Keys, Synths & Samplers

[SoundwaveLove]

Can anyone reccomend me a good oscilloscpoe program for tuning my future retro?  The scale is off and it's driving me CRAZY!

[RoadRanger]

http://www.sillanumsoft.org/prod01.htm

http://casa.accattatis.org:9090/Latest%20VA%20version/VA2012XE3beta0.3.exe

[mate_stubb]

I find your ear to be far more discriminating for setting scale than an oscilloscope or a tuner. I set scale by tuning a static oscillator to the same exact pitch, then play a couple of octaves away and adjust the scale, retune, and iterate.

Once it is fairly in tune across a couple of octaves, fine tune the scaling by moving to 4 or 5 octave intervals. You can tell by the beating (or lack thereof) when things are good. 

[SoundwaveLove]

I'm really having a lot of trouble with this.  It seems as soon as i adjust one octave to match the static note, the previous one gets off.  When I get a couple near eachother close, the third or fourth are way off, I can't seem to find any kind of balance and I don't know what to do.

[mate_stubb]

Which model are we talking about? Does it have 2 separate trimmers or 1? Some synths in the old days had a 1V/Oct trim that worked for midrange and low frequencies, and a separate high track to make it track better on the high end.

With those, you set the 1V/Oct first, then tweak the high track.

[SoundwaveLove]

It's the future retro xs.

There's a trim pot for "scale"  and one for "tuning"

It seems like an impossible balancing act with the scale pot.  There's no way to get it even across more than two octave, i end up just turning it back and fourth when i go up and down to lower octaves.

[SoundwaveLove]

I can't get it better than +-5 cents over the range of C1 - C6  Is this an acceptable margin of error for an oscillator? 

[mate_stubb]

Are these multi turn cermet type trimmers, or cheap carbon single turn ones?

Good:

Not good:

[SoundwaveLove]

Can't see inside.  The pots are tunable from the front panel, via tiny holes, but i can't actually see them.

5 cents seems like a lot, but can't get it better than that....

[mate_stubb]

Here's what I would expect from any modern synth advertising "ultra stable, wide range voltage-controlled oscillators, each capable of covering a range of 0.5 Hz to 100 kHz":

- I expect to be able to tune two oscillators to zero beating at a fairly high frequency, and hit a low note (say 5 or 6 octaves apart) to find none to very slow phasing or beating.

If your machine can't be trimmed to that level, some component may have shifted in value and you can no longer trim it to compensate.

Do you find that your trimmer is all the way to one side or the other when adjusted to best tuning?

[SoundwaveLove]

No it's not maxed out.  I think it's just a bit more work than i realized to get it right, going back and forth between the tune and scale pot.  I got it closer now, gonna keep on picking away at it.  Thanks for the help.

[mate_stubb]

Once you have done it a couple times, you'll get pretty good at it. As you said, make small adjustments then retune.

[XK-S -> 330…]

If you are using a small screwdriver, try holding it in place with the tip of one finger from your left hand (if right handed) on the end and turning the screwdriver with your right hand. It keeps the screwdriver stable and helps hold the screwdriver tip against the side of the slot in the direction pressure is applied.

[SoundwaveLove]

I got it to only drift only 2cents over 6 octaves.  That's close enough for me for now.

Thanks for the help!

[mate_stubb]

Good deal!