Hiss from VCO

[guest]

do you still have the mixin on this x0x
you could take the vco out
and put it into the mix in
and then listen on the mixout
that will buffer the signal before it goes to the soundcard

otherwise try a shorter cable
or going to a mixing board rather than the computer
or try putting a 100k resistor to ground
from the vco out jack tip

[isak]

actually the VCO out is from the mix in jack, farther on i have 2 mods in that jack.
the first is the VCF CV in, from the tip
the second is the VCO out, from the ring
i cut the trace that goes to pin 3 on J7.
in the begging i was thinking that the VCF mod is doing that somehow and then i checked the mod on other x0x and it was the same so its not the VCF mod.
u want me to do the mod on deferent jack and plug it via the mix in (on a my other x0x)?

[guest]

you can probably keep it on the same jack
but try plugging it into the mixin on another x0x
and listen at the mixout of that x0x

[isak]

ok, i plugged it to the other x0x and it was the same hiss, no change.

[guest]

how does the square wave sound
does it sound like it should but with added noise
or does it sound distorted
does the volume seem right
does it play the right note

is the jack properly grounded

i think i may be out of suggestions

[isak]

how does the square wave sound

it sounds good

does it sound like it should but with added noise
or does it sound distorted

sound like it should but very distorted coz of the very high volume.

does the volume seem right

very high, same goes the saw wave also distorted, very high volume, but it sound good.

does it play the right note

yes

is the jack properly grounded

yes, i checked with my multimeter bip tones.

i think i may be out of suggestions

[guest]

you could try listening through a potentiometer
that way you could knock the signal level down a bit

put a 100k pot at the vco out
one end goes to the signal
the other end goes to ground
and the wiper goes to your mixing board

[isak]

thanks guest, i was thinking adding a pot to the VCO.
Q..
doenst it should be high like that? i mean if i take the VCO and connect it to external VCF or VCA cant i control the volume from there?

[guest]

it depends upon what your plugging it into
most audio devices take 1v signals or so
the vco outputs 5v signals
which will distort
and maybe even damage the input

[isak]

guest,

i just now rememberd that bcbox has this mod and i checked his documants on how he did it.


i didnt understand something here, if "S" goes to (-) of C17 where goes the "T" ? to the (+)?
maybe this will fix the hiss probelm, dont u think?

[guest]

im not sure where T goes
but taking the signal from c17
would be the same as putting in a pot
as it knocks the signal down by 1/100
you will probably need a mixer
to amp the signal before listening to it
but it will definitely sound better from there

[isak]

can i take the signal from c17 and leave c17 on board

another Q..
what is the last component of the VCO chain before the getting to the VCF and can i take the signal from this last component?

[guest]

c17 is the last component
it doesnt matter too much which side
you take the signal from
although the (-) side might be a bit better

[isak]

and i dont need to use some resistors or something ..?

[guest]

if you wanted to put a 1k between c17 and the output
that might be good to protect the x0x
in case you plug the wrong thing in someday
but it shouldnt be necessary for the sound