TRANSFORMER-OPTION - USER INFORMATION
Contents
1. Cali 76 FET BASED STUDIO STYLE LIMITING AMPLIFIER TRANSFORMER OP TION USER INFORMATION Sie SS LINE DI DI PAD ON LINE PAD OFF Made in the UK by Origin Effects Keats Audio For support please visit www origineffects com Key Features Figure 1 Transformer Option Rear Panel left to right INSTRUMENT input connection GND ground lift switch LINE DI balanced output PAD pad attenuation switch POWER power supply connection GAIN gain e Custom designed transformer driving a switch AMPLIFIER unbalanced output to drive instrument amplifier e 100 Class A discrete output amplifier pair of outputs e Unbalanced instrument level output e Balanced line level output e Ground lift function to eliminate ground induced hum balanced output only e Signal pad for DI balanced output only e Gain switch adjusts level through transformer circuitry for increased amplifier transformer saturation e Auto Shut Down effectively returns pedal to stock format when powered from a battery or low voltage supply The Cali76 is a premium quality 1960s style FET compressor inspired by the legendary Urei 1176 The transformer option works in conjunction with the pedal to provide the user with additional tone options and connectivity A custom designed transformer sits at the heart of the unit The core size and material have been selected to contribu2. that shuts down the transformer board when a low voltage supply is detected this applies to external supplies as well as internal battery usage At low voltages the signal is diverted around the transformer circuitry via a high quality relay The signal path is therefore electronically identical to the standard Cali76 and only the INSTRUMENT input POWER and AMPLIFIER output connections remain active In this scenario all rear panel switches become inactive When using an 18V supply the transformer circuitry springs to life and the relay routes the signal through the transformer board We ve designed the board around an 18V supply Using a lower supply voltage may result in the pedal intermittently switching between transformer enabled and transformer bypass modes As always higher supply voltages can cause damage to sensitive electronic components Output Connections Type and Suggested Usage The standard Cali76 features a single medium impedance output This can be used to connect the pedal to any high impedance input such as the input of a guitar bass amplifier In contrast the transformer enabled pedal offers two ultra low impedance outputs suitable for driving almost any audio input connection The AMPLIFIER output provides an unbalanced signal referenced to ground This is ideal for connecting to your guitar bass amplifier The LINE DI output provides a fully balanced signal via a TRS output so
3. cket and can be used to connect to recording consoles mixers sound cards mic preamplifiers etc The PAD switch can be used to drop the signal by around 28dB and this should give the user enough range to be able to plug into both line level and mic level inputs The GND switch ground lift can be used to cure annoying hums and other ground loop related issues Usefully the LINE DI output can be used to feed the input of a second guitar bass amplifier by simply using a standard mono guitar lead The ground lift function is a must here as it will dispense with the ground loop related hum normally generated when Y connecting amplifier inputs especially true when connecting the inputs of high gain amplifiers Headroom Adjustments GAIN Switch Of all the functions this one s most likely to cause confusion This switch changes the gain of the output amplifier i e the amplifier driving the primary of the output transformer The LOW setting is the stock normal setting Using the HIGH setting boosts the internal gain by around 9dB The LOW setting is clean and dynamic However when using the HIGH setting you ll notice that the output amplifier and transformer begin to run out of headroom Overall the sound is richer in harmonics becoming edgy sounding and ultimately clipping The change in gain can be clearly heard when using the LINE DI outputs Using the GAIN switch will therefore require small
4. company Keats Audio Simon has worked for a number of big name audio companies on a full time basis and as a design consultant Simon can be reached by email telephone or by post and will be happy to help with any enquiries Email simon origineffects com Telephone 0800 810 1070 International 44 800 810 1070 Address Simon Keats Origin Effects First Floor Office Unit C6 Station Yard Thame Oxfordshire OX9 3UH UK Simon Keats Origin Effects is not affiliated with Urei or Universal Audio in any way This product draws inspiration from the Urei 1176 compressor but does not feature any like for like circuitry He 5 am E J TE a Figure 4 Cali76 with Transformer Option circuit board installed
5. level adjustments to be made on any connected mixing consoles etc In contrast the AMPLIFIER output remains at a consistent level due to a variable passive attenuator network that perfectly counter acts the level shifting effects of the GAIN switch This allows you to monitor the shifting tonal effects through your guitar bass rig without having to tweak your amplifier s volume control Bypass Mode When actively engaged through the use of an 18V supply the transformer board effectively buffers the signal at all times even when the unit is set to Bypass Please note that True Bypass will only be operational when powering the unit from a battery or 9V external supply This isn t really a negative point as the Buffered Bypass system is technically superior but is certainly worthy of a mention Further more any saturation overdrive experienced with the GAIN switch set in the HIGH position may also be audible with the unit set to bypass just like driving a Urei 1176 with the compression bypassed defeated If this proves to be a problem you may want to consider purchasing an external bypass looper in order to fully bypass the Cali76 Using an external bypass looper would give you three useful pre sets dry signal transformer coloured dry signal and lastly compressed signal also with transformer colouration Cali 76 About the Designer Origin products are currently being developed by Simon Keats of UK
6. te harmonics Figure 2 Transformer Option circuit boards Board on left features standard when driven by the Class A transistor custom designed transformer Board on right features high linearity broad based output stage spectrum Lundahl transformer Cali 76 Installation At the time of publication the transformer option is only available to those customers purchasing a brand new Cali76 pedal directly from Origin Effects The option will be installed as part of the manufacturing process carried out in the UK alongside the rest of our production A retro fit service may become available in the future depending on demand Power Requirements Battery vs Supply Operation The transformer option requires a relatively large amount of supply current in comparison to the standard Cali76 The extra current is put to use by the Class A transistor output stage in order to drive problematic loads with ease such as long cable runs as well as the low impedance inputs of some vintage studio equipment Just as importantly the extra current drive can be used to push the output transformer into saturation This generates frequency dependant harmonics and subtle overdrive Unfortunately a standard 9V battery just couldn t supply this level of current for long enough to be practical as the user would need to change batteries every few hours to maintain optimum results For this reason we decided to opt for an automatic system
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