turntable subsonic filter

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#2
jkojic said:
i was looking t put one between turntable and amp (integrated)-is this possible-
know one even mentions the idea in forums
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You could build an op amp high pass circuit. I'd first check if your arm and cartridge are compatible,
so their LF resonance is around 10Hz, and also if the turntable is well isolated from feedback and vibrations.

IF that is all ok, maybe your amplifier's existing filter could be altered to serve as a simple subsonic filter
instead of having to build an external one (which could go in the tape loop).Project 99 - Subsonic Filter
 
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#3
If you are connecting the turntable to the phono input of the integrated amplifier, you can not connect a subsonic filter between them.
The only way is to connect the turntable to a phono preamp, then a subsonic filter and then to the auxiliary input of the integrated amplifier.
There is an exception. If your turntable already has a built-in phono preamp. You can insert a subsonic filter and connect to the auxiliary input.
 
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#5
There is a wonderfully complex Elliptical HPF that Doug Self designed in linear audio that gives some seriously good performance. However, the damage has still been done to you signal so you are generally better off damping the tonearm.

There is also this The Signal Transfer Company: The Devinyliser for which PCBs are available and there is a thread on here with some signal/noise ratio 🙂. I post this because it helps to think about what is going on at LF with vinyl just to see if there is a better way!
 
#6
rayma said:
You could build an op amp high pass circuit. I'd first check if your arm and cartridge are compatible,
so their LF resonance is around 10Hz, and also if the turntable is well isolated from feedback and vibrations.

IF that is all ok, maybe your amplifier's existing filter could be altered to serve as a simple subsonic filter
instead of having to build an external one (which could go in the tape loop).Project 99 - Subsonic Filter
Click to expand...
hi thanks i like the alter idea- i have dynaco sca-35 - it has a high filter for scratchy vinyl- never use it- is low pass the term- ill need high pass?
 
#7
jkojic said:
hi thanks i like the alter idea- i have dynaco sca-35 - it has a high filter
for scratchy vinyl- never use it- is low pass the term- ill need high pass?
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Yes, you can adapt that filter switch for a rumble (high pass) filter, of 6dB slope.
It is already a bass cut filter set at 63Hz, by capacitors C11 and C12.

For a bass cut at 30Hz instead, double their values from 10nF to around 20nF.
For 20Hz instead, triple their values, from 10nF to around 30nF.

At the same time, remove capacitors C13 and C14, which form a treble filter
that you won't want.
 
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#12
jkojic said:
what type of capacitor is it-voltage says 400v-seems a lot ? i can snip
off c13 and c14 i can see the effect at 63hz?
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Yes, you could use 200V or 250V capacitors instead,
since they are after the coupling (DC blocking) capacitor.
If possible use polypropylene types.

Cut off C13 and C14 to eliminate the HF (scratch) filter.
This will leave only the 63Hz filter working.
 
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