MOTM

Yeah Id be nterested in this also, I seem to notice the ranges of the 3 
filters in my 410 as being not parallel, knobwise..  (you get what I mean)

anyone?
Paul?  Im sure you got these as close as posible from the get go, but whats 
the tolerance range of the vactrols?

~Steve M

It's the Vactrols +-20% tolerance and 1 other "non-part" issue. Everyone think hard! 

Paul S.

revtor@... schrieb:
> Yeah Id be nterested in this also, I seem to notice the 
> ranges of the 3  
> filters in my 410 as being not parallel, knobwise..  (you 
> get what I mean) 
> 
> anyone?
> Paul?  Im sure you got these as close as posible from the 
> get go, but whats  
> the tolerance range of the vactrols?

The tolerance is *huge*. And this is part of their character:
Two of them won't sweep exactly in parallel in a log 
frequency scale even with the same CV and with their relative offset 
adjusted for one center frequency. 
If you like, you can adjust the knob on the pot shaft (or add an
internal offset trimmer), but this will only set identical 
knob positions for one frequency (12 o'clock position would be
a reasonable choice).

Gentlemen, this is a *feature*, and I mean it. Thank God for vactrols
which prevent the M-410 (and the Mutron Biphase, and the Schulte
Compact A Phasing, ...) from being as sterile as similar sweeping
filters without vactrols.
Using these things as a sort of fixed filter bank is a nice extra
goodie, but it was made and optimized for more demanding tasks.

(This is not meant against using them as fixed filters. I'm still
blown away from Elhardt's excellent Flute/Recorder patch !)

JH.

On Tue, 18 Dec 2001, Paul Schreiber wrote:

> It's the Vactrols +-20% tolerance and 1 other "non-part" issue. Everyone think hard! 
> 
Different frequency 'bands'.

> 
> > It's the Vactrols +-20% tolerance and 1 other "non-part" issue. Everyone think hard! 
> > 
> Different frequency 'bands'.

Partial credit, keep thinking.

Paul S.

At 7:47 PM +0100 12/18/01, jhaible@... wrote:
>
>The tolerance is *huge*. And this is part of their character:
>Two of them won't sweep exactly in parallel in a log
>frequency scale even with the same CV and with their relative offset
>adjusted for one center frequency.
>If you like, you can adjust the knob on the pot shaft (or add an
>internal offset trimmer), but this will only set identical
>knob positions for one frequency (12 o'clock position would be
>a reasonable choice).

That's what I said.  Besides, if the vactrols have a 20% tolerance, and the
pots have a 10% tolerance, it could add up to a significant difference.

>Gentlemen, this is a *feature*, and I mean it. Thank God for vactrols
>which prevent the M-410 (and the Mutron Biphase, and the Schulte
>Compact A Phasing, ...) from being as sterile as similar sweeping
>filters without vactrols.

God invented the vactrol?? ;)

>Using these things as a sort of fixed filter bank is a nice extra
>goodie, but it was made and optimized for more demanding tasks.
>
>(This is not meant against using them as fixed filters. I'm still
>blown away from Elhardt's excellent Flute/Recorder patch !)

I often use mine for filter FM :)

> That's what I said.  Besides, if the vactrols have a 20% tolerance, and
the
> pots have a 10% tolerance, it could add up to a significant difference.

Nit picking here, the pot's tolerance will only have a minor influence.
(They are used as variable dividers, not as rheostats.)

> God invented the vactrol?? ;)

He he, God invented man, and man invented vactrols (;->).

Sorry if anything from my mails sounded pompous - I just wanted
to say that it's all a direct consequence of using Vactrols,
and the filter would not be what it is, without them.

JH.

Speaking of the 410, I have 2 of them and on my second one I installed a
switch at R68 to move it in and out of the circuit but it seems that the 410
will only work with the switch on or R68 in circuit and yes I am using a
preamp with my external audio sources.  Any ideas or is this not worth
trying to figure out?  It works with both MOTM VCO's and external sources so
it seems.
Thanks
JB

-----Original Message-----
From: jhaible@... [mailto:jhaible@...]
Sent: Tuesday, December 18, 2001 2:27 PM
To: mark@...
Cc: motm@yahoogroups.com
Subject: Re: [motm] Re: tweaking the 410


> That's what I said.  Besides, if the vactrols have a 20% tolerance, and
the
> pots have a 10% tolerance, it could add up to a significant difference.

Nit picking here, the pot's tolerance will only have a minor influence.
(They are used as variable dividers, not as rheostats.)

> God invented the vactrol?? ;)

He he, God invented man, and man invented vactrols (;->).

Sorry if anything from my mails sounded pompous - I just wanted
to say that it's all a direct consequence of using Vactrols,
and the filter would not be what it is, without them.

JH.




 

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At 9:26 PM +0100 12/18/01, jhaible@... wrote:
>
>> That's what I said.  Besides, if the vactrols have a 20% tolerance, and
>> the pots have a 10% tolerance, it could add up to a significant
>> difference.
>
>Nit picking here, the pot's tolerance will only have a minor influence.
>(They are used as variable dividers, not as rheostats.)

Are you saying the that the difference is spread evenly across the
resistive element??  Yes, then it wouldn't matter for a voltage divider.
I'm no materials engineer, but I'm thinking if they could do that, they
could make them better than 10%.  Then again, I could be wrong.

>> God invented the vactrol?? ;)
>
>He he, God invented man, and man invented vactrols (;->).

So the Three Wise Men weren't Bob, Tom, and Harold?? :)

>Sorry if anything from my mails sounded pompous -

Oh, you'd have to stand in line to sound pompous on this list :)

>I just wanted to say that it's all a direct consequence of using Vactrols,
>and the filter would not be what it is, without them.

Well, thank God/Korg/Schreiber for that!!  I love the 410.  I'm thinking it
would be popular even as a stand-alone product.

> >He he, God invented man, and man invented vactrols (;->).
>
> So the Three Wise Men weren't Bob, Tom, and Harold?? :)

The vactrol resonator has its origin at Korg, so that would
be "the magi from the east". (;->)

JH.

At 7:47 PM +0100 18/12/01, jhaible@... wrote:
>The tolerance is *huge*. And this is part of their character:
>Two of them won't sweep exactly in parallel in a log
>frequency scale even with the same CV and with their relative offset
>adjusted for one center frequency.
>If you like, you can adjust the knob on the pot shaft (or add an
>internal offset trimmer), but this will only set identical
>knob positions for one frequency (12 o'clock position would be
>a reasonable choice).

I suppose that would work, but unfortunately, I'm far too anal about 
having my knobs lined up with the tick marks. I'm one of those people 
who tweaked their 110 as per Stooge Larry's mod 
(http://www.wiseguysynth.com/larry/mods/110mod.htm) even before it 
got off the bench.

>Gentlemen, this is a *feature*, and I mean it. Thank God for vactrols
>which prevent the M-410 (and the Mutron Biphase, and the Schulte
>Compact A Phasing, ...) from being as sterile as similar sweeping
>filters without vactrols.
>Using these things as a sort of fixed filter bank is a nice extra
>goodie, but it was made and optimized for more demanding tasks.

OK, so perhaps I need an "education" about how to use the 410 besides 
as a fixed filter bank. Anybody want to enlighten me as to other uses 
for the 410?

At 6:26 PM -0700 12/19/01, Scott Juskiw wrote:
>
>OK, so perhaps I need an "education" about how to use the 410 besides
>as a fixed filter bank. Anybody want to enlighten me as to other uses
>for the 410?

I'm surprised no one else has tried to answer this.  While I am sure there
are others on the list who could offer better answers, I'm willing to give
it a shot.

You can use the 410 as a fixed filter bank -- just turn the LFO depth down
to zero.  It's just that you can't control the three filters independently,
or get them to track well together.  You can also use it a single BPF by
using only one of its outputs,

The most obvious use for the 410 is a "phaser".  I tend to use slow LFO
rates with shallow depth, and faster LFO rates with increasing depth.  You
can go from one effect to the other with an 800 controlling both, or use
both of the 800 outputs to morph between an annoying noise and something
pretty.

The three separate outputs can be mixed at the board to create stereo
effects. This capability can be increased by sending these outputs through
phase inverters or short delays, or by modulating the RATE control with
another LFO, such as the 320.

By increasing DEPTH, setting the FREQ knobs farther apart, and MIX set all
the way wet, you can create "delay" effects with a constant or slowly
changing input -- as the sound appears then reappears.

Notice that SWEEP is normalled to a fixed voltage using a switched jack.
As such, it serves as a ganged control for the frequency of the three
filters.  When a plug is inserted, the SWEEP knob becomes an input
attenuator.

I frequently use the 410 for filter FM by patching an oscillator into
SWEEP.  By setting DEPTH to zero, and using an oscillator harmonically
related to the input, this becomes more melodically useful.  Even if it
isn't, you can sample it or run it through a pitch shifter.  Note that the
three individual outputs are still available to be mixed and processed
separately.  The internal LFO's can be used as well to add more stereo
animation or create long evolving patches.  You can also patch one or more
of the three outputs back into SWEEP, RATE, or DEPTH.

An interesting aspect is that the frequencies modulating the filters seem
inherently limited.  This dampening effect seems to reduce the incidence of
high frequency partials easily encountered with oscillator FM, even when
using feedback.

In using the 410, one thing to keep in mind is that it is very easy to set
frequency of the filters above the audible range.  Also, like most
"phasers"  it's not good at processing low frequencies, and in order to
make it a truer "clone" it has a HPF at its input.  I've thought about
bypassing that filter, but I've decided that I'm happy with it just the way
it is.

I also sometimes add the MIX OUT to the board mix but with no wet 
signal at all.  By increasing or decreasing the amount of dry, you 
can get better control of the overall sound.  This is great for 
phaser-like effects.

Don't forget to play with the LFO switch.  I almost always use the 
DUAL REV mode since it produces complexity, but the other modes work 
weel with some voices, too.

Mike

--- In motm@y..., mark@i... wrote:
> ...
> The three separate outputs can be mixed at the board to create 
stereo
> effects. This capability can be increased by sending these outputs 
through
> phase inverters or short delays, or by modulating the RATE control 
with
> another LFO, such as the 320.
> ...

At 12:01 PM -0500 2002/01/07, mark@... wrote:

>I'm surprised no one else has tried to answer this.  While I am sure there
>are others on the list who could offer better answers, I'm willing to give
>it a shot.

Thanks for your input, I'll definately try out some of your ideas. 
Since my original post I've had ample opportunity to beat the hell 
out of my 410. My current favourite trick is to use a 410 in the 
feedback loop of a 420 to enhance the Q of the bandpass filters.

"some audio signal" feeds 420 IN1
420 OUT feeds 410 IN
410 MIX OUT feeds 420 IN2

Set the 420 to LP mode, tweak the 420 INs, RES, and FREQ as necessary 
to get very narrow Q from the 410. A great way to extract specific 
bands from a pink noise source.

Hey, this is a good idea. Do you use the LFOs on the 410 in this 
patch.  I'm gonna try that as soon as I get home...

You could do this with the 440, too.

Mike

--- In motm@y..., Scott Juskiw <scott@t...> wrote:
> At 12:01 PM -0500 2002/01/07, mark@i... wrote:
> 
> >I'm surprised no one else has tried to answer this.  While I am 
sure there
> >are others on the list who could offer better answers, I'm 
willing to give
> >it a shot.
> 
> Thanks for your input, I'll definately try out some of your ideas. 
> Since my original post I've had ample opportunity to beat the hell 
> out of my 410. My current favourite trick is to use a 410 in the 
> feedback loop of a 420 to enhance the Q of the bandpass filters.
> 
> "some audio signal" feeds 420 IN1
> 420 OUT feeds 410 IN
> 410 MIX OUT feeds 420 IN2
> 
> Set the 420 to LP mode, tweak the 420 INs, RES, and FREQ as 
necessary 
> to get very narrow Q from the 410. A great way to extract specific 
> bands from a pink noise source.

At 11:12 PM +0000 2002/01/07, mmarsh100 wrote:
>Hey, this is a good idea. Do you use the LFOs on the 410 in this
>patch.  I'm gonna try that as soon as I get home...

I'm not using the LFOs in this patch, but I use an 800 to SWEEP the 
410 very gently as needed.

>
>You could do this with the 440, too.
>

True, I just don't have a 440 yet.

Hey, that's pretty wacky!  Gonna try it with the 440...

--- In motm@y..., Scott Juskiw <scott@t...> wrote:

> At 11:12 PM +0000 2002/01/07, mmarsh100 wrote:
> >Hey, this is a good idea. Do you use the LFOs on the 410 in this
> >patch.  I'm gonna try that as soon as I get home...
> 
> I'm not using the LFOs in this patch, but I use an 800 to SWEEP the 
> 410 very gently as needed.
> 
> >
> >You could do this with the 440, too.
> >
> 
> True, I just don't have a 440 yet.