need advice of TDA1545A DAC

[ishiru]

i see..if i go further 1.6v limit, what's the worst case?..the Vout dropped or distortion or maybe the chips going kaput?

oh great.did you post that in your blog?.i might give a try

 

[abraxalito]

Going over 1.6V can fry the chip. At least I have blown one chip up by doing this, can't recall if it was a 1545 or a 1387 though.

Haven't shown a complete schematic for the LAID DAC just outlined how it goes on the blog. I also built a DAC with 19 chips doing 2X oversampling without any digital filter two summers ago

 

[ishiru]

oversampling without filter?.how come?
what's your opinion between NOS and 2x OS?

 

[abraxalito]

You'd have to read my blog on the 'LAID' architecture to find out the details. I was using an analog FIR filter to do it.

In the end I abandoned that as NOS with a passive filter sounded better. NOS is better sounding I think because there are fewer glitches in the output. Passive filtering reduces the audio band glitching even further.

 

[ishiru]

so..it means my ears didnt goes wrong when i compared OS w/ NOS one

i'll take a look of your LAID
interesting!

 

[abraxalito]

Seems all of our ears aren't lying. General consensus is that any amount of OS reduces dynamics, OS sounds 'greyer' in tonality.

 

[ishiru]

i measured the VRef on pin 7..they're 3V for real!.idk how they could survive

or i should remove the I/V first to measure?

 

[abraxalito]

How can it be 3V and still get sound? Interesting - what are the components connected to pin7?

No, no need to change the circuit to make this measurement.

 

[ishiru]

just like the datasheet said 22kOhm Takman REX from Vdd, then connect it to 2x33kOhm (parallel, which makes it about 16.5kOhm) Roederstein Mk4 in series..470nF vishay between the 1st and 2nd resistor

 

[abraxalito]

You're sure you measured the voltage between pin4 and pin7? Can't see how 3V is possible with those component values.

 

[ishiru]

4 is ground, then, yes..it's 3v

but i'll try to use analog meters tomorrow..i'm afraid it just my cheapo DMM being dumb

 

[ishiru]

hi..

today, i tried to lower the VRef voltage to 1.6v

but the result was disappointing .the sound gets more warm characteristics but it's distorted and i should turn on and off my DAC several times to got the sound comes out (maybe the chips couldn't get the callibration?..or just my phone's USB out being dumb?)

i also got some shock after touched 430V supply and sudden sound (the chips was loosen after i modded my USB-spdif output which results the sound was distorted so much .when i touched the chips the sound went freakin loud )

spdif coupling caps also play role here
i changed my wima mpk10 0.1uF from my x-fi digital out to a 10pf ceramic and now it sounds more warm yet the high sounds better
i have no idea why the digital coupling caps can sounds different