TDA1543 and bass

If you're noticing good low-end grunt in comparison to regular DACs it could be those regular DACs have design flaws which are adding low-frequency noise.

TDA1543 sounds better, particularly at the lower end when an external current source is used and the internal one disabled.

In a NOS implementation TDA1543 normally does have rolled-off HF which subjectively can give the impression the bass is better.
 
Disabling internal CS is very easy - remove any connection to pin7.

External current source looks like the PNP (BC557) version of this schematic : http://www.talkingelectronics.com/projects/TheTransistorAmplifier/images/Fig71ba.gif

Omit the LEDs, the anode of the top LED is replaced by TDA1543 current output (pin6,8). You need to select the R value to suit your application (power supply voltage and I/V resistor).
 
Disabling internal CS is very easy - remove any connection to pin7.

External current source looks like the PNP (BC557) version of this schematic : http://www.talkingelectronics.com/projects/TheTransistorAmplifier/images/Fig71ba.gif

Omit the LEDs, the anode of the top LED is replaced by TDA1543 current output (pin6,8). You need to select the R value to suit your application (power supply voltage and I/V resistor).

Yes I see pin 7 is Vref with R to gnu...

In these example sch-s look like a current injection to the Iout?
Wht amount of current should be present from Power line to The Iout and What Riv are used?
Thanks :)
 
Yes - the external 2*PNP is injecting current into the Iout pin of the DAC. Inside the DAC there's a digitally controlled current source connected between Iout and GND.

Choice of current and I/V resistor is up to the designer. With TDA1543 you have considerably flexibility over the supply voltage (3-9V) - you decide what output voltage you need and select power voltage and I/V resistor to suit that.
 
Yes Thnks for the info.
Do You know maybe what value of inside current source is? And if it is some relation with Vref pin?
BRW
I build long time ago 16 x TDA1543 based machine. And main issue was temperature. I remember that I was employ huge heatsink to keep the temperature just slight warm at the 35deg outside one summer... It was straight forward design with common Rref and common Riv. Power was about 8V I think. The sound was (and still is very good, rich and natural with a very good LF end.