Ensoniq SQ80
- Thread starter mansher
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R-ond
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ff zoeken harry ...boel heefre eentje te koop mp
check
https://www.synthforum.nl/forums/showthread.php?s=&threadid=78615
kunje gelijk zn memory moog checken hadjij toch ook ?
leuke electro trouwens maakje
check
https://www.synthforum.nl/forums/showthread.php?s=&threadid=78615
kunje gelijk zn memory moog checken hadjij toch ook ?
leuke electro trouwens maakje
R-ond
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Origineel geplaatst door mansher
Hoi Ron,
Thanx!
Ik greep als naast die SY2 en nu ook de SQ80 van Boele,ik zou haast beginnen denken dat die beste iets tegen mij heeft...
Mocht je'r nog ééntje tegenkomen....
oja die vondtje music niks ofso toch [was misverstand ...denk!]
sq80 ook leuk model
iets duurder dan de esq-1 tip ok byna t zelfde bakske [heb m net erg tevreden ,..cleane raw sound waves ,..goed filter en lekkere modulatie
sc6
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kwilde altyd eens een ensoniq proberen vondde asr [x] / 10 ofso nog net iets te duur
maar had veel goed gehoord/gelezen over ensoniq niks is minder waar [ook gelijk maar mirage aangeschaft]
ensoniq doet niksmeer nu toch ...?
is samen met emu d8ik in software ....kaarten enso ..
sq80 best zeldzaam ook 2ndhands
watie nou precies meer heeft ???
tov esq 1
de SQ 80 heeft waveforms die de ESQ1 niet heeft,die zouden wel tevoorschijn te toveren zijn via de procudere beschreven op deze page http://www.buchty.net/ensoniq/ bij de rubriek ; Turn your ESQ-1 into a SQ80,er wordt zelf uitgelegd hoe je'r een floppy drive op kunt aansluiten etc...
Maar dan mis je natuurlijk de polyphone aftertouch van de SQ80,en die had ik bijzinder graag gewild en vormt voor mij een belangrijk aspect in het totaal concept van de SQ80.Het ware ook handig geweest om mijn andromeda es met poly AT te kunnen aansturen.Waarom ze daar geen poly AT keyboerd in gezet hebben verwonderd me tot op de dag van vandaag nog steeds...
Maar dan mis je natuurlijk de polyphone aftertouch van de SQ80,en die had ik bijzinder graag gewild en vormt voor mij een belangrijk aspect in het totaal concept van de SQ80.Het ware ook handig geweest om mijn andromeda es met poly AT te kunnen aansturen.Waarom ze daar geen poly AT keyboerd in gezet hebben verwonderd me tot op de dag van vandaag nog steeds...
SCD
Gearlust [on]
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Origineel geplaatst door mansher
Het ware ook handig geweest om mijn andromeda es met poly AT te kunnen aansturen.Waarom ze daar geen poly AT keyboerd in gezet hebben verwonderd me tot op de dag van vandaag nog steeds...
Dat heeft te maken met patenten meen ik. Er is geen enkele fabrikant die het gebruikt. ZONDE, want het is, als het op de juiste manier is geïmplementeerd een killer modulatiebron.
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ik durf te zeggen dat ik erg gematst ben 140.- voor een esq-1 in ok staat ....thncx cuba!
maar ze gaan algauw ri 200 [ nog steeds meer dan waard ....]
ak m zou moeten vergelijk met bv een poly synth met analoog filter zonder knoppen ,...
bv sixtrak/multitrak
bv de jx 8p??
of de matrix 6 [matrix = leuk] kist toch voor de esq raw dik filters kan ook wollige ebn helder klinken ,..een mega bak voor die centen ,..matrix 6 kost bv al gauw zoon 3a350.- ook leuk daarr
niet van maar [die heeft wel aftertouch keys!!!
iig heeft de esq een erg makkelijk interface een knop voor elke lfo/env osc easy dus!! is ook belangrijk asje tig menus door moetmet een slider is tooch ook minder
[kheb t niet eesn over de waves tov andere analoge/polys....]
nee ensoniq maakt lekker spul
- een sq80 dan wat is dat meer waard begrijp dat er wat meer potentie in zit en floppy drive waar zou ije die voor gebruiken patchen laden ,..ofso ?
maar de sq80/esq zit toch weer verwerkt in latere modellen vfx/enso ...
of isdat heeeeeel anders ?
WHOOOOOOOO
wat een goede site
man patches kan ik die inladen ,...aleen via cardridege
SQ80 sound bank dumps (for use with SQ80 Toolkit only!)
2K ESQ (54 Banks)
ESQ cartridge (2 Banks)
ESX cartridge (4 Banks)
ESX Double Brass cartridge (8 Banks)
MT32 Emulation (3 Banks)
PA cartridge (4 Banks)
Transoniq Hacker Patches (10 Banks)
alleen via sq 80 toolkit ?
en dit is helemaal intressantie
Turn your ESQ-1 into a SQ80
* Adjusting the sound...
* Adding DOSRAM and SEQRAM
(this is a must)
* Increasing Waveform Memory
* Adding a Floppy Controller
ik heb iig t boek erby [durfter byna niet in te kijken soo dik ! zhanx man 4 site
maar ze gaan algauw ri 200 [ nog steeds meer dan waard ....]
ak m zou moeten vergelijk met bv een poly synth met analoog filter zonder knoppen ,...
bv sixtrak/multitrak
bv de jx 8p??
of de matrix 6 [matrix = leuk] kist toch voor de esq raw dik filters kan ook wollige ebn helder klinken ,..een mega bak voor die centen ,..matrix 6 kost bv al gauw zoon 3a350.- ook leuk daarr
niet van maar [die heeft wel aftertouch keys!!!
iig heeft de esq een erg makkelijk interface een knop voor elke lfo/env osc easy dus!! is ook belangrijk asje tig menus door moetmet een slider is tooch ook minder
[kheb t niet eesn over de waves tov andere analoge/polys....]
nee ensoniq maakt lekker spul
- een sq80 dan wat is dat meer waard begrijp dat er wat meer potentie in zit en floppy drive waar zou ije die voor gebruiken patchen laden ,..ofso ?
maar de sq80/esq zit toch weer verwerkt in latere modellen vfx/enso ...
of isdat heeeeeel anders ?
WHOOOOOOOO
wat een goede site
man patches kan ik die inladen ,...aleen via cardridege
SQ80 sound bank dumps (for use with SQ80 Toolkit only!)
2K ESQ (54 Banks)
ESQ cartridge (2 Banks)
ESX cartridge (4 Banks)
ESX Double Brass cartridge (8 Banks)
MT32 Emulation (3 Banks)
PA cartridge (4 Banks)
Transoniq Hacker Patches (10 Banks)
alleen via sq 80 toolkit ?
en dit is helemaal intressantie
Turn your ESQ-1 into a SQ80
* Adjusting the sound...
* Adding DOSRAM and SEQRAM
(this is a must)
* Increasing Waveform Memory
* Adding a Floppy Controller
ik heb iig t boek erby [durfter byna niet in te kijken soo dik ! zhanx man 4 site
R-ond
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3378/79
ahahaha
ook ok om te weten wat nou die chip is doet ...ook in veel andere modellen matrix 6 en meer
CEM3378/3379 Voltage Controlled Signal Processors
The CEM3378 and CEM3379 contain general purpose audio signal processing blocks which are
completely separate from each other. These devices are useful in a wide variety of audio and
musical instrument applications.
The CEM3378 includes a two-channel voltage controlled mixer, a wide range four-pole low-pass
voltage controlled filter with voltage controlled resonance, and a high quality voltage controlled
amplifier featuring low noise and low control voltage feedthrough without trimming.
The CEM3379 includes the same filter and VCA as the CEM3378, but instead of an input
mixer, provides a two-channel voltage controlled output pan function.
Since all blocks have separate input, output, and control terminals they many be interconnected
as shown in the block diagrams, or used separately in different parts of a system. With the
exception of the filter frequency, all control voltage inputs range from 0 to +5V and provide
moderately high impedance for minimal system loading; the filter frequency control voltage
ranges from -150mV to +100mV, allowing easy control voltage mixing and all parameters to be
conveniently controlled with a single polarity DAC.
Able to operate over a wide supply range and requiring a bare minimum of external
components, the CEM3378 and CEM3379 offer the designer means to create unique signal
processing configurations at the lowest possible cost.
FEATURES
· Low Cost
· VCF and 4 VCAs on a single 18 pin DIP
· Separate inputs and outputs for each function
· Choice of Balance (337
or Pan (3379)
· Rich Sounding VCF
· Constant Amplitude versus Resonance VCF Design
· Low Noise, Low Distortion VCA
· Very Low Control Voltage Feedthrough without trims
· Operation down to +-5V
CEM3378/79 Electrical Characteristics
PARAMETER MINIMUM TYPICAL MAXIMUM UNIT
INPUT MIXER/OUTPUT VCAs
Gain range for 0-+5V control 0-3.0 0-3.8 0.4.8 mmho
Input signal for 5% THD --- 75 --- mV pp
Attenuation at VBAL=0 or VBAL=5 80 100 120 dB
DC Control voltage feedthrough --- 10 30 uA
Signal Input Bias Current -0.2 -0.6 -2.0 uA
Balance Control Input Bias -1.5 -5 -15 uA
Maximum Output Current +-150 +-200 +-260 uA
Gain Variation (part to part) --- 0.7 2.0 dB
VC FILTER
Input signal for 1% THD --- 360 --- mV PP
Passband Signal Gain Vres=0V 6.8 7.5 8.3
Input Resistance 3.6 4.5 5.6 KOhm
Frequency Control Range 14 --- --- octaves
Frequency Control Voltage -155 --- 110 mV
Frequency Control Scale 17.5 19.0 20.5 mV/octave
Exponential Scale Error --- 0.3 1.0 %
Initial Frequency (Ca-Cc=0.033uf) 650 1000 1650 Hz
Frequency Control Input Bias -0.2 -0.6 -2.0 uA
Resonance Control Range Q = 0dB --- self-osc
Resonance Control Voltage @osc 2.2 2.8 3.4 V
Resonance Control Input Bias -0.2 -0.5 -1.5 uA/V
DC Output Shift over 10 Octaves --- 100 250 mV pp
Output noise --- 90 --- uVrms
Maximum Output Swing 4.5 5.0 5.5 Vpp
Quiescent DC Output Voltage -0.5 0.0 0.5 V
Output Sink Current -0.4 -0.5 -0.6 ma
Output Source Drive Current --- --- 3.0 ma
FINAL VCA
Gain Control Range 90 120 --- dB
Maximum Signal Current Gain 0.80 0.93 1.10
Control Voltage for Max Gain 4.5 5.0 5.5 V
Control Voltage for Min Gain 30 85 140 mV
Control Input Bias Current -0.1 -0.3 -1.0 uA/V
Voltage at Signal Input Node -2.3 -2.1 -1.9 V
Output Voltage Range -0.8 --- Vcc-1 V
Maximum Input Signal Swing -200 --- 200 uA
Output Noise --- --- 2.0 nA rms
THD @ +-200uA Input Swing --- 0.5 1.5 %
DC Output Offset at Min Gain --- --- 1.0 nA
DC Output Offset Range --- +-0.2 +-1.2 uA
GENERAL
Supply Voltage Range +-4.75 +-9 +-12.5 VDC
Supply Current per Chip 5.8 7.3 9.1 ma
POWER SUPPLIES
The maximum supply allowed across either device is 25 volts. Due to internal voltage
regulators, the supplies do not have to be balanced: +5/-12 is allowed, as would be +12/-5. Since
the maximum positive output swing of the filter is 2.9 volts below the positive supply, some loss
in maximum VCF output will occur at +4.75 volt supply. For best performance with low power
dissipation, use +9/-5 or +12/-5 supply voltages.
INPUT MIXER (337 and OUTPUT PAN (3379)
These VCAs are simple 3080 types with the inverting inputs internally connected to ground.
Thus, the external input should be driven from a low impedance (<1K) referenced to ground.
Control feedthrough may be trimmed if desired by applying a +-5mV adjustable voltage to the
input pin. Note that in the 3379, the inputs are common and so there will be a slight mismatch
between sections.
The gains of the two VCAs are complementary, being equal and half of maximum at a control
voltage of 2.5 volts. The control scales a linear between 1.0 and 3.5V, becoming logarithmic
beyond these extremes.
Since the VCA output(s) have a limited negative output voltage compliance (-0.2V), they must
be fed to a virtual ground summing node on an op amp for large output voltage swings.
However, in cases where the output(s) drive another 3080-type VCA or the input of the VCF
section (where the control voltage swing is less than +-200mV), the output current may be
converted to the required voltage simply with a resistor connected from the output pin to
ground.
In the case of driving the VCF input, an external load resistor is not required since there is an
internal 4.5K (nominal) resistor to ground on the VCF input pin. The VCA voltage gain from
input to output is Gm x Rl = 3.8 mmho x 4500 = 17. Thus, the nominal filter input of 360 mvpp
is achieved with a VCA input of only 21 mvpp, allowing a typical THD of <0.1%. If more
distortion can be tolerated, then a better signal-to-noise ratio can be obtained through the VCA
by adding a resistor from the VCA output/VCF input to ground. A value of 1.6K for instance will
lower the gain from 17 to 4.5, requiring a VCA input of 80 mvpp, or a 12dB SNR improvement.
FILTER
The voltage controlled filter (VCF) is the standard musical 4 pole low pass with internal
feedback through a VCA to add resonance or sustained oscillation at the cut-off frequency. A
portion of the input signal is applied to the resonance VCA, so that as the amount of resonance
is increased, the passband gain drops by only 6dB instead of the normal 12dB without this
technique. This choice of a 6dB drop ensures the peak-to-peak output level remains the same
when the output waveform rings from added resonance.
If the VCF input signal comes from a source other than the mixer output, it will most likely
require attenuation down to the nominal 360mv pp level. This is easily accomplished with a
single series resistor to the input pin (Pin. The amount of attenuation is given by:
1 + (Rin/4500)
However, the internal 4500 ohm resistor has a 25% tolerance, so a chip-to-chip +-2.5dB
variation is to be expected. Lower variation can be obtained by adding a shunt resistor to
ground. A 1.3K shunt resistor will reduce the input resistance to 1K and the output variation
caused by the 4.5K will be reduced to +-0.5dB. For best performance, the signal applied to the
filter input should have < 50mv DC component.
The cut-off frequency of the filter (which is defined as the oscillation frequency at maximum
resonance or the -9dB point at no resonance) is determined by the transconductance and
associated capacitance of each of the 4 stages as:
fc = Gm/(2 x pi x C)
Since the transconductance of the last stage is 1/75th of the other 3 stages, the capacitor value is
1/75th of the other capacitors. Best sweep performance is obtained over a transconductance
range of 1umho to 4 mmho. For a desired frequency range of 5Hz to 20KHz, Ca, Cb, and Cc are
chosen to be 33nF and Cd becomes 470pF. Note that the frequency can be swept one octave
above and below these frequencies.
The transconductance is varied in an exponential manner with the control voltage, and is given
in umhos by
Gm = 200exp (Vfreq/VT)
where VT is approximately 28.5mv at 20C and has a temperature coefficient of +3300ppm. Note
that when Vfreq = 0, the transconductance in nominally 200 umho, resulting in a cutoff
frequency of around 1KHz with the capacitors given. The lower frequency of 5Hz is 7.6 octaves
below the zero control voltage. This requires a -150mv signal. The upper limit of 20Khz requires
a 90mv control voltage signal.
In the usual case, the system frequency control voltage must be attenuated with a resistor
divider down to these levels. If the system CV ranges from 0 to a positive value (most likely),
then an additional resistor between the control pin and the negative supply voltage is need to
produce a negative voltage for the lower cutoff frequencies. For best results, the input
impedance to the control pin should be <2K. Although the transconductors themselves have
been internally temperature compensated, the control scale still has a -3300ppm factor due to
TC. Therefore, a +3300ppm temperature compensation resistor is used in the CV attenuation
network.
The VCF output (Pin 1) is a low impedance output capable of driving loads down to 6.8K. If
more drive is required, a resistor Rout may be connected between the output and the negative
supply. The minimum load which may be driven is:
Rload (Kohm) = 2.5/(0.4 + Vee/Rout)
where Rout is in Kohms. The output is not short circuit protected. Therefore, if this pin is
connected to outside of the equipment, a series resistor of 470 ohms in series with the output
pin is needed.
FINAL VCA
The final VCA is a low noise, low control voltage feedthrough design which does not require any
trimming to null. Hence it is well suited for being controlled by fast transition envelopes
without producing “pops” or “clicks”.
The VCA signal input is a current summing input at a voltage of -2.1V, requiring an external
series capacitor and resistor between the input signal voltage and input pin (Pin 13). The
maximum input current should be limited to +-200uA. The value of input resistor is therefore:
Rin = Vin/400uA
The series capacitor is then chosen to give the desired -3dB low frequency corner with the
selected resistor.
Somewhat lower distortion can be obtained with a lower maximum input current of +-50 to +-
100uA at the expense of slightly lower signal-to-noise ratio and larger relative control
feedthrough. Distortion also increases the lower input signal voltage; therefore the input signal
voltage should be kept about 1Vpp.
The control scale is exponential from 0 to approx. 200mv, controlling the current gain from -
100dB to about -20dB. Thereafter the current gain increases in a linear fashion until it reaches
0dB at +5V nominal. This slight rounded knee at the scale bottom allows an envelope to decay
to zero with a natural exponential sound regardless of the small variations in VCA turn-on
threshold.
As this VCA also has limited negative output voltage compliance (-1v max.), it is best to convert
the output current to a voltage with a virtual ground summing op amp. Of course, if the output
voltage needs to be no greater than 2V pp, the current-to-voltage conversion may be
accomplished with a resistor to ground. The maximum voltage gain at +5V control is:
Amax = Rf/(Rin + 1.5K)
The outputs from several VCAs may be summed together by simply connecting the output pins
together before converting to a voltage.
ahahaha
ook ok om te weten wat nou die chip is doet ...ook in veel andere modellen matrix 6 en meer
CEM3378/3379 Voltage Controlled Signal Processors
The CEM3378 and CEM3379 contain general purpose audio signal processing blocks which are
completely separate from each other. These devices are useful in a wide variety of audio and
musical instrument applications.
The CEM3378 includes a two-channel voltage controlled mixer, a wide range four-pole low-pass
voltage controlled filter with voltage controlled resonance, and a high quality voltage controlled
amplifier featuring low noise and low control voltage feedthrough without trimming.
The CEM3379 includes the same filter and VCA as the CEM3378, but instead of an input
mixer, provides a two-channel voltage controlled output pan function.
Since all blocks have separate input, output, and control terminals they many be interconnected
as shown in the block diagrams, or used separately in different parts of a system. With the
exception of the filter frequency, all control voltage inputs range from 0 to +5V and provide
moderately high impedance for minimal system loading; the filter frequency control voltage
ranges from -150mV to +100mV, allowing easy control voltage mixing and all parameters to be
conveniently controlled with a single polarity DAC.
Able to operate over a wide supply range and requiring a bare minimum of external
components, the CEM3378 and CEM3379 offer the designer means to create unique signal
processing configurations at the lowest possible cost.
FEATURES
· Low Cost
· VCF and 4 VCAs on a single 18 pin DIP
· Separate inputs and outputs for each function
· Choice of Balance (337
or Pan (3379)· Rich Sounding VCF
· Constant Amplitude versus Resonance VCF Design
· Low Noise, Low Distortion VCA
· Very Low Control Voltage Feedthrough without trims
· Operation down to +-5V
CEM3378/79 Electrical Characteristics
PARAMETER MINIMUM TYPICAL MAXIMUM UNIT
INPUT MIXER/OUTPUT VCAs
Gain range for 0-+5V control 0-3.0 0-3.8 0.4.8 mmho
Input signal for 5% THD --- 75 --- mV pp
Attenuation at VBAL=0 or VBAL=5 80 100 120 dB
DC Control voltage feedthrough --- 10 30 uA
Signal Input Bias Current -0.2 -0.6 -2.0 uA
Balance Control Input Bias -1.5 -5 -15 uA
Maximum Output Current +-150 +-200 +-260 uA
Gain Variation (part to part) --- 0.7 2.0 dB
VC FILTER
Input signal for 1% THD --- 360 --- mV PP
Passband Signal Gain Vres=0V 6.8 7.5 8.3
Input Resistance 3.6 4.5 5.6 KOhm
Frequency Control Range 14 --- --- octaves
Frequency Control Voltage -155 --- 110 mV
Frequency Control Scale 17.5 19.0 20.5 mV/octave
Exponential Scale Error --- 0.3 1.0 %
Initial Frequency (Ca-Cc=0.033uf) 650 1000 1650 Hz
Frequency Control Input Bias -0.2 -0.6 -2.0 uA
Resonance Control Range Q = 0dB --- self-osc
Resonance Control Voltage @osc 2.2 2.8 3.4 V
Resonance Control Input Bias -0.2 -0.5 -1.5 uA/V
DC Output Shift over 10 Octaves --- 100 250 mV pp
Output noise --- 90 --- uVrms
Maximum Output Swing 4.5 5.0 5.5 Vpp
Quiescent DC Output Voltage -0.5 0.0 0.5 V
Output Sink Current -0.4 -0.5 -0.6 ma
Output Source Drive Current --- --- 3.0 ma
FINAL VCA
Gain Control Range 90 120 --- dB
Maximum Signal Current Gain 0.80 0.93 1.10
Control Voltage for Max Gain 4.5 5.0 5.5 V
Control Voltage for Min Gain 30 85 140 mV
Control Input Bias Current -0.1 -0.3 -1.0 uA/V
Voltage at Signal Input Node -2.3 -2.1 -1.9 V
Output Voltage Range -0.8 --- Vcc-1 V
Maximum Input Signal Swing -200 --- 200 uA
Output Noise --- --- 2.0 nA rms
THD @ +-200uA Input Swing --- 0.5 1.5 %
DC Output Offset at Min Gain --- --- 1.0 nA
DC Output Offset Range --- +-0.2 +-1.2 uA
GENERAL
Supply Voltage Range +-4.75 +-9 +-12.5 VDC
Supply Current per Chip 5.8 7.3 9.1 ma
POWER SUPPLIES
The maximum supply allowed across either device is 25 volts. Due to internal voltage
regulators, the supplies do not have to be balanced: +5/-12 is allowed, as would be +12/-5. Since
the maximum positive output swing of the filter is 2.9 volts below the positive supply, some loss
in maximum VCF output will occur at +4.75 volt supply. For best performance with low power
dissipation, use +9/-5 or +12/-5 supply voltages.
INPUT MIXER (337
and OUTPUT PAN (3379)These VCAs are simple 3080 types with the inverting inputs internally connected to ground.
Thus, the external input should be driven from a low impedance (<1K) referenced to ground.
Control feedthrough may be trimmed if desired by applying a +-5mV adjustable voltage to the
input pin. Note that in the 3379, the inputs are common and so there will be a slight mismatch
between sections.
The gains of the two VCAs are complementary, being equal and half of maximum at a control
voltage of 2.5 volts. The control scales a linear between 1.0 and 3.5V, becoming logarithmic
beyond these extremes.
Since the VCA output(s) have a limited negative output voltage compliance (-0.2V), they must
be fed to a virtual ground summing node on an op amp for large output voltage swings.
However, in cases where the output(s) drive another 3080-type VCA or the input of the VCF
section (where the control voltage swing is less than +-200mV), the output current may be
converted to the required voltage simply with a resistor connected from the output pin to
ground.
In the case of driving the VCF input, an external load resistor is not required since there is an
internal 4.5K (nominal) resistor to ground on the VCF input pin. The VCA voltage gain from
input to output is Gm x Rl = 3.8 mmho x 4500 = 17. Thus, the nominal filter input of 360 mvpp
is achieved with a VCA input of only 21 mvpp, allowing a typical THD of <0.1%. If more
distortion can be tolerated, then a better signal-to-noise ratio can be obtained through the VCA
by adding a resistor from the VCA output/VCF input to ground. A value of 1.6K for instance will
lower the gain from 17 to 4.5, requiring a VCA input of 80 mvpp, or a 12dB SNR improvement.
FILTER
The voltage controlled filter (VCF) is the standard musical 4 pole low pass with internal
feedback through a VCA to add resonance or sustained oscillation at the cut-off frequency. A
portion of the input signal is applied to the resonance VCA, so that as the amount of resonance
is increased, the passband gain drops by only 6dB instead of the normal 12dB without this
technique. This choice of a 6dB drop ensures the peak-to-peak output level remains the same
when the output waveform rings from added resonance.
If the VCF input signal comes from a source other than the mixer output, it will most likely
require attenuation down to the nominal 360mv pp level. This is easily accomplished with a
single series resistor to the input pin (Pin
. The amount of attenuation is given by:1 + (Rin/4500)
However, the internal 4500 ohm resistor has a 25% tolerance, so a chip-to-chip +-2.5dB
variation is to be expected. Lower variation can be obtained by adding a shunt resistor to
ground. A 1.3K shunt resistor will reduce the input resistance to 1K and the output variation
caused by the 4.5K will be reduced to +-0.5dB. For best performance, the signal applied to the
filter input should have < 50mv DC component.
The cut-off frequency of the filter (which is defined as the oscillation frequency at maximum
resonance or the -9dB point at no resonance) is determined by the transconductance and
associated capacitance of each of the 4 stages as:
fc = Gm/(2 x pi x C)
Since the transconductance of the last stage is 1/75th of the other 3 stages, the capacitor value is
1/75th of the other capacitors. Best sweep performance is obtained over a transconductance
range of 1umho to 4 mmho. For a desired frequency range of 5Hz to 20KHz, Ca, Cb, and Cc are
chosen to be 33nF and Cd becomes 470pF. Note that the frequency can be swept one octave
above and below these frequencies.
The transconductance is varied in an exponential manner with the control voltage, and is given
in umhos by
Gm = 200exp (Vfreq/VT)
where VT is approximately 28.5mv at 20C and has a temperature coefficient of +3300ppm. Note
that when Vfreq = 0, the transconductance in nominally 200 umho, resulting in a cutoff
frequency of around 1KHz with the capacitors given. The lower frequency of 5Hz is 7.6 octaves
below the zero control voltage. This requires a -150mv signal. The upper limit of 20Khz requires
a 90mv control voltage signal.
In the usual case, the system frequency control voltage must be attenuated with a resistor
divider down to these levels. If the system CV ranges from 0 to a positive value (most likely),
then an additional resistor between the control pin and the negative supply voltage is need to
produce a negative voltage for the lower cutoff frequencies. For best results, the input
impedance to the control pin should be <2K. Although the transconductors themselves have
been internally temperature compensated, the control scale still has a -3300ppm factor due to
TC. Therefore, a +3300ppm temperature compensation resistor is used in the CV attenuation
network.
The VCF output (Pin 1) is a low impedance output capable of driving loads down to 6.8K. If
more drive is required, a resistor Rout may be connected between the output and the negative
supply. The minimum load which may be driven is:
Rload (Kohm) = 2.5/(0.4 + Vee/Rout)
where Rout is in Kohms. The output is not short circuit protected. Therefore, if this pin is
connected to outside of the equipment, a series resistor of 470 ohms in series with the output
pin is needed.
FINAL VCA
The final VCA is a low noise, low control voltage feedthrough design which does not require any
trimming to null. Hence it is well suited for being controlled by fast transition envelopes
without producing “pops” or “clicks”.
The VCA signal input is a current summing input at a voltage of -2.1V, requiring an external
series capacitor and resistor between the input signal voltage and input pin (Pin 13). The
maximum input current should be limited to +-200uA. The value of input resistor is therefore:
Rin = Vin/400uA
The series capacitor is then chosen to give the desired -3dB low frequency corner with the
selected resistor.
Somewhat lower distortion can be obtained with a lower maximum input current of +-50 to +-
100uA at the expense of slightly lower signal-to-noise ratio and larger relative control
feedthrough. Distortion also increases the lower input signal voltage; therefore the input signal
voltage should be kept about 1Vpp.
The control scale is exponential from 0 to approx. 200mv, controlling the current gain from -
100dB to about -20dB. Thereafter the current gain increases in a linear fashion until it reaches
0dB at +5V nominal. This slight rounded knee at the scale bottom allows an envelope to decay
to zero with a natural exponential sound regardless of the small variations in VCA turn-on
threshold.
As this VCA also has limited negative output voltage compliance (-1v max.), it is best to convert
the output current to a voltage with a virtual ground summing op amp. Of course, if the output
voltage needs to be no greater than 2V pp, the current-to-voltage conversion may be
accomplished with a resistor to ground. The maximum voltage gain at +5V control is:
Amax = Rf/(Rin + 1.5K)
The outputs from several VCAs may be summed together by simply connecting the output pins
together before converting to a voltage.
R-ond
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Origineel geplaatst door VlEen
Krijg zin om je te quoten R-ond, maar dan is deze draad helemaal naar de kl*te :confused:
doemaar niet ...ast over ensoniq gaat ,...ik ga een verzamel draad beginnen denk met links naar ...esq /sq 80 zijn meer mensen die willen hebben en t ...moeten wetenb
eg mega machines [lees ik nu kunne nog veeeel meeeer dan ik d8!]
sq gezocht voor topic starter
hiehaaaaaaaa
Akikaze
Hardware only
De Andromeda met polyfone aftertouch aansturen lukt niet. Ik heb dat geprobeerd met o.a. de SQ-80. De handleiding vermeldt het wel; ik voelde me wel een beetje belazerd; dacht bijna alle CS-80 functionaliteit te hebben.Origineel geplaatst door mansher
de SQ 80 heeft waveforms die de ESQ1 niet heeft,die zouden wel tevoorschijn te toveren zijn via de procudere beschreven op deze page http://www.buchty.net/ensoniq/ bij de rubriek ; Turn your ESQ-1 into a SQ80,er wordt zelf uitgelegd hoe je'r een floppy drive op kunt aansluiten etc...
Maar dan mis je natuurlijk de polyphone aftertouch van de SQ80,en die had ik bijzinder graag gewild en vormt voor mij een belangrijk aspect in het totaal concept van de SQ80.Het ware ook handig geweest om mijn andromeda es met poly AT te kunnen aansturen.Waarom ze daar geen poly AT keyboerd in gezet hebben verwondert me tot op de dag van vandaag nog steeds...
R-ond
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- 11 januari 2003
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ik vindt de andromeda toch ook erg fatt ,..soo veel opties en multitimbre en analoog en 16 voices ...aller belangrijks veel parameter / knoppen
zijn der eiegnlijk tegenhangers die t zelfde bieden ,...voor een redelijk prijs
uhh memphisto was ook zoiets nooit meer iets van gehoord ?
een matrix 12 / sun syn is denk ook wel een soort van geen 16 voices ?
andromeda stat qa value 4 money best hoog by int vaandel ,..nog net onbetaalbaar poir moi
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