There's something strange..
remove both 3.3 nf, then when i remove on only one channel, the 12 nf and i short it (with or without resistor), this channel is perfect (no riaa, right gain).
When I remove the other channel 12nf, on the channel previously ok (no riaa), come back the equalization and more gain.
In the second channel, the are no differences between with or without the 12nf cap
remove both 3.3 nf, then when i remove on only one channel, the 12 nf and i short it (with or without resistor), this channel is perfect (no riaa, right gain).
When I remove the other channel 12nf, on the channel previously ok (no riaa), come back the equalization and more gain.
In the second channel, the are no differences between with or without the 12nf cap
Do you want to convert this to a line amplifier with around 20dB of gain?
If so, one of the two RIAA capacitors in the channel would be removed (the smaller capacitor of the two),
and also the other RIAA capacitor in that channel (the larger capacitor of the two) would be shorted.
This would also short the largest RIAA resistor, so the gain would then be around 40dB and flat.
If you want only 20dB gain, install another resistor where the smaller capacitor was.
The value should be about 0.11 x the value of the RIAA resistor that is still in parallel with it.
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Thank you Rayma.
Yes I need to use it flat, without riaa equalization
The board have 1 other capacitor besides the smaller and the larger..
What do you think are to remove and to bridge?
Or maybe I have to do some tests..
Thank you again
i've numbered capacitors
Shared album - Dan Basta - Google Photos
Yes I need to use it flat, without riaa equalization
The board have 1 other capacitor besides the smaller and the larger..
What do you think are to remove and to bridge?
Or maybe I have to do some tests..
Thank you again
i've numbered capacitors
Shared album - Dan Basta - Google Photos
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Look for marked RIAA capacitor values of roughly 1000pF (sometimes marked 102)
and 3000pF (sometimes marked 302). The values could be somewhat smaller or larger for either, or both.
Ignore any other capacitors, as they have other functions. What flat signal gain do you want?
If you want a flat gain of 30dB, install an extra resistor in place of the smaller RIAA capacitor.
Value should be about 1/2 of the resistor that is in parallel with it (for 30dB gain).
Without this extra resistor installed, just the smaller capacitor removed, the gain will be ~40dB.
Also short out the larger RIAA capacitor in either case.
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I would not add the extra resistor first. If the gain seems too high,
only then add the extra resistor. Depends on your cartridge.
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