Hello to all,
a crazy idea.
Say I would want to implement a volume control at the I/V resistor level by replacing the current 1.3K resistor with a 24 step rotary switch. (I assume the TDA1543 would be fine with lower resistor values which would reduce voltage swing ).
What type/brand would you suggest ? Any other suggestions ?
a crazy idea.
Say I would want to implement a volume control at the I/V resistor level by replacing the current 1.3K resistor with a 24 step rotary switch. (I assume the TDA1543 would be fine with lower resistor values which would reduce voltage swing ).
What type/brand would you suggest ? Any other suggestions ?
Yes the resistor would go to ground...
"there are both minimum and maximum values"... You are referring to the compliance voltage ?
I would remain within this voltage even if I lower the IV resistor...
I did actualy read the datasheet, so maybe there's something I'm not getting right..
The best and cheapest alternative to special resistors at the I dac output (with certain sound degradation, audible no matter how special your resistor is) is to first send that I to a transistor, you then place any I/V resistor controlled with the transistor which are not sensitive to it. Then a final stage, some feedback and voilà.
If you have a resistor connecting the TDA1543's output (pin 4) to ground to provide a passive I/V circuit, there's a DC voltage on pin 4.
If you already have a DC blocking capacitor in the circuit, your volume control needs to go between that capacitor and the pre-amp or power amp the DAC is driving.
I've had excellent results controlling the levels from both TDA1541- and TDA1543-based DACs using a stepped attenuator (IOW, your basic idea is sound) but the DC voltages must be blocked.
OTOH, if I've misunderstood your circuit, can you explain it more fully?
HTH
D
Hello, thanks for your reply. I made some wrong assumptions and it cannot be done the way I was thinking. Will consider the attenuator after the capacitor as per your suggestion.
Ahaa that is probably what I am already doing because the DAC's output feeds into a BC327. What I did not know is that in this case resistor quality is less important (or unimportant
)What I did not know is that in this case resistor quality is less important (or unimportant
Ah, but a passive I/V stage has its own advantages. If you haven't read it already, visit DDDAC 2000 for more on this. (Much of it is no longer relevant but it's still worth a look.)
D
Yes I was aware of Mr DDD thanks
This is the active setup I am working with (but still has a resistor to ground..
)https://www.diyaudio.com/forums/dig...elp-noob-building-9028-dac-2.html#post5256178
Ahaa that is probably what I am already doing because the DAC's output feeds into a BC327. What I did not know is that in this case resistor quality is less important (or unimportant
Yessssss! unimportant
I built 3 boards for my first diy dac tda1541.
El cheap o metal film 1 cent each
Flame proof from India 3 cent each
PRP 1$ each
I did the same thing with 2 Pre-amp boards PRP vs India cheapo, 0 feedback design
In both cases the Flame proof coated from India had the best sound.
The el chopo metal film didn't sound good.
The PRP sounded good but I preferred clearly the sound of the Flame Coated
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