Any good TDA1541A DAC kit?

[erin]

Please provide a link to the user manual. I will check it out.
No I didn't read all 100 pages of the thread.

[qusp]

user manual comes with purchase, patience will be required for that, its sold as PCB only so you cant expect too much. it also has decent onboard regulation for both sides. input side can take a 5v from amanero, the output side should take power and ground from the destination. There is not much current needed on the output side, so taking it from the pre-reg supplying the clocks should be doable, that will keep loop area at that end to a minimum.

it was only intended as a small GB to get the price down a bit for production, response was well beyond expectations. There will without a doubt be people who bought it who have not much idea how to use it, but thats par for the course here these days.

[erin]

Ok. Thank you. I presume using u.fl connectors for i2s connections necessitates the user to design a bespoke DAC PCB to interface with this board?
Is there a proper way to retrofit u. fl connectors to an existing board? Seems a bit tricky. The other thing that interests me is that they are a 75ohm controlled impedance connector, so does this mean you need terminating resistors on your i2s lines?

[Tazzz]

Originally Posted by erin

Due to ground bounce, I suspect feeding TDA1541 with extra data bits will create additional current pulses which wont be optimal for this 16 bit chip. I am aware that the additional bits will be "ignored" Anyone want to comment?

If those extra bits are not zero the implementation is wrong... or at least not optimal.

[Tazzz]

Originally Posted by qusp

you havent even looked at the design i'm talking about have you? or at least you havent understood it. it uses u.fl connectors, like fifo, like the board presented in this thread, like anyone listening to the community and testing should be and it plugs directly onto amanero. no flying wires required. there is room for a couple control signals on the board too, amanero has functionality you arent aware of.... isolated control signals to tell clocks to change are completely doable, no need to use the amanero clocks at all

oh I wasnt aware you were catering only for the lowest common denominator that doesnt know how to use the things they buy.....

Where can more information be found about these undocumented features in the amanero?

[qusp]

no hes asking about amanero, i'm talking about the reclocker board, the extra features for the amanero and control signals are available through an editor which is also where you load new firmware I think, but yes I doubt you'll get anything without being an owner

[s3tup]

I have the anamero in front of me, with schematics. There is no manual nor any mention of slaved operation.
Oh, I may write my firmware for cpld, that's interesting! I need to reverse engineer the communication between mcu and cpld first, yet cpld is 32 cell device, should be an easy task. Then I'll be able to implemeent a bit of "drive nos" thing in the board, with extra bit reductions etc.

Sounds like a fun project!

[qusp]

Originally Posted by erin

Ok. Thank you. I presume using u.fl connectors for i2s connections necessitates the user to design a bespoke DAC PCB to interface with this board?
Is there a proper way to retrofit u. fl connectors to an existing board? Seems a bit tricky. The other thing that interests me is that they are a 75ohm controlled impedance connector, so does this mean you need terminating resistors on your i2s lines?

they are 50ohms, 75ohms is for external use, nobody uses 75ohms for i2s or even spdif internally. there are already a number of boards using ufl connectors, nothing so far that uses ancient dacs though there is a partial design in this thread for a TDA1541A that has them optional to use with fifo, but development seemed to stall.

termination will depend on the board (thickness and trace-width ie characteristic impedance), some will have it at the sending end, some will have at the receive end, its rarely 50ohms though, normally 22-33ohms is used.

Tazzz, its not documented anywhere, but its there on the board, how else does it select its own clock? the designer has put quite a few extra functions in the firmware editor, i'd say with a bit of ingenuity the clock select signal could be tapped or even sent on the DSDOE pin. ask the designer, I have no need for it so no help from me i'm afraid. he has been forthcoming with some changes and there is definitely undocumented features and control, but no hand holding =)

s3tup, I believe you are on the right track =) remember its also available as a chipset for OEM, there has to be backdoors or even front doors to access this stuff, you may not even need to rewrite anything

[erin]

Originally Posted by qusp

termination will depend on the board (thickness and trace-width ie characteristic impedance), some will have it at the sending end, some will have at the receive end, its rarely 50ohms though, normally 22-33ohms is used.

Perhaps you would be kind enough to explain why a person would not use a 50 ohm resistor in this application? Is it to do with the short length of wire?

[qusp]

because there are other elements that contribute to the series impedance, some do use 50ohms but its pretty rare these days and as I mention in the part you quoted, its not hard and fast, different flip flops, logic, different PCB thickness, different trace thickness (both of which define the line impedance), different impedance that may already be at the sending end, the speed of the connection, rise time etc. its on a case by case basis, but 50 ohms is less likely.