|18th March 2020, 02:43 PM||#501|
Join Date: Aug 2008
Perhaps lifting the shield grounds from the case on the input side, but keeping them connected is correct? I'll make a drawing.
Last edited by BigE; 18th March 2020 at 02:50 PM.
|21st March 2020, 03:24 AM||#502|
Join Date: Aug 2008
KOR952 WROTE below( I've tried it never better....., it's great for my Benz wood HO )
If there is more gain needed (+ 15dB), for instance when a Denon DL-103 is used, it is possible to change the second stage as follows.
R2 = R3 = 1k8
R4 = R6 = 1M
R5 = 100k
C2 = 3.3nF
C3 maybe the same (10uF) but may be changed to a 4.7uF
The gain of the first stage is R1 / cart. imp. x loss factor (due to the parallel RIAA cap)
For a DL-103 this will be 1620 / 40 x 0.9 = 36.45 x
The gain of the second stage is R5 / R3
For the original this will be 33k / 3.3k = 10 x
For the modified 15dB + version this will be 100k / 1.8k = 55.55 x
Output of a DL-103 with the original components = 0.3mV x 36.45 x 10 = 109 mV
Output of a DL-103 with changed components = 0.3mV x 36.45 x 55.55 = 607 mV
Difference in output is 14.9 dB
If you want less gain change R2 and R3 to a higher value, for instance 2.2k instead of 1.8k gives -1.74dB (0.818x) less gain.
RIAA filtering will not change while the values of caps and resistors are switched.
My 2 cents,
Last edited by BigE; 21st March 2020 at 03:27 AM.
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