'morning Roel,
--- In SergeModular@yahoogroups.com, "roelelec" <r.steverink@...> wrote:
>
> Hi Guy,
>
> So the In signal gets attenuated when you turn the knob to the plus (CW) and of course inverts when you turn it ccw.
No. And yes.
The incoming signal doesn't get attenuated when you turn the pot either CW or CCW. The signal is fully attenuated (=0) when the pot is at its center position. Turning the pot either way "opens" the signal more and more, until you arrive at the full CW- or CWW positions, where the signal reaches its maximum level, or the inverse thereof.
But I'm sure you knew this; you just misplaced the word "attenuated". :-)
> Isn't it strange that this particular processed pot doesn't amplify like all the others do? I mean in the Gold book and other places there's written that processed pots can attenuate, amplify and or invert a cv voltage!
They 'could' or they 'can', yes.
In this case, no.
AFAIK, most attenuator pots on a Serge system do not provide for extra gain, except where it makes more sense (VCA's, etc.). In that case, it's called... Gain. Note however that "gain" also doesn't necessarily mean there will be a possible greater gain than the original signal. Amplifying a signal [in a modular synth] can be a tricky business... what with those vulnerable speakers.
In other words: an attenuator pot allows you to manually set a signal between 'nothing' and 'all', but not 'more'. A gain pot *could* potentially make the signal larger, but not necessarily so. It depends on the application. The electronic circuitry behind both is totally different. An attenuator is (mostly) a passive device, whereas a gain circuit is an active device: it amplifies a signal, and sometimes it can amplify above unity gain (=bigger than the original).
> I always thought DC voltage (non-fluctuating) is always below zero (subaudio) and AC voltage (fluctuating) above zero (audio), but I discovered that DC voltage can be in the plus also!
DC can be fluctuating too. A LFO comes to mind...
Look at it this way: AC (Alternating Current) fluctuates around the zero axis. DC doesn't.
When an AC signal isn't fluctuating *centered* around the zero axis, it has as DC component (offset), which is mostly A Bad Thing.
To make matters more complicated, a DC signal can be "shifted" around and about the zero axis as well. This is what the SB buffer can do (with the -5/+5 pot).
> Is there no correlation with the hearing sound?
When in the audio range, there is no correlation to what you hear when a signal is AC or DC. A triangle audio wave sounds exactly the same when it's either DC- or AC-coupled (respectively: above or below the zero axis, or centered around that axis).
When the signal is sub-audio, and it is used as a modulation source, it makes a big difference. However, in the world of Serge, you can easily adjust that difference by shifting that low frequency up or down. Again, the Scaling Buffers come to mind...
> I mean on the NTO, the sinus has a black ring which means it outputs between -2,5 and + 2,5 volts
AC-coupled, yes.
and triangle and saw have blue rings which indicates 0 - +5 volt.
DC-coupled :-)
Does this mean -2,5 - 0 of the sinus is DC which as soon as it goes higher then zero, it turns into AC? Or is this nonsense!
> Can you please explain this!
I understand where your confusion comes from. And Serge's paradigm of being able to shift signals at will doesn't make it easier.
I'm not very good at explaining this, though. Perhaps you could look up a few things in Wikipedia ?
> Thanks, yes now I understand what scaling in this context means and does! But I suspect that scaling on another funktion is more complex than that.
It can be dauntingly complex, yes. See above about the Serge paradigm. But this is one of the strengths of a Serge system: it allows you to freely "play with signals", regardless if they're DC or AC. A Serge system doesn't really make a difference between audio and low frequencies. It's just... a signal, and it is left up to you as to what to do with those signals. This in sharp contrast with a Buchla system, where audio and CV are strictly separated.
> Which panels does your Serge contain?
Less than it matters. Or more than it matters. :)
_g
>
> Cheers,
>
> Roel
>
>
>
>
> --- In SergeModular@yahoogroups.com, "Guy" <guy@> wrote:
> >
> > Hi Roel,
> >
> > What you've already said about the SB, is true (except for the "amplify" part).
> > The lower pot (-/+) attenuates the In signal, and/or inverts it, in a gradual way.
> > Turning that pot fully CW or CCW does *not* add gain; it merely passes the incoming signal completely.
> > The upper pot (-5/+5) simply *adds* a positive or negative steady DC voltage to what is fed into the [attenuated] Input . So it "scales" the input either up or down (het werkwoord 'scalen' betekent o.a. omhoog- of omlaag gaan; bvbd. 'scaling a wall' betekent 'op een muur klimmen').
> > Used on its own -- that is, without any signal fed to the Input -- it just puts out that steady DC voltage. In that sense, it is indeed a CV source; only, it's a *steady* and manually-controlled CV source. There's no LFO or something hidden underneath it...
> >
> > And that's it.
> > Just a simple utility module, but nonetheless a powerful one.
> >
> > The most common use of the SB, is when you need to attenuate (or 'attenuvert', as it is sometimes called nowadays) a signal fed to an input which has no attenuator pot (which happens frequently on Serge modules).
> > I sometimes use the -5/+5 pot simply to tune oscillators, by setting it to exact voltages (1V, 2V...), but of course the combination with the processing attenuator makes it seriously more funky.
> > I use the Scaling Buffers in almost every patch.
> >
> > Hope that helps,
> > _g
> >
> >
> > --- In SergeModular@yahoogroups.com, "roelelec" <r.steverink@> wrote:
> > >
> > > Hi all,
> > >
> > > I want to know more about the scaling buffers I have in my Quadslope.
> > > There's little information on the internet, none in the Gold book or in further Serge catalogs.
> > >
> > > I know you can attenuate, amply and invert a signal, due to it's processed pot and you have an offset with a range between -5 and +5 volt.
> > > But what more can you further do with it?
> > >
> > > I thought I can meaby use it as a cv source, but that didn't work.
> > > I didn't got an extra rate knob, just the same only with a broader range.
> > >
> > > And can someone explain me what scaling means?
> > > This word has many connotations, but what does it mean in this regard I don't know?
> > >
> > >
> > > Thanks for any help.
> > >
> > > Cheers,
> > >
> > > Roel
> > >
> >
>