Hello. Can anyone help with how to modify the input sensitivity of a Linn LK85 so that it works better directly connecting to a Chromecast Audio?
The LK85 has an input sensitivity of 685mV whereas the Chromecast output is 2V. There is a LK85 schematic here, could it be as simple as changing R106/R107?
The LK85 has an input sensitivity of 685mV whereas the Chromecast output is 2V. There is a LK85 schematic here, could it be as simple as changing R106/R107?
R107 is for stability and has no effect on sensitivity.
R106 defines the DC input resistance and also biases the power amp chip.
To reduce the sensitivity you need to add a resistor in series with signal path to work in conjunction with R106. If the audio comes in at 'P1' then add a series resistor there (which would mean cutting the print and adding the resistor across the gap. So that is somewhere between P1 and the Drain of the FET
R106 defines the DC input resistance and also biases the power amp chip.
To reduce the sensitivity you need to add a resistor in series with signal path to work in conjunction with R106. If the audio comes in at 'P1' then add a series resistor there (which would mean cutting the print and adding the resistor across the gap. So that is somewhere between P1 and the Drain of the FET
Trial and error to the subjective result you want. A 10k in conjunction with the 10k fitted would halve the signal level and is just a fixed version of a volume control.
In the diagram here, Z1 is the resistor you add and alter.
https://en.wikipedia.org/wiki/Voltage_divider
In the diagram here, Z1 is the resistor you add and alter.
https://en.wikipedia.org/wiki/Voltage_divider
In order to keep the noise low with the actual feedback resistor he could also go inverted at much less than half the gain in noniverted topology.Gains down to - 3x gain were reported as stable here:
https://www.diyaudio.com/community/...out-for-a-tda7293-composite-amp.368974/page-2
The sound might also improve in the inverted topology.
https://www.diyaudio.com/community/...out-for-a-tda7293-composite-amp.368974/page-2
The sound might also improve in the inverted topology.
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