THERMIONIC CULTURE THE PHOENIX valve compressor OPERATING MANUAL WARNING Please read this operating manual thoroughly before using the equipment. To reduce the risk of electric shock, it is essential that the unit is disconnected from the mains supply before any of the covers are removed. Please also note that the power supply capacitors within this unit can remain charged even after the mains supply has been disconnected. It is essential that these capacitors are discharged after the mains supply has been disconnected and the covers have been removed. ©Thermionic Culture Ltd, January 1999 1 CONTENTS Section Page 1 Introduction 3 2 Controls & Operation 4 2.1 Output trim 4 2.2 Gain 4 2.3 Attack 4 2.4 Release 4 2.5 Threshold 5 2.6 Bypass 5 2.7 Link 5 2.8 Pre-sets 6 2.9 Meters 6 3 4 Servicing & Maintenance 7 3.1 Valves 7 3.2 Operating voltage / Fuses 7 Specification ©Thermionic Culture Ltd, January 1999 8 2 1 Introduction The Phoenix is a stereo compressor which can be used as a pair of mono compressors. It has a ‘soft knee’ or ‘variable mu’ characteristic in that the compression ratio increases with the amount of compression being used. Initial compression is 1.2:1 increasing to 5:1 at 15dB compression. ©Thermionic Culture Ltd, January 1999 3 2 Controls & operation 2.1 Output Trim Control This control is used to trim the output levels when compressing a stereo mix. Its function occurs after the electronics and therefore reduces the maximum output level (MOL) and noise. For operation at line level (+4dBV), this control is best left at around 7. For -10dBV operation it should be set to 2. 2.2 Gain Control For line level and medium compression, this control should be set, typically, to between 3 and 5. 2.3 Attack Control The attack control varies the rate at which the compressor starts to react. Attack rates of between 4ms (fully anti-clockwise) and 120ms (fully clockwise) can be achieved. This control is typically set to 3 for normal operation. Slow attack rates make the compressor less efficient, but can be effective for percussion. 2.4 Release Control The release control varies the rate at which the compressor ‘lets go’ of the input signal. Release varies from 60ms (fully anti-clockwise) to 2.2s (fully clockwise), typically. Faster release times can give rise to low frequency distortion. A typical setting for normal operation of the release control is 3. ©Thermionic Culture Ltd, January 1999 4 N.B. The compressor will become inefficient if very slow attack and very fast release times are used. However, this can be used to advantage if ‘thumping’ bass effects are required. 2.5 Threshold Control The threshold control is used to adjust the amount of compression in conjunction with the input level. With the control in the fully clockwise position, there will be no compression. Turning the control anti-clockwise increases the amount of compression. 2.6 Bypass This control totally bypasses the compressors, by linking the inputs to the outputs. 2.7 Link Links the two compressors for compressing a stereo track. All controls are still in use, so both channels should be set to around the same setting. Ideally, a 1kHz tone should be used to setup the levels so that both channels’ inputs and outputs are equal. In practice, this is not always necessary. In another application, the link control can be used to allow one compressor to control the other in a mono application. For example, to increase the high end compression, use the channel 1 compressor as the signal path and feed an equalised version of the same signal with additional top lift into channel 2. Turn off the compression to channel 1 by turning the threshold control fully clockwise. The opposite applies to ©Thermionic Culture Ltd, January 1999 5 channel 2. Channel 2 controls channel 1 when link is in. 2.8 Pre-sets There are four pre-sets on the compressor chassis. The two just behind the front panel controls are to adjust for minimum low frequency distortion. They are set up with an oscilloscope for minimum distortion and phase shift at 40Hz. These pre-sets should not be adjusted, unless the valves are changed. The two pre-sets behind the meters are used to adjust the zero points of the meters. They can be adjusted with a long thin screwdriver, without removing the top cover of the compressor. Zero readings will vary a little with mains voltage and valve ageing. The zero setting is not critical, but both must be the same if compressing a stereo track. 2.9 Meters The Phoenix can operate much faster than the meters will read. The meter scales should be used as a guide. Actual compression will vary slightly with individual valves and the meters may not be accurate at high readings. ©Thermionic Culture Ltd, January 1999 6 3 Servicing & Maintenance 3.1 Valves All valves are selected to ensure that the unit gives optimum performance. Input valves are always matched when the unit is calibrated to ensure consistent performance across both channels. Although Thermionic Culture Ltd guarantees the valves for twelve months, they can last for up to twenty years. Spares can be obtained in matched pairs from Thermionic Culture Ltd. 3.2 Operating voltage / Fuses The Phoenix Valve Compressor is factory set to operate from a 230V 50/60Hz AC mains supply It can be set to operate from 115V AC by sliding the voltage selector switch on the rear panel to the ‘115V’ position. NOTE: If the mains supply voltage is reduced to 115V, then the mains fuse MUST be increased to 1.6A in accordance with the following table: Operating Voltage 115V 230V ©Thermionic Culture Ltd, January 1999 Fuse Rating T1.6A 20mm type T800mA 20mm type 7 4 Specification Max. o/p level (MOL): +19dB into 600Ω +24dB into 10kΩ Max gain: 30dB. THD (at no compression): better than 0.09% @ 1kHz 0.1% @ 100Hz Noise, IEC weighted: 95dB below MOL. Input impedance: 15kΩ. Frequency response: <1dB variation over range of 12Hz to 56kHz. Attack time: 0.004s to 0.12s Release time: 0.06s to 2.2s Output impedance: 600Ω Distortion will increase with compression, typically 0.2% & 0.25% at 1kHz & 100Hz with 8dB compression. VALVE COMPLEMENT (2 ea): Input/Compression: 6BQ7A (equiv. CV5365) or PCC85 (equiv. 9AQ8) in units with ‘P’ suffix to serial number. NB. These must be accurately matched. Output: 12AT7 (equiv. ECC81, CV4024, 33A/101K etc.). Side chain detector: 6AL5 (equiv. EB91, CV4007, CV4025). ©Thermionic Culture Ltd, January 1999 8 Thermionic Culture Ltd. 83 Collins Meadow, Harlow, Essex, CM19 4EL, UK Tel: +44 (0)1279 414770 Fax: +44 (0)1279 412233 ©Thermionic Culture Ltd., January 1999. Printed in UK.
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