Yes, in fact I made several mods. I should upload my schematics to show
all the changes, but I just moved to a new house and the computer with
my drawing program is still packed up along with my modular synth. I
changed the sawtooth output to be +/-5V, and drove the pulse wave
comparator from that with DC coupling, so the pulse wave always tracks
down to the lowest frequency. I added a bit of hysteresis to the pulse
comparator on the output. I made some changes to the frequency controls
inputs, too. I followed some ideas from the ASM VCO, which I recommend
you have a look at for reference. Ken's VCO board allows you to build
it in a lot of different configurations. I only built the VCO core and
didn't use the waveshapers because I wanted to have two VCOs in 1U MOTM
size panels.
As for the low frequency limit, the VCO core will go quite low with
negative VC inputs. But because the waveshapers are AC coupled, these
will have a low frequency limit in the low audio range, I would think.
-Richard Brewster
dustin sedlacek wrote:
all the changes, but I just moved to a new house and the computer with
my drawing program is still packed up along with my modular synth. I
changed the sawtooth output to be +/-5V, and drove the pulse wave
comparator from that with DC coupling, so the pulse wave always tracks
down to the lowest frequency. I added a bit of hysteresis to the pulse
comparator on the output. I made some changes to the frequency controls
inputs, too. I followed some ideas from the ASM VCO, which I recommend
you have a look at for reference. Ken's VCO board allows you to build
it in a lot of different configurations. I only built the VCO core and
didn't use the waveshapers because I wanted to have two VCOs in 1U MOTM
size panels.
As for the low frequency limit, the VCO core will go quite low with
negative VC inputs. But because the waveshapers are AC coupled, these
will have a low frequency limit in the low audio range, I would think.
-Richard Brewster
dustin sedlacek wrote:
>speaking of the VCO - anyone made any mods to it ?
>
>
>On Thu, 24 Mar 2005 14:20:52 -0000, charlesosthelder
><osthelder@...> wrote:
>
>
>>
>> Hi all!
>>
>> I've got two VCO pcb's on order and am getting the parts together
>> (yes, I'll get a US parts list together!)for an all-the-options setup.
>>
>> Can anyone tell me what the typical low frequency limit is without
>> mods? Also, do you have any useful build info that hasn't been
>> presented on the list?
>>
>> Thanks!
>>
>> Chub
>>
>>
>>
>>