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DIY HiFi Forum Welcome! Need support, you got it. Or share your ideas and experiences. |
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DIY HiFi Forum Welcome! Need support, you got it. Or share your ideas and experiences. |
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In Reply to: Re: DIY DAC posted by mamu on January 10, 2005 at 08:10:52:
Hi,> could you please comment one the TDA1545 DAC from diyparadise.
In general fine, but Yeo made a hash with his "improvements" to the DAC Current scaling (BTW, I have always advocated to operate the TDA1545 at 2mA Full Scale Current, as far back as the late 90's).
As long as you operate the DAC with nominal Supply voltages you need to be very carefull how you arrange the passive I/V, in fact, the TDA1545 is non too well suited to passive I/V.
The DAC on +V supplies is strictly limited to a 3V Peak-Peak output Swing centered around a 3.5V Midpoint. In other words what you get out is 1V RMS.
If you bump up the current by connecting 11K from the 2/3 +V node (NEVER EVER use 1/2 +V) to 2mA Peak-Peak your I/V conversion resistor must be below 1K5, simply to not exceed the output voltage compliance and also be connected to 2/3 +V.
You can of course operate the DAC at overvoltage, in which case each Volt overvoltage increases the Output Range by 1V Peak-Peak, the midpoint is always at 2V + ((Vdd - 3V)/2).
But of course, if you go above 5V you live dangerously and on your own risk.
Other than this BIG caveat things should be peachy.
I probably would still recommend my Valve Output Stage to be used after the TDA1545, making sure to get 11K from 2/3 +V as reference and the adjust the nominal 375R cathode resistor untill the output voltage on the DAC is as close to 3.5V as possible.
Ciao T
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Follow Ups
- Re: DIY DAC - Thorsten 08:27:01 01/10/05 (3)
- Re: DIY DAC - mamu 10:43:16 01/10/05 (2)
- Re: DIY DAC - Thorsten 13:25:22 01/10/05 (1)
- Re: DIY DAC - mamu 22:37:27 01/10/05 (0)
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