18-01-2015, 09:29 PM
Beautifully made David, there's something about wooden cases.
C1, C3 (22nF) and C2, C4 (220nF) look suspiciously like multilayer ceramic capacitors.
To achieve these values they will use a 'Hi K' dielectric (X7R or even Y5V) which has poor stability against temperature, time and applied voltage. See p 10-12 of http://www.johansondielectrics.com/image...007-12.pdf
The first two give rise to frequency drift and the third distortion.
Replacing them with film capacitors, which are much more stable and do not age, would be worthwhile.
Jim
C1, C3 (22nF) and C2, C4 (220nF) look suspiciously like multilayer ceramic capacitors.
To achieve these values they will use a 'Hi K' dielectric (X7R or even Y5V) which has poor stability against temperature, time and applied voltage. See p 10-12 of http://www.johansondielectrics.com/image...007-12.pdf
The first two give rise to frequency drift and the third distortion.
Replacing them with film capacitors, which are much more stable and do not age, would be worthwhile.
Jim
