TDA1541A/S1 Arrangements

[rah]

Hi all,

Recently we’ve become interested in building a DAC, and after spending a lot of time looking into design issues. We’ve decided to give non-oversampling DACs a go (As a cheap start into a never-ending process).

Being engineering students, the theory has never been a problem for us, but the lack of funds/time a student has means that we rarely get to do subjective development. If you could help us out with your experience with the TDA1541A, and get us started, it would be great.

Two questions for the TDA1541A fans:


Question 1
-----------

We know that some of you have tried many arrangements of using TWO TDA1541A DACs, including:

1) Parallel TDA1541As
2) Balanced TDA1541As with R+ and L+ on one, and R- and L- on the other.
3) Balanced TDA1541As with R+ and R- on one, and L+ and L- on the other.

In your opinion, and listening tests, which gives the best sound subjectively?


Question 2
------------

Can any arrangement of TWO TDA1541As equal a single TDA1541A S1 in sound?
Or will the single TDA1541A S1 always outperform two TDA1541As using the best arrangements for each ?

Basically we have a choice, we can either obtain a single TDA1541A S1 or two TDA1541A. We want to take the one from which we can obtain best sound (Applying all tweaks, arrangements, etc...). But the TDA1541A S1 is 3 times the price of 2 x TDA1541A.

[till]

did you build a balanced TDA1541 DAC? Do you have any drawing of you circuit?

[rah]

Unfortunately not, I never got the time, and those DACs are still sitting where I put them

If you're interested, take a look at:

TDA_1541A input formats

I've posted some info here, but you'll have to work out a few things.

I'll post what I did, when I get around to doing it, hopefully soon...
(But plz don't wait)

[till]

I´ll wait. I have some TDA1541A (and some AD1865 etc) laying around for some time, because of the plan to build a balanced DAC ... but same as you describe.

The thread above i know, but i fell not skilled enough to work thing out. I´ll wait until someone posts a simple and working circuit for feeding the DAC right way for balanced operation.

[guido]

Originally posted by till
I´ll wait. I have some TDA1541A (and some AD1865 etc) laying around for some time, because of the plan to build a balanced DAC ... but same as you describe.

The thread above i know, but i fell not skilled enough to work thing out. I´ll wait until someone posts a simple and working circuit for feeding the DAC right way for balanced operation.

Simple: one dac for L+ and R+ connected in the normal way.
other dac for L- and R- by inverting the dataline.

one dac for L+/L- and one for R+/R- here:

2 Tda1541a

I'm still looking at the output options, so no comment on 'sound' yet (i know it is taking loads of time with this thing...).

Regards,

[till]

i did see that thread also, i can´t make GALs, and i think the circuit has not really few parts. Lots of ICs. I had the hope for something more simple to build. What about DACs with parallel input? Or one programmable chip doing all the work for digital inverting.

[guido]

Originally posted by till
i did see that thread also, i can´t make GALs, and i think the circuit has not really few parts. Lots of ICs. I had the hope for something more simple to build. What about DACs with parallel input? Or one programmable chip doing all the work for digital inverting.

Indeed lots of parts. But you can buy the pcb, so if you really want to get the TDA's working like this it is just a matter of buying pcb and the components. And yes, you need to find somebody to program the GAL (there is one obvious person to ask, i guess .... )

You could program the whole lot into one modern CPLD, but then you need to find somebody to do this with a programmer.

For DACs with parallel input, you need logic to convert I2S into parallel datastream = more parts. Early BB are parallel: PCM53, 54 and 55, but they are mono: you need four of them

If you want differential but with not so many parts: use the DACs in stereo and just invert the dataline to one of them.

The GAL has advantages: looking at the cambridge cd3 way of getting to 16Fs, i had a look if i could get 2Fs. It is possible with some reprogramming of the GAL (output DAC1: left sample & previous left sample, DAC2 right sample and previous right sample).

I sacrifised mute to switch into this mode (muting done with 7210). If it gets me anywhere, i dont know. But just to show that progr. logic has it's advantages.

Just to show off :


DAC
GUIDO BALTUS

CHIP GAL GAL20V8

LATCH GO WSDELAY SHIFT64 SHIFT32 DATA WS DIFFERENTIAL ONEFS CLKDIV2 CLKDIV4 GND
/OE NU1 DATAL WSL I2SCLK WSR DATAR FIFOREAD CLOCK CLOCK_INV NU2 VCC

EQUATIONS

FIFOREAD = /GO + GO * /CLKDIV2 * CLKDIV4 +
GO * CLKDIV2 * /CLKDIV4

CLOCK = CLKDIV4
CLOCK_INV = /CLKDIV4

I2SCLK = /CLKDIV4


WSL := ONEFS * /WS + /ONEFS * WS

WSR := ONEFS * /WS + /ONEFS * WS

DATAR := ONEFS * WS * DATA +
ONEFS * /WS * SHIFT32 * DIFFERENTIAL +
ONEFS * /WS * SHIFT32 * /DIFFERENTIAL * WSDELAY +
ONEFS * /WS * /SHIFT32 * /DIFFERENTIAL * /WSDELAY +
/ONEFS * /WS * SHIFT32 +
/ONEFS * WS * DATA


DATAL := ONEFS * WS * SHIFT32 +
ONEFS * /WS * SHIFT64 * DIFFERENTIAL +
ONEFS * /WS * SHIFT64 * /DIFFERENTIAL * WSDELAY +
ONEFS * /WS * /SHIFT64 * /DIFFERENTIAL * /WSDELAY +
/ONEFS * /WS * SHIFT64 +
/ONEFS * WS * SHIFT32

[till]

you can buy the pcb,

in case some people descide to do, i´m in. Alone i fear that i´m not skilled enough to solve the problems until it works.

If you want differential but with not so many parts: use the DACs in stereo and just invert the dataline to one of them.

simply connect one normal, and one with an inverter in sdata line? thats all?

this http://www.diyaudio.com/forums/showt...953#post300953 looks more difficult

whats the drawback of this solution? does it also work with other DACs?


Another point: could you please give me a link to a TDA1541 datasheet? i can´t find it.

[rfbrw]

Originally posted by till
this http://www.diyaudio.com/forums/showt...953#post300953 looks more difficult
whats the drawback of this solution?

None that I can see but I do not know what you consider a drawback.

does it also work with other DACs?

No. It is strictly for the TDA1541/A and and it must be balanced.

Another point: could you please give me a link to a TDA1541 datasheet? i can´t find it.

Go to Google and click on advanced search. Set the search to return pdf files only and search for the TDA1541 or TDA1541A.

ray.

[Andypairo]

Originally posted by till
i did see that thread also, i can´t make GALs, and i think the circuit has not really few parts. Lots of ICs. I had the hope for something more simple to build. What about DACs with parallel input? Or one programmable chip doing all the work for digital inverting.

I can easily program GALs at work, just in case... (not sure but probably have the right GALs/PALs too)

Guido, is this the JEDEC file or do you provide one on request?

Cheers

Andrea