"Reference" TDA1541A DAC with I2S-BUS architecture

[dvb-projekt]

Originally Posted by neda

Thank you Oliver & Lucas for your help, I found the problem!
It was what we learned on our first day of electronics 101.
Make sure your GROUNDS are tight!!!
The input gnd to the converter was loose.

We're back in buisness, and sounding good, but still have a long way to go.

Best Regards,
Ned

Ahh ok So have much fun!

I am looking forward to your ready build DAC


Best regards,
Oliver

[wlowes]

Originally Posted by LucasAdamson

Lukas "Lampizator" Fikus has also staked his reputation on the fact that, when he set up an immediate A, B test to determine differences between output DC blocking, or "coupling" caps, he couldn't determine any single difference between any of them, including cheap electrolytic ones.

Go figure!

I must admit I was surprised by his findings. I found that using simple aligator clips to connect and reconnect caps realtively quickly made it fairly simple to check out the differences. I do suspect there is a lot of snake oil being sold at rediculous margin. I did on the other hand find differences in cap sound in this application even among the modestly priced units.

[dvb-projekt]

A short intermediate result to the TDA1541A DAC V3.0 module.

The 1st testings with the module are finished.
Everything works perfect and i could tell you,
that also the SQ benefit from the new design and modifications.

Now the 2nd test with -ecdesigns- MK7 Onboard Grounded-Gate MOSFET Current Buffer I/V Stage will start.

To be continued...

[dvb-projekt]

The Red Baron

aka TDA1541A DAC V3.0

The evolution brings the following changes

- Direct shunt voltage inputs with shortest onboard traces
- I2S In-/Outputs with shortest onboard traces
- Upgrades DEM Synchronizer
- Onboard Grounded-Gate MOSFET Current Buffer I/V Stage
(-ecdesigns- MK7 version)
- Compacter design


Still on the module

- Separate GND-Trace for DEM-Synchroinizer
- Master/Slave connectors for parallel DAC module usage
and external I/V Buffer stages e.g.
Tube-I-zator & DDNF Stage
- Groundplane
- no SMD Design





If you want to use the onboard Grounded-Gate MOSFET Current Buffer I/V Stage,
you need additionally the DC-Reference Module


Description

Because the Grounded-Gate Buffer is connected between the DAC output and the passive I/V resistor,
normally the I/V resistor is connected between the DAC output and GND,
you must get rid off the approx. 4V DC on each I/V resistor.
Therefore we must get a new reference GND for each channel.

The circuit is connected to the ref.+5V at the output of the buffer and GND,
with a decoupling cap for each channel.
By trimming each voltage so it exactly matches DC voltage on the I/V resistor,
the DC voltage between I/V resistor and reference becomes zero.
In other words, the DC component is removed without using a coupling cap.

[LucasAdamson]

Clever stuff!

I am only annoyed that I already have the old ones now - this looks so much better.

[dvb-projekt]

Here you see the two configurations.

1st without the onboard I/V buffer stage and in parallel mod





The shortest connection between the two modules
for the I2S signal and the analog output.



2nd with -ecdesigns- MK7 onboard I/V buffer stage








Because of a small failure in my pcb design program it is necessary,
that you switch the source and drain of the MOSFET like in this picture

[dvb-projekt]

Here are the setting points, if you use the onboard I/V stage.

All further informations in my Blog.

[studiostevus]

Soooo.... Sound?

[dvb-projekt]

Originally Posted by studiostevus

Soooo.... Sound?

Of the onboard I/V?

[studiostevus]

Yes