Re: uBitx V5 Audio improvement

Jim Tibbits
 

Attached couple of mods I've been using ...One variable audio filter and one mod Re 386 ...
The 386 shows what I measured on the ic with a 10 uF cap pin 1-8 ...flat from near dc to daylight ..What I heard was LOTS of wideband noise ..Cut it with the installed L/C filter ... then installed the op-amp variable filter ..found I did not need the 386 bandpass mod with the variable filter ...both mounted on same board and plugged into U1 socket on V3 board ...dono what would be needed to adapt to ver 4/5

Jim
LM386 Bandpass Filter.jpeg


On Tue, Apr 9, 2019 at 9:26 PM Ashhar Farhan <farhanbox@...> wrote:
Exact!

On Tue 9 Apr, 2019, 12:09 PM Jerry Gaffke via Groups.Io, <jgaffke=yahoo.com@groups.io> wrote:
For LM386 gain that is flat across 300 to 2300 Hz 
and is more than 26dB (no cap) but less than 46dB (10uF cap),
this is done by adding a resistor in series with that 10uF cap.

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