Thread: Rotel RVC240
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Old 16th Sep 2020, 1:24 pm   #9
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 4,999
Default Re: Rotel RVC240

For evidence, you just have to look again at how the Delta tune works.

To shift the crystal downwards, a larger than usual capacitance (47pF) is switched in in parallel with CT2

With the crystal on-frequency, there is a smaller capacitor (18pF) in parallel with CT2. This is probably the value that the missing C3 would normally have in a set without the Delta Tune feature.

To shift the crystal high, both the 47pF and 18pF capacitors are switched out, leaving only CT2 down to GND.

Therefore more capacitance = greater downward shift.
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