Oakley SRE330 Скачать руководство пользователя страница 7

In this mode there are four LFOs but they are not simply connected so that one LFO controls 
its own BBD. This should work well but in practice it doesn't give the sound of the classic 
Japanese string machines and effects units that we want to hear. So the SRE330 Multi Mode 
does something much more complicated and, in doing so, can mimic most of the well known 
ensembles units of the past.

STEREO Mode

This is the simplest of the SRE330's three multi modes. Only two BBD lines are used in this 
mode, one for the left hand channel and one for the right. Each BBD produces a similar delay 
when not modulated so that the sound from both left and right is more or less the same. Two 
LFOs, one whose output is a triangle wave, the other, whose output is a sine wave, are used 
as modulation sources. The rate and depth of each LFO is controllable from the front panel 
controls. Both BBDs are modulated by the sum of both LFOs. That is, both LFOs control 
both BBDs together. However, there is one important difference between the modulating 
signals that are sent to each BBD. The BBD that affects the right hand side operates inversely 
to the left hand one. So that when the delay of the left hand BBD is increasing, the right hand 
one is decreasing.

When listened to dry the overall effect is like an odd form of panning and vibrato at the same 
time. But when the balance pot is turned to around 50% a chorus sound is heard.

DUAL Mode

This mode is similar to the stereo mode but features four LFOs and not just two. Instead of 
the right hand BBD being modulated by the inverse of the same LFOs that control the left 
hand side, this time the right hand BBD gets its own pair of triangle and sine wave LFOs. 
However, these LFOs are not completely independent of the left hand side ones. The rate and 
frequency controls are shared with the left hand LFOs. Therefore the right hand side LFOs 
will track the frequency and amplitude of the left hand side LFOs. The only difference between
the two sides are that the right hand side LFOs always run 20% faster than the left hand side. 
This keeps things relatively stable across the stereo panorama, yet, because of the free running
nature of all four LFOs, things are different enough between the channels to give a wide 
ensemble sound.

QUAD Ensemble Mode

The RS or VP ensemble mode. The third mode is the most complex. The basic behaviour is 
the same as the stereo mode, but the quad mode adds an extra BBD circuit to each stereo 
channel. This additional BBD is only controlled by the triangle LFO and not the sine wave 
LFO. However, it responds inversely to the other BBD on its channel. So as the other BBD is 
increasing in delay, the extra one is decreasing. And because it doesn't respond to the sine 
wave LFO, the output of the BBD can be very different to the other BBD on the same 
channel. This creates a rich rolling sound. The classic RS or VP string sound involves only the 
effected sound, ie. 100% wet. The triangle wave LFOs being set to fairly slow (one cycle 
around 5 seconds) but deep modulations. And then with a much smaller amount of faster 
(around 5Hz) sine wave modulation added.

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Содержание SRE330

Страница 1: ...Oakley Sound Systems Stereo Ensemble SRE330 User Manual V2 4 Tony Allgood Oakley Sound Systems CARLISLE United Kingdom ...

Страница 2: ... the components needed to populate the board please visit the main project webpage at http www oakleysound com sre330 htm For general information regarding where to get parts and suggested part numbers please see our useful Parts Guide at the project webpage or http www oakleysound com parts pdf For general information on how to build our modules including circuit board population mounting front p...

Страница 3: ...nally from Europe such as the Solina and Logan String Melody Three BBDs are used in this mode and their delay times are controlled by two three phase fixed frequency sine wave oscillators One of the oscillators the chorus runs very slowly And the other the vibrato runs a little faster However unlike the majority of classic string machines the modulation depths of each oscillator can be controlled ...

Страница 4: ...ill therefore track each other but one is set to always run 20 slower than the other The unit is built into a 1U high full width 19 rack and uses no obsolete parts The input and output sockets are high quality Switchcraft 112APCX devices A relay controlled muting circuit is employed to reduce thumps on the audio outputs when the power supply is switched on and off The unit is powered from a Yamaha...

Страница 5: ...e signal after it has been compressed so the SRE330 s meter will behave slightly differently to normal LED meters such as that found on your audio mixer Any compressor takes a certain time to react to the input signal so very fast transient signals will cause the higher signal LEDs to light even when the apparent volume is quite low Since the signal meter monitors the signal going into the BBDs it...

Страница 6: ...s and set both pan pots to central Each BBD channel produces a delay This delay is altered in real time by two fixed frequency oscillators producing sine waves One oscillator runs slowly and the other much faster The amount of modulation for all three BBD channels is adjusted by the two modulation depth controls on the front panel Each BBD channel is modulated by the same two oscillators but each ...

Страница 7: ...mode but features four LFOs and not just two Instead of the right hand BBD being modulated by the inverse of the same LFOs that control the left hand side this time the right hand BBD gets its own pair of triangle and sine wave LFOs However these LFOs are not completely independent of the left hand side ones The rate and frequency controls are shared with the left hand LFOs Therefore the right han...

Страница 8: ... at its upper and lower limits In 3 PHASE mode this controls the depth of the slow chorus oscillator The waveform used is a sine wave at around 0 6Hz SINE RATE For use with MULTI mode only Controls the rate of the sine wave LFOs A sine wave is similar to the triangle wave but the rises and falls in output voltage are more gentle The waveform is more akin to natural resonances slowing down before i...

Страница 9: ...o jack plugs can be used without detriment to the SRE330 It should work well with signal levels direct from a mixer line level synthesisers and modular synthesisers The input impedance is too low to work direct from guitars unless they are fitted with internal pre amplifiers The SRE330 s stereo inputs can be used with mono sources Simply connect the jack plug to the right hand input socket and the...

Страница 10: ...sets the delay time of BBD line number 3 Measure the signal at pin 6 of U43 Adjust CLK3 so that the frequency of the square wave is approximately 75kHz CLK4 This sets the delay time of BBD line number 4 Measure the signal at pin 6 of U51 Adjust CLK4 so that the frequency of the square wave is approximately 75kHz OFF1 OFF2 OFF3 OFF4 These adjust the bias point of the respective BBD line s input sig...

Страница 11: ...eform amplitude seen on the scope trace is minimised Set incorrectly you ll see a kind of spiky square wave Set correctly the trace will reduce to just a series of spikes Do this for all four BBD lines T_FRQ This sets the frequency range of the triangle LFOs Set TYPE to MULTI and the triangle rate pot to its maximum value Set your scope s time base to 5mS per division and the scaling to 2V per div...

Страница 12: ...nd the vibrato depth pot to its maximum Set your scope s time base to 25mS per division and the scaling to 2V per division Then monitor the voltage on pin 1 of U26 and adjust FAST until you get a 12V peak to peak signal The frequency should be around 6Hz SLOW This sets the frequency of the chorus oscillator in three phase mode Set TYPE to 3 PHASE and the chorus depth pot to its maximum Set your sc...

Страница 13: ...s the Oakley Sound Forum at Muffwiggler com If you have a comment about this user manual or have a found a mistake in it then please do let me know either via e mail or the forum Tony Allgood at Oakley Sound Cumbria UK October 2017 updated September 2020 No part of this document may be copied by whatever means without my permission 13 ...

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