the through hole caps, and measured the lead pitch on them.
There are 4 sizes, 2, 2.5, 3.5 and 5 mm lead pitch. Not sure if you knew this when you picked your caps?
For example,
C56 is 2mm
C16 is 2.5mm
C7 is 3.5mm
C60 is 5mm
Randy
Last post of the night
I have been working on a Mouser BOM.
I got to the through hole caps, and measured the lead pitch on them.
There are 4 sizes, 2, 2.5, 3.5 and 5 mm lead pitch. Not sure if you knew this when you picked your caps?
For example,
C56 is 2mm
C16 is 2.5mm
C7 is 3.5mm
C60 is 5mm
Randy
The MKPs I made a conversion using the picture, so yes I have taken this into account. For as long as my conversions were right...
The smd components are 0805 which is standard, so it should be good. Kept all resistors at 0.1% tolerance for good matching.
I will probably skip the I2S logic but wouldn't mind keeping the spdif for connecting to older cd players. USB is a must!
Keep us informed and please PM me your BOM or simply post it when you're done.
I'm thinking doing it the same as yours.
Ciao!
Do
Finished my BOM, not going to share, as it contains a list of elements available from local "non-line" shops. Went for 1% resistors (close examination of schematics does not reveal critical parts where close matching is a must), replaced some ELNAs to Sanyo, Sanyo for Rubycon, etc. depending on availabality. On this stage I cannot decide either to skip the whole headphone amp part or to change the volume pot to stereo, without switch, and leave the power supply for headphone amp always ON. The only source for ALPS listed in original BOM is Mouser, and the shipping for one pot to LV is 40 EUR
shops. Went for 1% resistors (close examination of schematics does not reveal critical parts where close matching is a must), replaced some ELNAs to Sanyo, Sanyo for Rubycon, etc. depending on availabality. On this stage I cannot decide either to skip the whole headphone amp part or to change the volume pot to stereo, without switch, and leave the power supply for headphone amp always ON. The only source for ALPS listed in original BOM is Mouser, and the shipping for one pot to LV is 40 EUR
Finished my BOM, not going to share, as it contains a list of elements available from local "non-line"
Hi tornislv,
As posted under my bom, here's three places where you can get it
1 ALPS RK0971221Z05 Tangent’s Parts Shop $2.75 $2.75
AMB audio shop $3.25 $3.25 under "Panel components"
RK0971221Z05 ALPS Potentiometers $3.06 $3.06
Ciao!
Do
Selling my boards
Guys and Gals,
I'm selling my boards... Unfortunately, I have to back off a little... I have 6 other projects queued up and this is just going to add to the pile. I need to be able to finish those projects and put them in nice boxes, not just keep them on a piece of plywood!
If anyone is interested, I have the main board, and the wolfson receiver with the mini logic converter.
I'll let everything go for 30$ US plus shipping...
I have not received the boards yet but will let you know when I do...
Any takers? Just PM me
Ciao!
Do
Guys and Gals,
I'm selling my boards... Unfortunately, I have to back off a little... I have 6 other projects queued up and this is just going to add to the pile. I need to be able to finish those projects and put them in nice boxes, not just keep them on a piece of plywood!
If anyone is interested, I have the main board, and the wolfson receiver with the mini logic converter.
I'll let everything go for 30$ US plus shipping...
I have not received the boards yet but will let you know when I do...
Any takers? Just PM me
Ciao!
Do
I'm getting kind of close to finishing a mouser bom, been delayed because of work and some other issues. I am currently only really worried about the main board, and I only plan to build the level converter daughterboard right now. You need this to connect a 5V arduino board to this DAC.
I'll post what I have pretty soon, there's a few caps I need to find. It will probably be missing some headers/connnectors/jacks, which I may not use.
Randy
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