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Using model 14 as an audo crossfader...

Using model 14 as an audo crossfader...

2006-09-10 by (i think you can figure that out)

A tip:

While the final offset pot of each processor is a powerful tool for
changing the phase relation of incoming AC signals, it can add a DC
offset...that's what that control does.  Xfading from a source with no
DC offset to one that has one will produce a 'thump' sound somewhere
in the travel of the pot (or xfade induced by a control voltage) when
the xfade jumps form ground as reference to something other than
ground.  The larger the offset, the louder the thump.  Your Model 14
ain't broke...you're teling it to do that via control settings. 

If you hate that, then you'll have to remove of the DC offset by
making sure the offset pot is set to the center positions on both
processors so that both LEDs are unlit WHEN NO SIGNAL IS CONNECTED TO
THE INPUTS.

Once you do that there will be no more thump.  A virtual thum-be-gone.

- P

Re: [PLAN_B_analog_blog] Using model 14 as an audo crossfader...

2006-09-10 by Axel Jungkunst

Nice tip: when will the modules arrive at Schneider's Büro in Germany, so we will get a chance to make our own experience :-) ?
All the best
Axel

(i think you can figure that out) schrieb:
Show quoted textHide quoted text

A tip:

While the final offset pot of each processor is a powerful tool for
changing the phase relation of incoming AC signals, it can add a DC
offset...that's what that control does. Xfading from a source with no
DC offset to one that has one will produce a 'thump' sound somewhere
in the travel of the pot (or xfade induced by a control voltage) when
the xfade jumps form ground as reference to something other than
ground. The larger the offset, the louder the thump. Your Model 14
ain't broke...you're teling it to do that via control settings.

If you hate that, then you'll have to remove of the DC offset by
making sure the offset pot is set to the center positions on both
processors so that both LEDs are unlit WHEN NO SIGNAL IS CONNECTED TO
THE INPUTS.

Once you do that there will be no more thump. A virtual thum-be-gone.

- P


Re: [PLAN_B_analog_blog] Using model 14 as an audio crossfader...

2006-09-10 by phil hendricks

thanks Peter!
my m14 only has one SSM2164 yet the info states it has a pair of them?
What gives?
there's space on the 2nd PCB for another.
Just curious, so far it seems to work as expected and is proving to be a
most essential module.
This thing is great a huge hit. thanks!
it's just so darned(fucking) useable.
i think we all need at least two, one dedicated to audio and for CV.
best,
phil




On 9/9/06 7:15 PM, "(i think you can figure that out)"
<peter@buzzclick-music.com> wrote:

> A tip:

Re: Using model 14 as an audio crossfader...

2006-09-10 by (i think you can figure that out)

Phil - I'm really glad you did this module. You know what you're
doin', which mens you can spot a dud a mile away. but...

..your's only has one 2164? and it works?

Just kiddin'!

When i wrote that blurb the final circuit hadn't been completed yet. 
Thanks for reminding me I need to change this. Turned out we only
needed one.  

Regarding the missing components on one of the boards - If you've
noticed, the M14 consists of two identical boards.  Yet only one is
fully populated.  The section on board 2 that isn't populated is the
crossfader (only need one per board).  It's less expensiive to order
twice the qty of one board type than two different boards. That's why
we went this route.  The M14 is expensive, there's a lot in there and
I wanted to keep it as affordable as possible.  

You may also notice a nifty jumper matrix in front of each pot on the
PCB - this is how we handled mounting the pots on opposite sides of
the boards while keeping the polarity correct on each.  You route the
jumpers one way on one board, and switch the jumper locations on the
other board so that the same end of the pot goes to the same modes in
the circuit.  There's another matrix coming on the model 16 - even
more complex.  The bottom pot of each of the filter boards (there are
three) serves a completely different function on each (b1 it's a level
pot, b2 it's a resonance control, b3 it's the sweeper) and the matrix
is used to route each pot into the correct componentry to do the task
we need it to do. SO on the model 16, there are three identical boards
which keep sthe price much lower. Kind of proud of how that worked out.

- P  




--- In PLAN_B_analog_blog@yahoogroups.com, phil hendricks <ph@...> wrote:
Show quoted textHide quoted text
>
> thanks Peter!
> my m14 only has one SSM2164 yet the info states it has a pair of them?
> What gives?
> there's space on the 2nd PCB for another.
> Just curious, so far it seems to work as expected and is proving to be a
> most essential module.
> This thing is great a huge hit. thanks!
> it's just so darned(fucking) useable.
> i think we all need at least two, one dedicated to audio and for CV.
> best,
> phil
> 
> 
> 
> 
> On 9/9/06 7:15 PM, "(i think you can figure that out)"
> <peter@...> wrote:
> 
> > A tip:
>

Re: Using model 14 as an audio crossfader...

2006-12-10 by jalmari3

> If you hate that, then you'll have to remove of the DC offset by
> making sure the offset pot is set to the center positions on both
> processors so that both LEDs are unlit WHEN NO SIGNAL IS CONNECTED TO
> THE INPUTS.

> Once you do that there will be no more thump.  A virtual thum-be-gone.

> - P

How accurately does this work in practice? Does the offset knob have 
a "dead spot" in center position?

I am considering to get a Model 14 to replace two mixers (for CV and 
audio). Of course, it can do other things too.

Best regards
Jari Jokinen

Re: Using model 14 as an audio crossfader...

2006-12-13 by (i think you can figure that out)

I'm going to answer these based on what I think you may be referring to here.  If I'm wrong 
please calrify and I will address your questions:

Dead spot - If you're meaning does it have an amplitude drop in center position when 
crossfading two audio signals, yes it does, but it's insignificant - only  a half dB - which as 
you know is inaudible, being about a 1/4 the energy required for the human ear to 
recognize a drop in amplitude and well within what's considered equal power transfer.  In 
comparison, two crossfaded linear VCAs without the compensation circuitry found in the 
M14 will yield a 3dB drop at center. 

Accuracy:  If what you're speaking about is in regard to the relative amplitude levels of the 
A and B inputs when the xfade is at center, then it's completely accurate.  The two VCAs 
used in the crossfader are ultra linear. When the crossfade pot is at center, it will open the 
A and B VCA exactly the same amount, yet both are cheated 2.5 dB positive from about 11 
to 1 o' clock (meaning pot position) to remove the audible dead spot (see above).  The 
elbow of this cheat circuit is soft - you won't hear a sudden bump in amplitude.  It's a 
seamless transition.

In order for this to work successfully however, THE SIGNAL LEVELS INTO THE A/B INPUTS 
MUST BE THE SAME AMPLITUDE.  Amplitude inequalities between the two inputs will 
obviously cause an offset (if your A signal is louder than your B signal going in, then the 
mid point crossfade will favor the A side).  If this is the case, you can easily compensate by 
cheating the pan pot slightly to favor the B side, which is why we decided not to use a 
center detent pot for the xfader.

hope this helps -

- P






--- In PLAN_B_analog_blog@yahoogroups.com, "jalmari3" <jari.jokinen@...> wrote:
>
> > If you hate that, then you'll have to remove of the DC offset by
> > making sure the offset pot is set to the center positions on both
> > processors so that both LEDs are unlit WHEN NO SIGNAL IS CONNECTED TO
> > THE INPUTS.
>
> > Once you do that there will be no more thump.  A virtual thum-be-gone.
>
> > - P
>
> How accurately does this work in practice? Does the offset knob have
> a "dead spot" in center position?
>
> I am considering to get a Model 14 to replace two mixers (for CV and
> audio). Of course, it can do other things too.
>
> Best regards
> Jari Jokinen
>

______________
Peter Grenader
e: peter@ear-group.net
p: 866-755-4468 (818 761-9906)
w: http://www.ear-group.net

Re: [PLAN_B_analog_blog] Re: Using model 14 as an audio crossfader...

2006-12-13 by John

So I\u2019ve never really looked at the M14 closely. I read in Peter\u2019s post that there are some linear VCA\u2019s in there. Can the M14 be used as a conventional VCA?

Regards,
John


On 12/13/06 1:32 PM, "(i think you can figure that out)" wrote:

Show quoted textHide quoted text





I'm going to answer these based on what I think you may be referring to here. If I'm wrong
please calrify and I will address your questions:

Dead spot - If you're meaning does it have an amplitude drop in center position when
crossfading two audio signals, yes it does, but it's insignificant - only a half dB - which as
you know is inaudible, being about a 1/4 the energy required for the human ear to
recognize a drop in amplitude and well within what's considered equal power transfer. In
comparison, two crossfaded linear VCAs without the compensation circuitry found in the
M14 will yield a 3dB drop at center.

Accuracy: If what you're speaking about is in regard to the relative amplitude levels of the
A and B inputs when the xfade is at center, then it's completely accurate. The two VCAs
used in the crossfader are ultra linear. When the crossfade pot is at center, it will open the
A and B VCA exactly the same amount, yet both are cheated 2.5 dB positive from about 11
to 1 o' clock (meaning pot position) to remove the audible dead spot (see above). The
elbow of this cheat circuit is soft - you won't hear a sudden bump in amplitude. It's a
seamless transition.

In order for this to work successfully however, THE SIGNAL LEVELS INTO THE A/B INPUTS
MUST BE THE SAME AMPLITUDE. Amplitude inequalities between the two inputs will
obviously cause an offset (if your A signal is louder than your B signal going in, then the
mid point crossfade will favor the A side). If this is the case, you can easily compensate by
cheating the pan pot slightly to favor the B side, which is why we decided not to use a
center detent pot for the xfader.

hope this helps -

- P

--- In PLAN_B_analog_blog@yahoogroups.com , "jalmari3" wrote:
>
> > If you hate that, then you'll have to remove of the DC offset by
> > making sure the offset pot is set to the center positions on both
> > processors so that both LEDs are unlit WHEN NO SIGNAL IS CONNECTED TO
> > THE INPUTS.
>
> > Once you do that there will be no more thump. A virtual thum-be-gone.
>
> > - P
>
> How accurately does this work in practice? Does the offset knob have
> a "dead spot" in center position?
>
> I am considering to get a Model 14 to replace two mixers (for CV and
> audio). Of course, it can do other things too.
>
> Best regards
> Jari Jokinen
>

______________
Peter Grenader
e: peter@ear-group.net
p: 866-755-4468 (818 761-9906)
w: http://www.ear-group.net




Re: Using model 14 as an audio crossfader...

2006-12-13 by jalmari3

--- In PLAN_B_analog_blog@yahoogroups.com, "(i think you can figure 
that out)" <peter@...> wrote:
>
> 
> I'm going to answer these based on what I think you may be 
referring to here.
<Lots of good info snipped>

Sorry! I should have presented my question clearer:

Lets say M14 is used simply as a two independent 3 to 1 CV/audio 
mixers. In such case DC offset (at the Sum outputs) might be unwanted 
and thus the DC offset knobs would need to be at 12 o'clock. Both 
leds should be grey then.

I just wonder, if there are practical problems in this situation, 
such as very sensitive knob settings or DC offset not being exactly 
zero. If not, then the M14 can replace two mixers (and of course 
offer extra features).


Best regards
Jari Jokinen

Re: Using model 14 as an audio crossfader...

2006-12-14 by (i think you can figure that out)

Yes.

Crossfading to nothing will give you an ultra quiet, ultra linear VCA for both CVs and audio signals.  To do this, insert a signal into either the input B or Processor B, making sure there's nothing in the A inject or A Processor inputs and that that offset is at 12 o' clock. use the xcrossfade pots as a manual level and the VC Xfade input as the control voltage input.

Works great.

(we have another non-filtered (non M13 type LPF) VCA coming shortly.  More on that at 
Namm...


If you want an inverted VCA in which the amplitude gets louder as the CV goes lower, then repeat the above but input the signal to the A inject input or A processor.


- P



--- In PLAN_B_analog_blog@yahoogroups.com, John <inform3r@...> wrote:
Show quoted textHide quoted text
>
>     So I¹ve never really looked at the M14 closely. I read in Peter¹s post
> that there are some linear VCA¹s in there. Can the M14 be used as a
> conventional VCA?
> 
>     Regards,
>     John
> 
> 
> On 12/13/06 1:32 PM, "(i think you can figure that out)"
> <peter@...> wrote:
> 
> >  
> >  
> >  
> > 
> > 
> > I'm going to answer these based on what I think you may be referring to here.
> > If I'm wrong 
> > please calrify and I will address your questions:
> > 
> > Dead spot - If you're meaning does it have an amplitude drop in center
> > position when 
> > crossfading two audio signals, yes it does, but it's insignificant - only  a
> > half dB - which as
> > you know is inaudible, being about a 1/4 the energy required for the human ear
> > to 
> > recognize a drop in amplitude and well within what's considered equal power
> > transfer.  In 
> > comparison, two crossfaded linear VCAs without the compensation circuitry
> > found in the 
> > M14 will yield a 3dB drop at center.
> > 
> > Accuracy:  If what you're speaking about is in regard to the relative
> > amplitude levels of the
> > A and B inputs when the xfade is at center, then it's completely accurate.
> > The two VCAs 
> > used in the crossfader are ultra linear. When the crossfade pot is at center,
> > it will open the 
> > A and B VCA exactly the same amount, yet both are cheated 2.5 dB positive from
> > about 11 
> > to 1 o' clock (meaning pot position) to remove the audible dead spot (see
> > above).  The 
> > elbow of this cheat circuit is soft - you won't hear a sudden bump in
> > amplitude.  It's a
> > seamless transition.
> > 
> > In order for this to work successfully however, THE SIGNAL LEVELS INTO THE A/B
> > INPUTS 
> > MUST BE THE SAME AMPLITUDE.  Amplitude inequalities between the two inputs
> > will 
> > obviously cause an offset (if your A signal is louder than your B signal going
> > in, then the 
> > mid point crossfade will favor the A side).  If this is the case, you can
> > easily compensate by
> > cheating the pan pot slightly to favor the B side, which is why we decided not
> > to use a 
> > center detent pot for the xfader.
> > 
> > hope this helps -
> > 
> > - P
> > 
> > --- In PLAN_B_analog_blog@yahoogroups.com
> > <mailto:PLAN_B_analog_blog%40yahoogroups.com> , "jalmari3" <jari.jokinen@>
> > wrote:
> >> >
> >>> > > If you hate that, then you'll have to remove of the DC offset by
> >>> > > making sure the offset pot is set to the center positions on both
> >>> > > processors so that both LEDs are unlit WHEN NO SIGNAL IS CONNECTED TO
> >>> > > THE INPUTS.
> >> >
> >>> > > Once you do that there will be no more thump.  A virtual thum-be-gone.
> >> >
> >>> > > - P
> >> >
> >> > How accurately does this work in practice? Does the offset knob have
> >> > a "dead spot" in center position?
> >> >
> >> > I am considering to get a Model 14 to replace two mixers (for CV and
> >> > audio). Of course, it can do other things too.
> >> >
> >> > Best regards
> >> > Jari Jokinen
> >> >
> > 
> > ______________
> > Peter Grenader
> > e: peter@... <mailto:peter%40ear-group.net>
> > p: 866-755-4468 (818 761-9906)
> > w: http://www.ear-group.net
> > 
> >  
> >
>

Re: Using model 14 as an audio crossfader...

2006-12-14 by (i think you can figure that out)

The offset pots are linear - there's no flat spot  or 'de-linear' zone hovering fore and aft 
around 12 o clock, but i've found it very workable regardless.  The inputs are scaled so 
that full positive on the channel input pots will yield no attenuation at the sum outs - what 
goes in is coming out.  One can easily dail in the offset to null knowing this. 



--- In PLAN_B_analog_blog@yahoogroups.com, "jalmari3" <jari.jokinen@...> wrote:
Show quoted textHide quoted text
>
> --- In PLAN_B_analog_blog@yahoogroups.com, "(i think you can figure 
> that out)" <peter@> wrote:
> >
> > 
> > I'm going to answer these based on what I think you may be 
> referring to here.
> <Lots of good info snipped>
> 
> Sorry! I should have presented my question clearer:
> 
> Lets say M14 is used simply as a two independent 3 to 1 CV/audio 
> mixers. In such case DC offset (at the Sum outputs) might be unwanted 
> and thus the DC offset knobs would need to be at 12 o'clock. Both 
> leds should be grey then.
> 
> I just wonder, if there are practical problems in this situation, 
> such as very sensitive knob settings or DC offset not being exactly 
> zero. If not, then the M14 can replace two mixers (and of course 
> offer extra features).
> 
> 
> Best regards
> Jari Jokinen
>

Re: Using model 14 as an audio crossfader...

2006-12-14 by (i think you can figure that out)

The offset pots are linear - there's no flat spot  or 'de-linear' zone hovering fore and aft 
around 12 o clock, but i've found it very workable regardless.  The inputs are scaled so 
that full positive on the channel input pots will yield no attenuation at the sum outs - what 
goes in is coming out.  One can easily dail in the offset to null knowing this. 



--- In PLAN_B_analog_blog@yahoogroups.com, "jalmari3" <jari.jokinen@...> wrote:
Show quoted textHide quoted text
>
> --- In PLAN_B_analog_blog@yahoogroups.com, "(i think you can figure 
> that out)" <peter@> wrote:
> >
> > 
> > I'm going to answer these based on what I think you may be 
> referring to here.
> <Lots of good info snipped>
> 
> Sorry! I should have presented my question clearer:
> 
> Lets say M14 is used simply as a two independent 3 to 1 CV/audio 
> mixers. In such case DC offset (at the Sum outputs) might be unwanted 
> and thus the DC offset knobs would need to be at 12 o'clock. Both 
> leds should be grey then.
> 
> I just wonder, if there are practical problems in this situation, 
> such as very sensitive knob settings or DC offset not being exactly 
> zero. If not, then the M14 can replace two mixers (and of course 
> offer extra features).
> 
> 
> Best regards
> Jari Jokinen
>

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