MOTM

I put together a quick 1U module version of the NE-10400/10500
(GX-1) filter. I'll have it at AHMW this weekend, where Stooge Larry will
provide a panel I can actually mount the switches on. ;) (Orange switch
is HP/LP mode select, green switch is full or half keyboard tracking...a
Yamaha thing where they seem to like to operate the HP filter at 1/2
tracking of the LP filter...)

http://www.cs80.com/gx1_module.jpg

Yes, if you look closely you see that I just made a host board to plug
the submodule into. And not a single op-amp anywhere...

Crow
/**/

How many of these were in the GX1? I guess 8 for each of the two
bigger manuals, just curious.
Enrico

--- In motm@yahoogroups.com, The Old Crow <oldcrow@o...> wrote:
>
> I put together a quick 1U module version of the NE-10400/10500
> (GX-1) filter. I'll have it at AHMW this weekend, where Stooge
Larry will
> provide a panel I can actually mount the switches on. ;) (Orange
switch
> is HP/LP mode select, green switch is full or half keyboard
tracking...a
> Yamaha thing where they seem to like to operate the HP filter at
1/2
> tracking of the LP filter...)
>
> http://www.cs80.com/gx1_module.jpg
>
> Yes, if you look closely you see that I just made a host board to
plug
> the submodule into. And not a single op-amp anywhere...
>
> Crow
> /**/

--- In motm@yahoogroups.com, The Old Crow <oldcrow@o...> wrote:

> I put together a quick 1U module version of the NE-10400/10500
> (GX-1) filter.

Is this quite different from the CS80 filter? and will this also
become a MOTM module? Please say yes :-)
Enrico (Sicily)

A single GX1 voice has four filters (HP, BP, and a HP-LP pair). There
are one voices per note (up to eight notes) per 61-key manual, a single
voice for the solo manual, and three voices for the pedalboard (though the
pedals are still monophonic). So, if you add it all up, there are 4
filters x 8 notes x 2 polyphonic manuals + 4 for solo manual + 12 for
pedalboard. That is 70 filters. Now you begin to see why the GX-1
weighs 300kg.

The GX1 filter module in 1U format is a single filter from the HP-LP
pair. You would need two of them to make the actual pair. Since I already
had a CS80 (state variable filter model) filter pair done on the MOTM-480,
I wanted to split the GX1-type (Sallen-Key diode ring) filters into two
modules so that 1) folks could insert other modules into the signal path,
and 2) if this was ever to be a MOTM 'micromodule' it would need to be 1U
and there isn't enough space to do a filter pair with enough basic panel
controls/jacks.

And yes, the CS80 and GX1 filters designs are not the same at all. You
can even do some ring modulator type sounds through the GX1 filter's diode
ring with resonance (I was doing that while testing the module ;), and
overdriving the filter input results in some interesting harmonic
'steps'.

Crow
/**/

On Thu, 18 Mar 2004, edibennardo wrote:

> How many of these were in the GX1? I guess 8 for each of the two bigger
> manuals, just curious. Enrico

> ----- Original Message -----
> From: The Old Crow <oldcrow@...>
> Subject: [motm] Something else to show at AHMW

http://www.cs80.com/gx1_module.jpg

Stooge brackets stike again !!

> Yes, if you look closely you see that I just made a host board to plug
> the submodule into. And not a single op-amp anywhere...

I see. And the reason is because you already had the GX-1 filter module
made up in the small format as a replacement for the original?

Larry

--- In motm@yahoogroups.com, The Old Crow <oldcrow@o...> wrote:

>So, if you add it all up, there are 4 filters x 8 notes x 2
>polyphonic manuals + 4 for solo manual + 12 for pedalboard. That is
>70 filters.

70 filters is astonishing! but your calculation should give 80
filters that is even more astonishing (4x8 + 4x8 + 4 + 12)

> I wanted to split the GX1-type (Sallen-Key diode ring) filters into

two

> modules so that 1) folks could insert other modules into the signal

path,

Not clear, are you just saying that we could use two HP-LP pairs, so
twice the same 1U module? (similar to the use of two 420) or you are
also talking of a second 1U module to duplicate the HP or the BP or
maybe both other two filters of the GX1?
Enrico

Oops, you are correct, forgot to carry the 1...it is 80 filters.

To make one HP-LP pair you would use two of these 1U modules, similar to
using two 420s. There is a switch to select HP/LP, so one is set to HP,
the other to LP, and for true Yamaha effect set the HP filter to 1/2
tracking (and LP tracking to 1).

Of the 4 filters in a GX1 voice, three of them are the same (or nearly
so); those are the NE-10400 and NE-10500 potted modules. The BP filter
(NE-11000), which has voltage-controlled frequency but fixed resonance, I
do not have available to study, though I can infer a great deal from the
other filters.

Crow
/**/

On Thu, 18 Mar 2004, edibennardo wrote:

> --- In motm@yahoogroups.com, The Old Crow <oldcrow@o...> wrote:
>
> Not clear, are you just saying that we could use two HP-LP pairs, so
> twice the same 1U module? (similar to the use of two 420) or you are
> also talking of a second 1U module to duplicate the HP or the BP or
> maybe both other two filters of the GX1?
> Enrico

Speaking of showing new stuff at AHMW, I'll be bringing the new
Encore Freq. Shifter to show and tell...

Moe
http://www.hotrodmotm.com

Paul -

I would like to put in a strong vote for a 1U GX1 MOTM module. The
sound is sufficiently different (and how!) from the 420 to merit
adding it to the lineup and the 1U format makes it doubly attractive
to me.

Would it not look just like the 490 in terms of knobs and jacks?
Seems like it would be 'easy' to add to the product line. What says
everybody? Would this be cool or what?!?

Along those lines, more 1U filters would be good. What about the
ARP filter that was discussed? What about something like a quad
bandpass ala CGS/Cyndustries? Low Pass Gates?

But mostly, 1U GX1!

Mike

Well, if Old Crow says, OK...then OK!

The ARP 2600 VCF is a *definite YES* for this fall.

Paul S.

On Friday 19 March 2004 22:27, synth1@... wrote:

> Well, if Old Crow says, OK...then OK!
>
> The ARP 2600 VCF is a *definite YES* for this fall.
>

Wowie, on both of the above. :)

- Robert

--- In motm@yahoogroups.com, synth1@a... wrote:

> Well, if Old Crow says, OK...then OK!

A dream come true?
Enrico

I'm a go on both of these.

George

----- Original Message -----
From: <synth1@...>
To: "Mike Marsh" <mmarsh@...>
Cc: <motm@yahoogroups.com>
Sent: Friday, March 19, 2004 4:27 PM
Subject: [motm] GX1 VCF


> Well, if Old Crow says, OK...then OK!
>
> The ARP 2600 VCF is a *definite YES* for this fall.
>
> Paul S.

Hi all--

------------------

>Mike:
>I would like to put in a strong vote for a 1U GX1 MOTM module. The sound

is

>sufficiently different (and how!) from the 420 to merit adding it to the
>lineup and the 1U format makes it doubly attractive to me.
>Larry:
>Your views are right on Mike. I want two. Mechanically, it is like a
>MOTM-190 with the switch positions.

Well, me too, please! I enjoy lots of Yamaha (don't get me started on a kit
list) and would be *very happy* to welcome a 1U GX-1 module for Dr. Modular.

If it seems as though this might not come through as an 'official' MOTM
module, then I'd be similarly happy to welcome something we can get
separately and put behind a Stooge Panel!

<Again bowing to Crow's Yamaha-genius-ness for making this a viable topic of
discussion>

Frank Vanaman

On Sunday 21 March 2004 23:55, J. Larry Hendry wrote:

> > ----- Original Message -----
> > From: Mike Marsh <mmarsh@...>
>
> I would like to put in a strong vote for a 1U GX1 MOTM
> module. The sound is sufficiently different (and how!)
> from the 420 to merit adding it to the lineup and the 1U
> format makes it doubly attractive to me.

Just curious, why is the GX1 MOTM filter mentioned together
with the '420? Just because both are 12dB filters?

- Robert

> ----- Original Message -----
> From: Mike Marsh <mmarsh@...>

I would like to put in a strong vote for a 1U GX1 MOTM module. The sound is
sufficiently different (and how!) from the 420 to merit adding it to the
lineup and the 1U format makes it doubly attractive to me.

Your views are right on Mike. I want two. Mechanically, it is like a
MOTM-190 with the switch positions.

Larry

The GX filter is a diode filter (surprisingly), but according to Crow
the usual nastiness is masked out by the highpass / lowpass serial
configuration.

If you run it alone, you should be able to get some sounds that are
not possible when in the GX configuration. Note however that the
resonance is tamed down. There is a trim pot to limit max resonance
that you could abuse I suppose.

Moe

--- In motm@yahoogroups.com, Robert van der Kamp <robnet@w...> wrote:
> On Sunday 21 March 2004 23:55, J. Larry Hendry wrote:
> > > ----- Original Message -----
> > > From: Mike Marsh <mmarsh@w...>
> >
> > I would like to put in a strong vote for a 1U GX1 MOTM
> > module. The sound is sufficiently different (and how!)
> > from the 420 to merit adding it to the lineup and the 1U
> > format makes it doubly attractive to me.
>
> Just curious, why is the GX1 MOTM filter mentioned together
> with the '420? Just because both are 12dB filters?
>
> - Robert