"Reference" TDA1541A DAC with I2S-BUS architecture

[ernesternest]

DD's USB2I2S

Having one or two TDA1541As to hand, I bought some of Oliver's PCBs with a view to finishing off projects that had, well, taken a lengthy break . . .

I've just finished the first which uses a "crownless" 1541A chip and PSUs based on LM317s and 7805s in a Cascode arrangement (not the usual double regulator bodge) that I bought in kit form about ten years ago but never used. Input is via one of DD's USB to I2S modules and the I/V stage uses a couple of Sowter 8347 transformers that did duty for years in an upgraded CD player. Though it cost only buttons, it sounds rather good.

However, to get it to work I had to remove pull-up and pull-down resistors R28 and R31 in the BCK line. Until I did that, no sound at all.

Has anyone else tried DD's module in this application? If so, did you have the same trouble or have I done something wrong?

OTOH, if anyone does try the module and gets no sound, this might be worth a try.

Dave

Hi Dave,

I am facing this issue as well! Tried it later with DD's SPDIF input board, and it worked. Thats why I thought I had killed the USB board doing some earlier mods. So this would be good news if I was wrong. I'll give it a try later. Thanks for posting this.

Regards Ernst

 

[Malka07]

Hi Dave and Ernst,

Im not sure if your aware of this thread here...
http://www.diyaudio.com/forums/digi...04-transceiver-module-tda1541a-problem-2.html

But i use a Twisted Pair Spdif tranceiver and have the no sound or distorted sound problem...another member who uses the Y1 USB-to-I²S converter is having the same problem...Oliver has found that both these board lack the BUS Buffer (74HC125) between the converter IC and the I2S output...that his Teralink x2 has and which works with the dac.

Maybe the DD Board also lacks this? If this indeed is the problem??

Alon

 

[Ryelands]

Maybe the DD Board also lacks this?

Thanks for that - I forget where I read what that gave me the idea of removing the resistors - on this forum somewhere but not there. Whatever, I'm running now.

DD's USB-to-I2S module uses the PCM2707 which drives the I2B bus directly. I've been happily using one to drive three 12-way TDA1543 "towers" for a couple of years so to say it "lacks" the buffer might not be quite correct: it doesn't need a buffer. OTOH, it's limited to 48HKz.

If the same mod gets Ernst's board going, it would seem we're getting somewhere. Watch this space . . .

Dave

 

[ernesternest]

Buffer

The buffer in Doedes case was/is located on the DD TDA1543x12 board. Somewhere in my chaos it must be around. I already pulled all usable items but not the buffer. I'll try this, but will take some time after I decided to modify the ECDesign I/V to MK5. DDs SPDIF input board is working without the buffer inbetween. Seems that the PCM2707 I2S output voltage swing is too small for further attenuating....
Yes just had a look, the 74VHC125N is on the towerboard. I'll separate this part of the board and use it for this new purpose. Good to know.

Cheers Ernst

 

[studiostevus]

I have the separate DD SPDIF board (no optional USB board) and it does include the 74VHC4040M. Strange that this is a different setup than the integrated converted board

 

[ernesternest]

This is Doedes normal setup. On the SPDIF inputboard there is this 7404 bug. This is used for reclocking, if I am not wrong.

Ernst

 

[dvb projekt]

So, we can call this DAC a new type, I think:

SOS - Slightly Over Sampling. He he

Hi Lucas,

a bit OT but for us as Mac users, did you know and tried THIS nice software?

 

[dvb projekt]

Lucas,

install the software and use the following settings:

1st set the X2 in the Audio-Midi-Setup to 96 Khz / 16Bit

- activate "Memory Play"
- activate the upsampler

Now the songs from iTunes were:

1st load into the RAM (no disturbances from the HD)
2nd upsampled to 96KHZ (max. possible for the X2)

And the sound.... UNBELIEVABLE You must try it yourself.
I guess you would hear your complete library again over the weekend
I purchase the SW definitely before the trial is running out!

 

[toufu]

Which SPDIF solution is the most space efficient? I don't have much space left in my chassis. Thanks.

 

[LucasAdamson]

Lucas,

install the software and use the following settings:

1st set the X2 in the Audio-Midi-Setup to 96 Khz / 16Bit

- activate "Memory Play"
- activate the upsampler

Now the songs from iTunes were:

1st load into the RAM (no disturbances from the HD)
2nd upsampled to 96KHZ (max. possible for the X2)

And the sound.... UNBELIEVABLE You must try it yourself.
I guess you would hear your complete library again over the weekend
I purchase the SW definitely before the trial is running out!

I can't afford it but I will try it out sometime. Thanks for the suggestion Oliver.

 

[LucasAdamson]

Just reread your post Lucas, and noticed that you removed the TL431s...did you notice a difference in SQ?

It's pretty much impossible for me to say, because I don't think the unit could be said to have burned in by the time I removed them. I can say, however, that I have an adjustable voltage now, not determined by the TL431 regulators which are often inaccurate. In my opinion, it is quite unnecessary to have them there. Usually simplification is best in hi-fi I've found, unless there are good scientific grounds to complicate, and in this case there are none that I have heard. The TL431s are in this circuit secondary shunt regulators, quite inferior to the discrete Salas regs and of much higher impedance. The idea behind installing them, I believe, is to avoid intermodulation, which can happen when two loads share a common power source, and a spike of demand on one load then affects supply to the other. This is moot in the case of this design, as both loads are identical devices pulling identical loads for any given millisecond. Salas, the chief moderator of this forum agrees with this, which is good enough for me. He did say, however, to get the Salas shunts as close to the chips as possible and use the best conductors you can to supply them, which to me meant cutting the boards in half, trimming the traces as appropriate, scraping the ends of the traces and soldering .6mm pure silver wires onto them to run the supplies as close as possible. It is not as neat, for sure, but is easy to do and worthwhile I thought.

 

[LucasAdamson]

Has anybody got the Twisted Pear SPDIF to i2S board working yet?

 

[Malka07]

Has anybody got the Twisted Pear SPDIF to i2S board working yet?

Hi Lucas,

I have got the Twisted Pair Spdif to 12s working but with distorted sound...it appears that Oliver may have found the problem.

I´ve looked deeper on the three modules (TP WM8804, Y1 PCM2707 & X2 TE7022).
All three IC´s runs with 3.3V, so that´s not the difference.

The X2 is the only one, witch have a BUS Buffer (74HC125) between the converter IC and the I2S output.

On the Twisted Pear and the AMB Y1 pcb lacks this buffer.

I will try to insert such a buffer IC between the output of my TP WM8804 and the I2S input of the DAC module in the next days and report the result.

So just waiting to see if Oliver gets it working, when he has a spare bit of time.

BTW thanks for letting me know about the tl431's...when i get the dac working...i will let it burn in with the tl431's and get used to the sound, then i will try removing them as you did and report if i hear a difference.

Alon

 

[dvb projekt]

So just waiting to see if Oliver gets it working, when he has a spare bit of time.

I just waiting to the 74HC125 from Mouser. They should arrive before the weekend.

I will try to make a small adapter pcb to get it between the TP and the DAC module.

 

[Malka07]

I just waiting to the 74HC125 from Mouser. They should arrive before the weekend.

I will try to make a small adapter pcb to get it between the TP and the DAC module.

Thanks Oliver

 

[studiostevus]

Ernst, you mentioned you have a CCS loaded anode follower for another one of your dac's. I am planning to build one as well, would you happen to have the schematic of the implementation you use (or some info on which tube, feedback yes/no, etc) ?

Btw, did you have any chance to try out ecdesigns mk4 output stage? I have the full kit complete now, only no output stage, so no sound :-(

Thanks!

 

[Ryelands]

USB-Isolator

Oliver wrote:

Better dynamics, enhancement of the low end, better 3D soundstage and a deeeep black background. From my side: Highly recommended

Well, I'm glad you like it! (And a bit relieved, to be honest.) Could you possibly answer a couple of questions about it?

1. Regardless of what speeds you normally use (i.e. 44.1KHz), can it pass data to the Teralink at higher rates (i.e. 96KHz)? In theory, you should but, when I tried it, I couldn't. However, I was using an E-MU 0202 and that behaves oddly at times.

2. I bought the pre-assembled version of the board. When you bought yours, did it come with the chip already soldered or did you fit it yourself? (Not sure I'm up to soldering SM devices these days . . . )

Thanks

Dave

 

[dvb projekt]

Hi Dave,

to your questions:

1. Regardless of what speeds you normally use (i.e. 44.1KHz), can it pass data to the Teralink at higher rates (i.e. 96KHz)?
In theory, you should but, when I tried it, I couldn't. However, I was using an E-MU 0202 and that behaves oddly at times

Because of my iMac i could use the Pure Music software, witch is able to upsample all input files up to 192KHz/24bit.
Also the 96KHz setting for the X2 is possible and works awesome. I use it in 16bit modus for my TDA1541A DAC.

2. I bought the pre-assembled version of the board. When you bought yours, did it come with the chip already soldered or did you fit it yourself?
(Not sure I'm up to soldering SM devices these days . . . )

I solder all chips by myself. If you have the right solder iron, it´s no problem.

BTW, for all who use also the Teralink X2 and are interested, i made a clock upgrade to the HighEnd Tentlabs XO HERE.

Best regards,
Oliver

 

[ernesternest]

Ernst, you mentioned you have a CCS loaded anode follower for another one of your dac's. I am planning to build one as well, would you happen to have the schematic of the implementation you use (or some info on which tube, feedback yes/no, etc) ?

Btw, did you have any chance to try out ecdesigns mk4 output stage? I have the full kit complete now, only no output stage, so no sound :-(

Thanks!

Hi,

I used the design which "Adamus" posted somewhere in the middle of the OLD DACEND2 thread. It is rather simple with 2 fets and 2 resistors, like K&K Audio. Don't remember the Fet type and have not option during the next days to look after. Please search on your own.

I just reduced B+ from 270V to 170 and replaced anode resistor by the CCS, which I set to 15mA. So far my tubes are E182CC and 5687. E182CC in my case is better, smoother with better heights. I January I'm trying 6n6p in the same configuration. For now I admit, sound without CCS is somehow better in the mids and heights, but bass is slightly weaker. So I'll put the resistors back in place.

Ernst

 

[dvb projekt]

Got it working!

With the missing 74HC125 between the Twisted Pear Opus WM8804 and the DAC modules, it runs like hell.

An externally hosted image should be here but it was not working when we last tested it.

The configuration is as followed

Pin1: to GND
Pin2: Input 1
Pin3: Output 1
Pin4: to GND
Pin5: Input 2
Pin6: Output 2
Pin7: GND
Pin8: Output 3
Pin9: Input 3
Pin10: to GND
Pin11: N.C.
Pin12: N.C.
Pin13: N.C.
Pin14: Vcc (+5V)


Perhaps someone have a nice small DIP14 pcb witch looks better than mine.

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