The output of the Monica2 DAC using a TDA1545 isn't quite like the application manual. It has a dc bias current on it and the circuit ties it to the REF through a resistor.
Being a current output DAC I assumed that it must be like the others which must have a low impedance load. The TDA1541 for example must not have more than +/- 25 mV at its output to stay within specs and so the load has to be much less than 50 ohms !
In the Monica the load is now a large resistance and it will have a significant voltage on it. Is this chip capable of working within spec with such a high load ? I'm thinking of terminating the output into a low impedance . Anyone tried that ?
Am I missing something here?
Cheers.
Being a current output DAC I assumed that it must be like the others which must have a low impedance load. The TDA1541 for example must not have more than +/- 25 mV at its output to stay within specs and so the load has to be much less than 50 ohms !
In the Monica the load is now a large resistance and it will have a significant voltage on it. Is this chip capable of working within spec with such a high load ? I'm thinking of terminating the output into a low impedance . Anyone tried that ?
Am I missing something here?
Cheers.
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I know by experience that the current sources of the TDA1543 can cope with quite hich voltage (better if using higher voltage supply), but with the 1545 I used Pass D1 stage.
Since Yeo seems to use it with good success I'd say "why not"... after all it is a 2 resistor experiment😉
Cheers
Andrea
Since Yeo seems to use it with good success I'd say "why not"... after all it is a 2 resistor experiment😉
Cheers
Andrea
Hi there,
I came across this thread when researching ways to improve the output stage of the Monica2.
My question is could I substitute some Lundahl LL1517's for the 2K2 output resistor. On the technical issues - is there a bias current into the outputs of the TDA1545. The LL1517 wants to be driven with an extremely low source impedance (minus 18R) and has a No load Impedance of 1K. This transformer could provide voltage step up of 1:2.
The question is will this work ?
Shoog
I came across this thread when researching ways to improve the output stage of the Monica2.
My question is could I substitute some Lundahl LL1517's for the 2K2 output resistor. On the technical issues - is there a bias current into the outputs of the TDA1545. The LL1517 wants to be driven with an extremely low source impedance (minus 18R) and has a No load Impedance of 1K. This transformer could provide voltage step up of 1:2.
The question is will this work ?
Shoog
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