Distortion when more than 1 voice

[cdswift]

Hello,
I've just finished building a new PreenFM2.  I notice that when I play a patch with a single note  - sound is clear but when I play a second note (or more), the clear sounding patch turns noisy - just like clipping distortion.  Any suggestions?

Also, I have extremely good high frequency hearing and will use Preen with headphones.  I do not think any of the OLED fixes will make the whine go away so I am considering 'downgrading' to a 2004 LCD and modify the case to fit.  Are there any downsides to going to LCD (other than aesthetics) ?

Many thanks
Chris

[solipsvs]

lower mix levels and/or filter gain

[cdswift]

Suggestion about mix levels is a good one but, strangely I do not seem to be able to repeat this problem and all patches now seem very clear to me.

Also, I re-housed my Preen in the official case & made an OLED screen out of 2 pieces of perfboard back to back (copper sides together) and sandwiched a couple of sheets of goild between them.  Then I just taped the 2 pieces together, insulating the edges.  The benefit of this EMF screen is that there is no risk of short circuits from OLED or board components penetrating through a polythene bag.  Anyhow, very happy now - cannot hear the whine any more.

[SMF]

Also, I re-housed my Preen in the official case & made an OLED screen out of 2 pieces of perfboard back to back (copper sides together)...

As I have already written in the LCD-Whine-Thread:

My tests clearly show, that this is magnetic coupling from the inductor (used in the OLEDs PSU) of the OLED-Board. So a by far better solution than aluminium-foil, copper-plated PCB back-to-back, whatever (really Gold?), is to use a ferro-magnetic and electrically conductive material such as iron. Just go to the super-market with a magnet and buy some soda-cans made out of tin and not of aluminium. Empty them, cut out fitting sheets, sand the sheets, so there is no lacquer left on it (so it's conductive all over!) and place that in-between your perfboards... (use at least one -- better more -- ground-wires)

best,
Stefan

Edith says: "tin" soda-can can be misleading. What's meant is: soda-cans made of tinplate (tin plated steel). Can be easily identified with a magnet...