hi,
want resistors/values would i need to change for a lower roll-off (8hz) on k1803 mono pre-amp module pcb. The original spec for k1083 is 20Hz to 20kHz ± 3dB. i will be using this with my home cinema subwoofer.
kind regards
Without recalculating: you can replace all the capacitors of 10 uF with 22 uF-versions. That will help but why should you do that? Lowest sound ever recorded is 14 Hz and almost all audio engineers consider sounds below 20 Hz a waste of amplifier power.
[quote=“laserguy”]Without recalculating: you can replace all the capacitors of 10 uF with 22 uF-versions. That will help but why should you do that? Lowest sound ever recorded is 14 Hz and almost all audio engineers consider sounds below 20 Hz a waste of amplifier power.[/quote] thanks for the reply!!
what value capacitor is needed for 15hz?
regards
Next easy to get value above 10 uF is 22 uF. For 15 Hz it is possible (please experiment or simulate to be sure) to use a 15 uF capacitor but these are rare. In the past Philips sometimes used these.
ok what voltage 22uf capacitors will i need?
The same as Velleman uses will suffice.
Maybe it is a waste of power, but isn’t it so that these frequencies can be felt instead of hearing it?
One thing is for sure…at that low frequency…no need to go stereo.
Hi all,
I’ll be putting together 2x mono modules over this weekend - hope all goes well!! I know off some pre-amps that go as low as 8hz especially some studio type ones. Not particularly a waste off bandwith frequency power for my studio set-up as 
Also how would I go about reducing the output impedance as 40db is alittle to high (not using the pre for mic duties) for my needs. Could I change the resistor values to bring down the gain inside of changing different value pots. I would like the gain to be somewhere between 10 - 15db.
Kind regards
[quote=“Blocca187”]Could I change the resistor values to bring down the gain inside of changing different value pots. I would like the gain to be somewhere between 10 - 15db.
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You can see a trim potentiometer (RV1) of 220K/250K.
By trimming this you can set the gain between 0dB and max dB. Just put a little screwdriver in the middle of this component and turn it carefully.
greetings