INTRODUCTION
Congratulations on your purchase of the THETA PRO DSP™. The THETA PRO DSP™ was designed to provide the ultimate sonic performance possible in a Guitar DSP based processor; all controlled on the floor, with simplicity of use and programmability. The THETA PRO DSP™ is based on state of the art Digital and Analog circuit design and technology and features ISP Technologies proprietary algorithms for all THETA PRO DSP™ functions. The THETA PRO DSP™ also features the patented Decimator noise reduction system for the highest level of noise reduction and transparency available. Also included on board is a SONG mode allowing the guitarist to arrange presets into 124 songs with 4 preset patches per SONG. Please read this manual carefully for a through explanation of the THETA PRO DSP™ and its functions.
IMPORTANT SAFTEY INSTRUCTIONS
Please read the following very carefully before operating this unit
Read ALL instructions carefully before using this unit. Keep these instructions for future reference. Heed all warnings and follow all instructions.
Do not use this unit near water, in the rain, or where there is moisture. If this warning is ignored a serious electrical shock or death may occur.
Do not attempt to service this unit. No user serviceable parts inside. Refer servicing to qualified, ISP approved personnel. Servicing is required when the unit is damaged in any way, such as power adaptor is damaged, liquid has been spilled into the unit, the unit has been exposed to rain or moisture, does not operate normally, or has been dropped.
Care should be taken to avoid spilling any foreign objects or liquid into this unit. Avoid exposure of this equipment to dripping or splashing and ensure that no objects filled with liquid, such as vases, are placed on the equipment.
Only use accessories or attachments that are specified by the manufacturer.
Failure to follow these instructions may void the warranty.
NO USER SERVICABLE PARTS INSIDE. REFER SERVICING TO
QUALIFIED ISP TECHNOLOGIES SERVICE PERSONNEL.
The lightning bolt triangle is used to alert the user to the risk of electric shock. The exclamation point triangle is used to alert the user to important operating or
maintenance instructions.
POWER REQUIREMENTS
This unit requires the connection of the external AC Power Adaptor to a 120 volt AC outlet. Do not attempt to connect this unit to any power source other than the one supplied with the THETA PRO DSP. The THETA PRO DSP will typically draw on the order of 1.5 amps of current from the AC power adaptor when in use.
Quick Start
Refer to the Figures shown for the hardware drawings which show the locations of the switches, knobs, and jacks when reading the following, or even better, just look at your unit.
1.Connect the guitar to the IN jack, connect the STAGE OUT jack(s) to a power amp such as the ISP Stealth which is connected to a guitar speaker cabinet, OR connect the DIRECT OUT jacks to the input of a mixer, OR connect the PHONES jack to headphones or earbuds (or connect all three). With a mono system, the output(s) can be set to mono in the global parameters later. The STAGE OUT jacks can be connected to a conventional guitar amplifier, but this will not yield optimum results, since most guitar amps will further shape and distort the sound.
2.Connect the supplied 9V AC power adaptor to wall power, then to the POWER input on the Theta Pro. The unit will power up and recall Preset 1. Pressing the RECALL 1 switch will display the Preset 1 title.
3.With the Preset title displayed, adjust the INPUT LEVEL control on the back panel so that the LEVEL 0 LED (red) just flashes when playing hard, then back off the INPUT LEVEL control slightly so that the 0 LED does not light. Short, infrequent flashes of the red 0 LED are generally not audible. Adjust the STAGE OUT LEVEL or PHONES LEVEL controls to taste. The DIRECT OUT levels can be controlled by the global DIRECT TRIM parameter which affects all presets, and by the OUTPUT LEVEL parameter within each preset, which affects all outputs, but is the level specific to each preset. Note that the LEVEL LEDs only display the raw input level when the preset or song titles are displayed (FUNCTION turned fully counterclockwise). If any other parameters are displayed, the LEVEL LEDs will display the maximum of the 4 output DAC (Digital to Analog Converter) levels.
4.Play!
5.Presets can be selected by pressing the PRESET down or up switches, then the RECALL 1 switch. Holding the PRESET down or up switches will result in progressively faster scrolling through the preset titles. The RECALL 2 switch will immediately increment one preset, and the RECALL 3 switch will immediately decrement one preset. These can be used to step through the presets to try them out. The RECALL 4 switch will jump back to the last previously recalled preset, easy to remember since it is the last switch on the
right. If the preset title is displayed (if FUNCTION is set fully counterclockwise), the VALUE knob can be turned to scroll through the preset titles. Pressing the RECALL 1 switch will then recall the selected preset.
6.BOOST, PHASER, TREMOLO, CHORUS, FLANGER, DELAY, and REVERB can be turned on or off by the top row of switches, depending on the settings within each preset.
7.Pressing the SECOND switch allows access to the WAH on/off, STORE, and SONG Mode, as well as TAP functions to set the modulation rates and DELAY time. The FUNCTION knob selects the function such as Preamp, EQ, etc. The PARAM knob selects the parameter within the function, and the VALUE knob adjusts the value.
8.Changing a value will light the red STORE LED. To store the new value for later recall, press the 2nd switch, followed by the STORE switch. Note that the THETA PRO DSP ships with the Preset 1-100 and Preset 101-200 LOCK set to ON, so storing to those presets will display a FAIL message. Storing to presets 201-224 is always allowed. See the section on the Global Parameters for more information on how turn off the Locks.
9.To copy a preset to a different location, first recall the preset. Then scroll to the desired new location by using the PRESET down or up switches, or the
VALUE knob (if FUNCTION is set fully counterclockwise). Note that the preset titles will flash, meaning the preset is not fully recalled. Then press 2nd, STORE to store the last recalled preset into the new location. The original contents of this location will be overwritten, so be careful. The unit ships with 100 unique presets written in locations 1 to 100, then repeated again in locations 101 to 200, we recommend that one of the two banks be left locked to prevent inadvertently writing over the original presets, at least until the storage space is needed for new original presets.
10.Read the rest of the manual, it contains much valuable information to get the most from your Theta Pro DSP!
DETAILED OPERATION:
Refer to Figures above for the hardware drawings which show the locations of the switches, knobs, and jacks when reading the following. Refer to Figure 2 for the signal flow diagram which shows the flow of the signal through the unit from the input to the outputs. The following text explains the operation of the unit organized by the software functions and parameters, but it also incorporates explanations of the hardware functions where they are interrelated to the software. This fusion of both domains together helps to simplify the understanding of the unit, since everything about a single concept is contained together. Also, many important operational details are contained in the Quick Start section, so reading and understanding that section is essential.
PRESET MODE:
This is the default mode when the unit is first turned on. It allows direct recall of presets by name, adjustment and programming of presets, mapping of switches and the expression pedal, MIDI Dump and Load, and setting of Global parameters. The other mode of the unit is SONG MODE, which will be described later.
Functions and Parameters:
Note that the titles of the functions do not always appear on the display, but most of them are contained within the first parameter of that function. The following list of functions are accessed in order by turning the FUNCTION knob clockwise. The parameters are then accessed by turning the PARAM knob. The values displayed are changed by turning the VALUE knob.
A)Mixer Function
1.OUTPUT LEVEL (OFF to +10 dB): Controls the output level feeding all outputs from the unit. This is to allow the presets to be set to nominally equal levels given different gains, compression, EQ, and effects. It also allows adjustment to prevent clipping of the 4 channel output DAC. When the Function is turned to display this or any parameter other than the titles, the LEVEL leds will display the maximum output level of the 4 DAC channels. The OUTPUT LEVEL can then be adjusted to prevent clipping of the DAC by keeping the red 0 dB LED from lighting.
2.DIRECT PAN (0 to 100): Pans the direct signal (the signal before the stereo effects) from Left (0) to Right (100). The primary use for this is to have the direct sent to one channel and the delay sent to the other.
3.BOOST (OFF or ON): When ON, boosts the level of the signal after the Preamp.
4.BOOST LEVEL (0 to 10 dB): Adjusts the amount of BOOST. Note that if the preset already has a hot level, too much boost can clip the output DACs.
B)PREAMP Function
1.PREAMP (CLEAN or DISTORT): In CLEAN, the distortion part of the preamp is bypassed, so the DIST TYPE, GAIN, and SAG parameters have no effect, and it is not possible to get clipping within the preamp section, due to floating point processing. If you are still hearing distortion, it is probably due to the input ADC or output DACs being overdriven, or your guitar, amp, mixer, speakers, headphones, or ears. In DISTORT, the distortion part of the preamp is enabled, so all the parameters become active.
2.DIST TYPE (THETA or VINTAGE): THETA type applies an EQ curve before the clipper stage that matches that of the ISP THETA pedal. This is in addition to the settings of the PRE EQ controls. VINTAGE removes this curve, so that the only pre-distort EQ is what has been set on the PRE EQ controls. Real vintage amps do not have much pre-clip EQ, but sound less desirable at high gain settings.
3.GAIN (1 to 90 dB): Dials up the gain before the clipper stage. Additionally, there is gain available in the Pre EQ and THETA type distortion, so that the total amount of gain applied to the signal can exceed 120 dB! As a point of reference, a typical amp head has a gain of about 60 dB with the knobs set to maximum. If the GAIN is set above 60 dB, the compressor will be disabled, even if the PREAMP is set to CLEAN. To re-enable the compressor, the GAIN must be lowered to 60 or less, then the COMPRESSOR parameter can be turned from OFF to ON.
4.SAG (0 to 100): Emulates the sag of the supply voltage rails in an amp. Higher values result in more sag. As you play harder, the rails sag down resulting in more clipping of the signal. Play softer and the rails move higher, resulting in a cleaner sound. This is most effective with moderate levels of GAIN.
5.OUTPUT LEVEL (OFF to +10 dB): This is the same parameter as in the mixer function. It is just repeated here for convenience because as preamp parameters are changed, it is typical that the output level will need to be readjusted.
6.COMPRESSOR (OFF or ON): Turns on the compressor, which is positioned before the clipper stage. Compression is useful for making clean or low gain settings sound louder, as it reduces the level of loud passages and increases the level of soft passages. The downside is the more compression used via lowering the threshold, the more noise is added to the signal. See the GAIN parameter for an explanation of how it affects the compressor.
7.COMP THRESH (-30 to 0): The lower the setting, the more the compression.
8.PRE BASS (-15 dB to +15 dB): The level of the pre-clip bass EQ. Generally for distorted presets this is set to 0 or negative to get a bass cut. For higher gains, these pre-EQ sections do not so much affect the tone of the output, but rather affect the character of the distortion.
9.PRE BASS (40 Hz to 240 Hz): The ‘turnover’ or upper frequency at which the amount of pre bass boost or cut begins to lose effect. Frequencies above this point will still be boosted or cut, just not as much, and as frequency in the signal increases, the amount will diminish to 0. This is a ‘shelf EQ’ type section that remains nominally flat at low frequencies.
10.PRE MID (-15 dB to +15 dB): The level of pre-clip midrange EQ. Generally for distorted presets this is set to a positive value to get a boost in the mids.
See the graph on the next page for a better understanding of the operation of a parametric equalizer.
Note: there are three controls that adjust a parametric equalizer including BOOST – CUT (LEVEL), FREQUENCY or FREQUENCY SWEEP (FREQ) and BANDWIDTH or OCTAVES (BW). The graph below shows an EQ response curve with a center frequency of 100Hz and also at 1KHz. The MID “LEVEL” on the THETA PRO DSP will adjust the amount of Boost or Cut applied to the signal. The MID FREQUENCY, “FREQ” adjusts the center frequency as shown below allowing you to select the center point or peak frequency you are boosting or cutting. The MID BANDWIDTH “BW” is the bandwidth of the frequencies being boosted or cut and is selected as OCTAVES. An OCTAVE setting of .1 will be a narrow band of frequencies that are affected by the boost or cut approximately .1 octaves at 3bd down from the peak frequency. An OCTAVE setting of 2.5 will be a much broader portion of the spectrum that is affected by the boost or cut approximately 2.5 octaves at 3db down from the peak frequency. This type of equalization allows much more precise adjustment of tone shaping than typical Bass, Mid, Treble controls.
11.PRE MID (88 Hz to 6000 Hz): The center frequency of the midrange boost or cut. It is typically set in the 300 to 2000 Hz range.
12.PRE MID (0.1 to 2.5 OCT): The approximate width in octaves of the midrange boost or cut. Beyond this width, the curve will slowly transition back to 0 if the bass and treble are set flat.
13.PRE TREBLE (-15 dB to +15 dB): The level of pre-clip treble EQ.
14.PRE TREBLE (2000 Hz to 12.0kHz): The lower frequency at which the amount of pre treble boost or cut begins to lose effect.
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