A-101-3 Modular Vactrol Phase Filter |
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Klangbeispiele unseres Kunden Andreas
Krebs / sound examples by our customer Andreas Krebs: http://blog.andreaskrebs.de/2010/06/27/doepfer-a-101-3-modular-12-stage-vactrol-phaser-example/ |
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Deutscher Text | English Words | ||
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Das Modul A-101-3 ist ein 12-stufiger
Phase-Shifter, der mit sog. Vactrols als phasenschiebende Elementen arbeitet.
Vactrols sind bekannt für Ihren weichen und verzerrungsarmen Klang. Falls Sie
mehr über Vactrols wissen wollen, so finden Sie detaillierte Informationen auf
der Seite Vactrol Grundlagen. |
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A-101-3 Blockschaltbild |
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Am Ende der Seite finden Sie eine Reihe von Frequenzgang-Kurven, die die zahlreichen Möglichkeiten des Moduls deutlich machen: Die erste Gruppe der 12 Kurven zeigen den Frequenzgang wenn die Stufen 1...12 als Eingang für den Ausgangsmixer verwendet werden (keine Rückkopplungen und keine sonstigen Patches). Dies ist die Standard-Phaserschaltung mit unterschiedlicher Anzahl von Phaserstufen. Die Bilder zeigen, dass die Zahl der Kerben des entstehenden Kammfilters von der Zahl der verwendeten Phaserstufen abhängt. Die Kerben bewegen sich durch das Audiospektrum, wenn die Phasenverschiebung geändert wird (manuell oder mit Hilfe einer externen Steuerspannung, beim Standard-Phaser wird meist der Dreieck- oder Sinusausgang eines LFOs zur Modulation verwendet). Die Zahl der Kerben berechnet sich nach folgendem Schema: Zahl der Kerben = Ganzzahl (Zahl der Phaserstufen/2). Eine ungerade Zahl von Stufen führt zu einem asymmetrischen Verhalten am oberen und unteren Ende des Spektrums (oben: Hochpassverhalten, unten: Durchlass). Eine gerade Zahl von Stufen führt zu einem identischen Verhalten am oberen und unteren Ende des Spektrums (oben und unten Durchlass). Verwendet man nur Stufe 1 erhält man einen Hochpass, Stufe 2 ergibt ein Notch-Filter. Die zweite Gruppe zeigt das Frequenzverhalten, wenn ein Inverter zwischen der Phaserstufe und dem Mixer eingefügt wird (einer der Polarizer kann z.B. hierfür verwendet werden). Das Ergebnis ist ein invertierter Frequenzgang gegenüber der ersten Gruppe, z.B. Tiefpass für Stufe 1, Bandpass für Stufe 2 usw. Der Frequenzgang ergibt sich aus dem betreffenden Bild der ersten Gruppe jeweils durch Spiegelung an der horizontalen Achse. Zusätzliche Rückkopplung färbt den Klang (ähnlich der Resonanz/Emphasis-Funktion bei normalen Filtern). Die dritte Gruppe zeigt Frequenzgänge mit einer Rückkopplungsschleife. Für die Rückkopplung auf Stufe 1 wird immer die gleiche Stufe verwendet, die auch als Ausgangsstufe zum Einsatz kommt (Beispiel: wird Stufe 11 als Ausgang verwendet, so erfolgt wird die Rückkopplung von Stufe 11 auf Stufe 1). Es ist jedoch nicht zwingend, die gleiche Stufe für die Rückkopplung zu verwenden, die als Ausgangsstufe benutzt wird. Die Gruppen 4, 5 and 6 zeigen das Verhalten mit verschiedenen Rückkopplungsschleifen (feedback loops). In Gruppe 4 wird beispielsweise immer der Ausgang 12 als Audio-Ausgang verwendet, die Rückkopplung erfolgt jedoch von den Stufen 12, 11, 10, 9 usw. Gruppe 5 ist ähnlich, jedoch wird Stufe 6 als Audio-Ausgang verwendet. In Gruppe 6 ist die Ausgangsstufe der veränderliche Parameter, die Rückkopplung erfolgt immer von Stufe 8 zu Stufe 1 für alle Filter. Als Ergebnis aus all diesen Kurven lässt sich folgendes festhalten:
Durch das offene Konzept des Moduls sind unterschiedliche Zahlen von Kerben und Peaks möglich, indem man den entsprechenden Patch für die gewünschte Anzahl von Kerben und Peaks verwendet ! Last but not least ermöglicht die offene Struktur des Moduls auch mehrfache Rückkopplungsschleifen (z.B .Stufe 8 auf 3 und Stufe 6 auf 1 gleichzeitig) und sogar "Vorwärts-Schleifen" (z.B. von Stufe 5 auf 9). In Kombination mit den beiden Polarizern kann die Polarität für die Rückkopplung normal oder invertiert gewählt werden, was zu weiteren Effekten und neuen Filterkennlinien führt. Einige Beispiele für mehrfache und Vorwärts-Schleifen finden Sie in der letzten Gruppe der Frequenzgangkurven. Beachten Sie, dass für einige Beispiele eine Veränderung der Rückkopplungsstärke auch zum "Wandern" der Peaks relativ zu den Kerben führt ! Mit Hilfe von VCAs (A-130, A-131, A-132) oder des spannungsgesteuerten Polarizers A-133 können die Rückkopplungen natürlich auch spannungsgesteuert werden. Die deutsche Bedienungsanleitung ist als PDF-Datei auf unserer Website verfügbar: A1013_Anl.pdf. |
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Module A-101-3 is a 12 stage phase shifter with vactrols as phase
shifting elements. Vactrols are known for their smooth sound behaviour. For more
general details about vactrols please look at the Vactrol
Basics page. For a better understanding of the outstanding features a table with frequency response graphs is added at the end of this document. The first 12 frequency response curves show the behaviour of the module when stages 1...12 are used as outputs for the final mixer (no feedback, no additional patching). This is the standard phaser application with a different number of phase shift stages. The frequency response curves of the higher stages show the typical comb filters of a phaser. The notches move through the audio spectrum as the manual phase shift control is operated or a control voltage is applied (for a standard phase shifter this is normally the triangle or sine wave from a LFO). The number of notches increases with the number of stages: number of notches = integer of number of stages/2. Odd stage numbers lead to different behaviours in the higher and lower frequencies (low end: high pass behaviour, high end: passage). Even stage numbers show the same response in the higher and lower frequencies (passage for both). Stage 1 is nothing but a high pass filter, stage 2 is the standard notch filter. The second 12 frequency response curves show the behaviour when an inverter is inserted between the stage output in question and the final mixer (one of the polarizers can be used for this job). The result is the inverse frequency response compared to the output without inverter: e.g. low pass for stage 1, band pass for stage 2. The resulting frequency response curve is simply obtained by vertical mirroring the first 12 curves. Additional feedback colors the sound. The third 12 frequency response curves show the behaviour of the filters with one feedback loop. Feedback comes from the stage used as output back to stage 1 (e.g. if stage 11 is used, feedback from stage 11 to stage 1). But it is not imperative to use the same stage for feedback and audio output. Groups 4, 5 and 6 of frequency response curves show the behaviour with different feedback loops. In group 4 the same output 12 is used for all graphs but but the feedback goes from stage 12, 11, 10, 9 ... and so on back to stage 1. Group 5 is nearly the same but output 6 is used for all graphs. In group 6 the output stage is the varying parameter and the feedback goes from stage 8 to 1 for all filters. This is the result from all the response curves:
Different numbers of notches and peaks are possible by using the corresponding patch for output in use and feedback loop ! Last but not least the open structure of the module allows multiple feedback loops (e.g. stage 8 to 3 and stage 6 to 1 simultaneously) and even "forward" loops (e.g. from stage 5 to stage 9). In combination with polarizers additionally the feedback or the output polarity can be normal or inverted. This leads to a multitude of possible filter types. Some examples for multiple and forward loops are shown in the last section of the response curves. Pay attention that for some examples e.g. varying the feedback leads to "moving" peaks. By means of VCAs (A-130, A-131, A-132) or the voltage controlled polarizer A-133 the feedbacks can be voltage controlled. For more detailed information please look at the English user's manual A1013_man.pdf |
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A-101-3 Sketch |
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Breite/Width:
30TE / 30HP / 152.0 mm Tiefe/Depth: 65 mm (gemessen ab der Rückseite der Frontplatte / measured from the rear side of the front panel) Strombedarf/Current: +50mA (+12V) / -50mA (-12V) |
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nicht mehr lieferbar / no longer available |
Frequency response curves Frequency range is 20Hz ... 20kHz for all graphs |
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1. Output stages 12...1
mixed 50:50 with input signal (no feedback, no additional patches) The first 12 frequency response curves show the behaviour of module when stages 1...12 are used as outputs for the final mixer (no feedback, no additional patching). This is the standard phaser application with a different number of phase shift stages. The frequency response curves of the higher stages show the typical comb filters of a phaser. The notches move through the audio spectrum as the manual phase shift control is operated or a control voltage is applied (for a standard phase shifter this is the triangle or sine wave from a LFO). The number of notches increase with the stage number: number of notches = integer of number of stages/2. Odd stage numbers lead to different behaviours in the higher and lower frequencies (low end: high pass behaviour, high end: passage). Even stage numbers show the same response in the higher and lower frequencies (passage for both). Stage 1 is nothing but a high pass filter, stage 2 a notch. |
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Stage 12 | Stage 11 | Stage 10 | Stage 9 | Stage 8 | Stage 7 |
Stage 6 | Stage 5 | Stage 4 | Stage 3 | Stage 2 (= notch) | Stage 1 (= high pass) |
2. Inverted
output stages 12...1 mixed 50:50 with input signal (no feedback, no
additional patches) The second 12 frequency response curves show the behaviour if an inverter is inserted between the stage output in question and the final mixer (one of the polarizers can be used for this). The result is the inverse frequency response compared to the output without inverter: e.g. low pass for stage 1, band pass for stage 2. The resulting frequency response curve is simply obtained by vertical mirroring the first 12 curves. |
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Stage 12 | Stage 11 | Stage 10 | Stage 9 | Stage 8 | Stage 7 |
Stage 6 | Stage 5 | Stage 4 (the famous fast food filter known from A-107) |
Stage 3 | Stage 2 (= band pass) | Stage 1 (= low pass) |
3. Output stages 12...1
mixed 50:50 with input signal with increasing feedback (the
output stage is used for feedback to stage 1 too) blue = min. feedback, red = medium feedback, green = high feedback Additional feedback colors the sound. The third 12 frequency response curves show the behaviour of the filters with one feedback loop. Feedback comes from the stage used as output back to stage 1 (e.g. if stage 11 is used, feedback from stage 11 to stage 1). |
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Stage 12, feedback from 12 to 1 | Stage 11, feedback from 11 to 1 | Stage 10, feedback from 10 to 1 | Stage 9, feedback from 9 to 1 | Stage 8, feedback from 8 to 1 | Stage 7, feedback from 7 to 1 |
Stage 6, feedback from 6 to 1 | Stage 5, feedback from 5 to 1 | Stage 4, feedback from 4 to 1 | Stage 3, feedback from 3 to 1 | Stage 2 , feedback from 2 to 1 | Stage 1, feedback from 1 (out) to 1 (in) |
4. Output stage 12 mixed
50:50 with input signal with increasing feedback (feedback from stage
12...1 to 1) blue = min. feedback, red = medium feedback, green = high feedback But it is not imperative to use the same stage for feedback and audio output. The fourth and fifth group of frequency response show the behaviour with different feedback loops. Always the same output is used (output 12 for group 4, resp. output 6 for group 5) but the feedback goes from stage 12, 11, 10, 9 ... and so on back to stage 1. |
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Stage 12, feedback from 12 to 1 | Stage 12, feedback from 11 to 1 | Stage 12, feedback from 10 to 1 | Stage 12, feedback from 9 to 1 | Stage 12, feedback from 8 to 1 | Stage 12, feedback from 7 to 1 |
Stage 12, feedback from 6 to 1 | Stage 12, feedback from 5 to 1 | Stage 12, feedback from 4 to 1 | Stage 12, feedback from 3 to 1 | Stage 12 , feedback from 2 to 1 | Stage 12, feedback from 1 (out) to 1 (in) |
5. Output stage 6 mixed
50:50 with input signal with increasing feedback (feedback from stage
12...1 to stage 1 for all filters) blue = min. feedback, red = medium feedback, green = high feedback |
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Stage 6, feedback from 12 to 1 | Stage 12, feedback from 11 to 1 | Stage 12, feedback from 10 to 1 | Stage 12, feedback from 9 to 1 | Stage 12, feedback from 8 to 1 | Stage 12, feedback from 7 to 1 |
Stage 12, feedback from 6 to 1 | Stage 12, feedback from 5 to 1 | Stage 12, feedback from 4 to 1 | Stage 12, feedback from 3 to 1 | Stage 12 , feedback from 2 to 1 | Stage 12, feedback from 1 (out) to 1 (in) |
6. Output stages 12...1
mixed 50:50 with input signal with increasing feedback (feedback
from stage 8 to stage 1 for all filters) blue = min. feedback, red = medium feedback, green = high feedback |
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Stage 12, feedback from 8 to 1 | Stage 11, feedback from 8 to 1 | Stage 10, feedback from 8 to 1 | Stage 9, feedback from 8 to 1 | Stage 8, feedback from 8 to 1 | Stage 7, feedback from 8 to 1 |
Stage 6, feedback from 8 to 1 | Stage 5, feedback from 8 to 1 | Stage 4, feedback from 8 to 1 | Stage 3, feedback from 8 to 1 | Stage 2, feedback from 8 to 1 | Stage 1, feedback from 8 to 1 |
7. Some Examples with two
feedback loops blue = min. feedback, red = medium feedback, green = high feedback Last but not least the open structure of the module allows multiple feedback loops (e.g. stage 8 to 3 and stage 6 to 1) and even "forward" loops (e.g. from stage 5 to stage 9). In combination with polarizers additionally the feedback can be normal or inverted. This leads to a multitude of possible filter types. Some examples for multiple and forward loops are shown in the last section of the response curves. |
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Output: stage 10 feedback 1: 8 to 3 feedback 2: 6 to 1 Main peak moves from middle resonance (red) to high resonance (green) to new position |
Output: stage 10 (inverted) feedback 1: 6 to 1 feedback 2: 12 to 10 |
Output: stage 10 feedback 1: 6 to 1 feedback 2: 12 to 10 (inverted) |
Output: stage 10 feedback 1: 6 to 1 feedback 2: 12 to 10 |
Output: stage 10 feedback 1: 4 to 1 feedback 2: 10 to 1 (inverted) |
Output: stage 10 feedback 1: 2 to 1 feedback 2: 10 to 4 (inverted) |
Output: stage 10 feedback 1: 2 to 1 feedback 2: 10 to 3 |
Output: stage 6 feedback 1:9 to 1 feedback 2: 4 to 9 |
Output: stage 6 (inverted) feedback 1: 9 to 1 feedback 2: 4 to 9 |
Output: stage 6 feedback 1: 9 to 1 (inverted) feedback 2: 5 to 9 (inverted) |
Output: stage 6 (inverted) feedback 1: 9 to 1 (inverted) feedback 2: 5 to 9 (inverted) |
Output: stage 6 (inverted) feedback 1: 5 to 1 feedback 2: 9 to 1 |
Output: stage 5 feedback 1: 8 to 1 (inverted) feedback 2: 12 to 6 |
Output: stage 1 (inverted) feedback 1: 8 to 1 (inverted) feedback 2: 12 to 6 (inverted) |
Output: stage feedback 1: feedback 2: |
Output: stage feedback 1: feedback 2: |
Output: stage feedback 1: feedback 2: |
Output: stage feedback 1: feedback 2: |