Do NOT omit the bit disable switches! I labelled mine "Enable" instead
of disable. These optionally add the two more significant bits into the
three fixed outputs. What this means is that the fifth bit doubles the
range of the outputs and the sixth doubles it again. This is very
useful. As Ken pointed out, with 4 bits you have 16 semitones, 5 bits
32, and 6 bits 64. So it is not just the range, but the number of
possible discrete values on the output. You need those switches. You
will use them a lot.
I have the 4-pot mixer on the fourth output. I find that I don't use
this feature as much as the 3 fixed outputs, partly because I like the
fact that the fixed outputs are similarly weighted and I can use them to
drive serveral oscillators in a similar manner. On the mixed output I
have to dial up the weighting. This is very flexible, but also hard to
get right. If you want to save panel space, I'd suggest omitting the 4
mixing pots and hard wire the mix output to have some fixed weighting.
You could include all six bits in the 4th output if you did that.
I do not use output level pots, as shown on the schematic. I just put
100K resistors there to get the maximum output level. I took a lesson
from Bernie Hutchins (Electronotes) that attenuation is best done on
inputs. This also saves panel space.
-Richard Brewster
sasami@... wrote:
of disable. These optionally add the two more significant bits into the
three fixed outputs. What this means is that the fifth bit doubles the
range of the outputs and the sixth doubles it again. This is very
useful. As Ken pointed out, with 4 bits you have 16 semitones, 5 bits
32, and 6 bits 64. So it is not just the range, but the number of
possible discrete values on the output. You need those switches. You
will use them a lot.
I have the 4-pot mixer on the fourth output. I find that I don't use
this feature as much as the 3 fixed outputs, partly because I like the
fact that the fixed outputs are similarly weighted and I can use them to
drive serveral oscillators in a similar manner. On the mixed output I
have to dial up the weighting. This is very flexible, but also hard to
get right. If you want to save panel space, I'd suggest omitting the 4
mixing pots and hard wire the mix output to have some fixed weighting.
You could include all six bits in the 4th output if you did that.
I do not use output level pots, as shown on the schematic. I just put
100K resistors there to get the maximum output level. I took a lesson
from Bernie Hutchins (Electronotes) that attenuation is best done on
inputs. This also saves panel space.
-Richard Brewster
sasami@... wrote:
>>i'm unclear about the function & use of the "bit disable" switches on
>>outputs 4&5 of the infinite melody schematic...
>>
>>
>
>Bit Disable switches are to limit the range of the melody. with 4 bits
>running, you get a 16 semintone range. 5 bits, a 32 semintone range and 6
>bits a 64 semintone range out of the fixed outputs.
>
>
>
>
>>and then the associated mix ins. Are those ins optional?
>>
>>
>
>Those are for the 4th channel that is fed via pots instead of the fixed
>networks. You can wire as many or few of the bits to pots as you wish. If
>the switches are included, they will effect the bit 5 and 6 outputs to the
>pots. On the other hand, you can simply install only 4 pots (or 3 etc) on
>the lower bits.
>
>
>
>
>>and if you decide to omit them, should the disable switches be closed or
>>
>>
>open? >And and, what effects do they have on the final outputs?
>
>If you omit the mix ins totally (i.e., dont use any pots) simply don't wire
>them up. The bit 5 and 6 switches are still needed for the fixed networks.
>If you don't use the switches you will need to short out their positions if
>you want to permanently reduce the number of bits. Leave them open if you
>want the full range.
>
>I hope that's not too confusing!
>
>Ken
>_______________________________________________________________________
>Ken Stone sasami@...
>Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
>Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>
>
>
>
>