Emax

A little knowledge can be a dangerous thing.
So you continue down this road of doing what is not recommended.
I recommend you stop and get a meter before you burn something up.
If you burn up the circuit or kill the Emax, don't come complaining!!!

Ted



On Fri, Mar 2, 2012 at 2:02 PM, zrennaya <zrennaya@...> wrote:

> **
>
>
>
> Okay I think I missed the 0-10V part in the manual...I checked now and
> it's there, so my bad!
>
> So now I experimented with my CV source changing the gain on its DC opamp
> and tried to stay on the positive voltage side. Unfortunately I don't have
> a multimeter so I just checked the tolerance of the pedal input on the
> recalibration page and I only used values between the two tolerance limits.
>
> When the recalibration asks for minimum value I can reach Pre:0999 Post:_
> , if I go below that, that's where my CV signal starts to act like the DATA
> slider. As for the maximum value, I can only do Pre:0927 Post:2.
>
> So I calibrated it to these values and if I don't let the CV source go
> beyond the two limits it actually works, but the resolution is rather
> steppy, I'm guessing it's because of the Pre:0999-0927 calibration. So my
> external sine LFO is okay, ramp down is okay-ish but ramp up can only go up
> to a certain rate, after that it disappears, I guess because the sample and
> hold ic can't sample it anymore with this resolution.
>
> I checked the calibration of the right wheel and it goes from
> Pre:0947Post: to Pre:0334Post:2 which seems to be a much higher resolution.
> Actually this popped up another question: I calibrate the right wheel and
> then I assign it to filter cutoff but it wouldn't open and close it all the
> way! If I set the initial filter cutoff value in filter setup to 0, the
> wheel's lowest position closes the filter all the way but it won't open it
> all the way up at the highest position, I have to set the initial value to
> around 40 and that's where it happens, but then it won't close it all the
> way at the lowest position. Can anyone clue me in? Cheers
>
> Sorry for my grammar, I'm from eastern Europe..
>
>
> --- In emax@yahoogroups.com, el macaco <elmacaco@...> wrote:
> >
> >
> > The manual says the pedal takes 0-10 volts, so the problem is the
> negative voltage.
> >
> > The service manual says you can input a voltage to the tip of the plug
> 0-9 volts, or it can be a fedal that varies resistance from the tip to
> ground.
> >
> > try it with a voltage source that only goes 0-5 and see if the same
> trouble occurs.
> >
> >
> >
> >
> >
> >
> > To: emax@yahoogroups.com
> > From: jammie.emma@...
>
> > Date: Fri, 2 Mar 2012 17:31:44 +0000
> > Subject: Re: [emax] Re: Emax pedal input and control voltages
> >
> >
> >
> >
> >
> >
> > i thought that it was when using a pedal
> >
> > if using another device to send cv into the pedal cv then you are asking
> for
> > trouble its not that kind of cv
> >
> > the cv from another device say modular synth will be ground and the cv
> > voltage 0-10v
> >
> > you will damage the cv circuit
> >
> > if you want foot control from external device then just use midi
> >
> > ----- Original Message -----
> > From: "Ted Summers" <djtbs1@...>
> > To: <emax@...m>
> > Sent: Friday, March 02, 2012 4:54 PM
> > Subject: Re: [emax] Re: Emax pedal input and control voltages
> >
> > > If I understand what was said, it was attempted to connect a different,
> > > external device (not a pedal) to send a control voltage onto one of the
> > > connections of the emax pedal input.
> > > If I am wrong in what my understanding is, then ignore this post....
> > >
> > > Well, this is quite simply, an electronics question.
> > >
> > > The Voltage is coming out of 1 contact, and is used as the reference
> by
> > > the
> > > IC.
> > > As the wiper (pedal) is moved, it affects the return voltage in
> reference
> > > to the original voltage signal and (depending on the circuit) the
> > > difference to ground as well.
> > >
> > > To inject a signal from some other device I wouldn't expect that to
> > > necessarily work properly.
> > > There is no guarantee that the other device's reference ground plane
> is
> > > the
> > > same.
> > > That scenario can create a difference in ground potential, a ground
> loop
> > > hum can result, bad value can result, etc.
> > >
> > > Is the other device using the same pin / connections for the ground and
> > > reference?
> > >
> > > If not, there is potential for damage of both units as well, since you
> > > could cause a short or overvoltage condition, exceeding the max voltage
> > > limits of the ICs...
> > >
> > > Just something to think about...
> > >
> > > Ted
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > On Fri, Mar 2, 2012 at 8:30 AM, Chase Smith <plus_321@...> wrote:
> > >
> > >> **
> > >>
> > >>
> > >> My understanding is that the emax sends a cv out of the pedal input
> maybe
> > >> on the ring of a trs jack and that with the ground goes to the inputs
> on
> > >> a
> > >> pot and the wiper output goes back in on the tip. I think it expects
> you
> > >> to plug in a different type of pedal, than something that would just
> send
> > >> a
> > >> cv.
> > >>
> > >> I've asked about this here before because I had a problem (this is
> with
> > >> an
> > >> emax II) trying to run the pedal input from a cv sequencer.
> > >>
> > >> Can anyone clarify this? I'll try to look up my old post later, but
> now
> > >> this has me curious about it. I do remember making a "pedal" with a
> pot
> > >> so
> > >> I could just turn a parameter in realtime so I know that part is true.
> > >>
> > >> ________________________________
> > >> From: zrennaya <zrennaya@...>
>
> > >> To: emax@yahoogroups.com
> > >> Sent: Friday, March 2, 2012 7:52 AM
> > >> Subject: [emax] Re: Emax pedal input and control voltages
> > >>
> > >>
> > >>
> > >>
> > >> Thanks jammie..again!
> > >>
> > >> So if I got you correctly, that particular ssm2300 has several
> channels
> > >> (I'm guessing 8), emax uses one for each of the onboard CV sources
> and if
> > >> they all work correctly it's only the pedal input channel that's
> messed
> > >> up
> > >> and it splits its signal to the same output as the data slider for
> > >> example,
> > >> plus the sampling itself is also messed up on that specific channel?
> > >>
> > >> And sample and hold in this case means it's a basic AD converter and
> on
> > >> the analog processing end there's a same basic DA one, right? I mean,
> the
> > >> onboard controls are pretty smooth considering that but do you think
> > >> their
> > >> resolution is good enough for me to use an already D->A controller
> and go
> > >> A->D->A with them again? I'm talking about a higher-rate saw LFO.
> > >>
> > >> Thanks!
> > >>
> > >> --- In emax@yahoogroups.com, "jammie" <jammie.emma@> wrote:
> > >> >
> > >> > ssm octal sample and hold ic is damaged
> > >> >
> > >> > ssm2300 exchange for a smp08 by analog devices its a pin for pin
> > >> replacement and has a better slew rate
> > >> >
> > >> > the pitch wheel the modulation wheel the volume slider and data
> slider
> > >> are cv sources the ssm2300 samples these and send the digital data to
> the
> > >> cpu which then processes the info and sends it to the smm2300 that
> out
> > >> puts
> > >> the digital control data to a cv analog output for controlling the
> filter
> > >> or vca or panning
> > >> >
> > >> > you need to check the manual as i dont have it in front of me but
> > >> > therte
> > >> are several ssm2300 octal sample and hold multiplexer ic
> > >> >
> > >> > you need to check the manual for the 1 that samples the voltages
> from
> > >> the controllers
> > >> > ----- Original Message -----
> > >> > From: zrennaya
> > >> > To: emax@yahoogroups.com
> > >> > Sent: Friday, March 02, 2012 11:48 AM
> > >> > Subject: [emax] Emax pedal input and control voltages
> > >> >
> > >> >
> > >> >
> > >> >
> > >> > Hi everybody!
> > >> >
> > >> > I have another issue with my Emax, I've tried to use a CV signal to
> > >> alter the filter cutoff -since there's only a sinewave internal LFO.
> The
> > >> manual says the pedal input receives standard CV signals but here's
> what
> > >> it
> > >> does for me: even if the pedal input is not assigned to anything in
> > >> preset
> > >> definition, when I send a CV signal, the display jumps around
> different
> > >> submenus, on the main page it jumps around presets and when the
> cursor is
> > >> on some parameter to adjust, it changes the values, so basically it
> does
> > >> the same job as the DATA slider.
> > >> >
> > >> > The other thing is, this is a MIDI controllable CV source, so MIDI
> CC
> > >> values 0->127 means -5V -> +5V control voltage and even if I try to
> > >> recalibrate the pedal input, when the cursor is over a parameter
> value,
> > >> when I turn the MIDI knob, there's no increment between cc values
> 0-51,
> > >> then some weird increment jumps between 52-59, then no increment
> between
> > >> 60-124, then major jump between 124-127.
> > >> > Consequently, when I assign the pedal input to the filter fc, the
> > >> > cutoff
> > >> frequency is jumping around in the same fashion, while the submenus
> jump
> > >> around on the display at the same time.
> > >> > Could anyone please give me some advice, or knows wether I'm doing
> > >> something wrong or it's the emax's fault? Thanks a milion!!
> > >> >
> > >> >
> > >> >
> > >> >
> > >> >
> > >> > [Non-text portions of this message have been removed]
> > >> >
> > >>
> > >> [Non-text portions of this message have been removed]
> > >>
> > >>
> > >>
> > >
> > >
> > > [Non-text portions of this message have been removed]
> > >
> > >
> > >
> > > ------------------------------------
> > >
> > > Emax and Emax II User's Group Website
> > >
> > > http://www.silveriafamily.comYahoo! Groups Links
> > >
> > >
> > >
> >
> >
> >
> >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
>  
>


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