T25 Tube Compressor OPERATOR’S MANUAL Written for Automated Processes Incorporated by Dan Pfeifer Rev.
Table of Contents About This Manual ...................................................................................... 1 1.0 Introduction ......................................................................................... 3 1.1 Features ..................................................................................................... 3 2.0 Quick Start............................................................................................ 4 3.0 Overview .....................................
About This Manual This manual explains the operation and applications of the API Select T25 Tube Compressor. This manual is organized in sections that correspond to the front panel controls and rear panel interface.
Important Safety Instructions 1. Please read these instructions 2. Keep this information in a safe place 3. Do not use this device near water 4. Clean only with a dry cloth 5. This product uses high-voltage vacuum tube technology. To avoid a potentially-lethal shock, handle it with care. Never open the lid when the unit is on. 6. Wait at least 5 minutes after the unit has been unplugged before opening the lid to replace tubes. Reinstall lid before powering. 7.
1.0 Introduction Welcome to the API Select line of premium tube-based audio processors and thank you for choosing the T25 Tube Compressor. The T25 is a classic 2-channel, F.E.T. feedback-style compressor/limiter with a Class-A tube output stage that utilizes a custom API transformer. Built with 12AT7WC and 12BH7 dual-triode vacuum tubes, the T25 represents the next step in API’s compression technology and new vistas of tonal shaping while retaining the unmistakable API sound quality.
2.0 Quick Start One tip to get started: We try to design all of our processing modules with the understanding that there is never enough time to read a manual and learn all of the features in the 10 seconds that is allowed during a setup. If you simply set all of the parameters as follows the T25 will have a useful, but conservative effect on the signal.
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4.0 Compressor Controls Each channel of the T25 is equipped with a comprehensive set of compression parameters. 4.1 Attack Time ATTACK: Sets the time it takes the compressor to react when levels exceed the set THRESHOLD • 20µS to .8mS range • 11-step switch 4.2 Release Time RELEASE: Sets the time it takes the compressor to recover to unity gain after levels fall below the set THRESHOLD • 50mS to 1.2S range • 11-step switch 4.3 Ratio RATIO: Simultaneously sets the compression ratio (input vs.
5.0 Side-Chain and Routing Controls The T25 Tube Compressor is equipped with a flexible set of side-chain processes and routing controls. Frequency-dependent side-chain processing includes a de-esser and the patented THRUST® filter that helps you get more punch from audio with heavy low-frequency content. These features provide increased control of the tonal characteristics and envelope shaping the compression applies to the audio.
5.3 IN/out Switch The IN switch is a soft IN/out button that defeats the compression action silently, but allows the signal to pass through the FET amplifier and tube circuitry. IN: Toggle to switch compression IN or out • Activates gain reduction when engaged • Audio passes through T25 circuitry without gain reduction when disengaged • Illuminates when engaged 5.
6.0 Level Indication Each channel of the T25 Tube Compressor is equipped with a LED gain reduction meter, a peak indicator, and output level VU meter for level indication. 6.1 Gain Reduction Meter & Peak Indicator GR (Gain Reduction): Indicates the amount of gain reduction in decibels (dB) • Up to ten red LEDs illuminate to provide accurate indication of gain reduction PEAK: Indicates when output level reaches or exceeds +18dBu • Red LED 6.
8.0 Power Switch & Rear Panel Connections 8.1 Power Switch The power switch for the T25 Tube Compressor is located on the right side of the front panel. Power: Toggle to power the T25 ON and off NOTE: The T25 is a tube-based processor that requires 15 minutes for the tubes to warm-up to a stable temperature before tonal qualities become consistent. 8.
APPENDIX A1 Specifications A2 Block Diagram A3 Recall Chart A4 User Accessible Maintenance A5 API Limited Warranty and Service T25 Tube Compressor 11 API Select
A1 Technical Specifications • • • • • • • • • • • • • • Input Impedance: 20kΩ Output impedance: 75 ohms, can drive 600 ohm loads Maximum output level: +24dBu Frequency Response: 20Hz – 40kHz (+0dB / -1dB) Ratios: 2:1, 4:1, 8:1, 20:1 (switchable) Attack Times: 20µs – 0.8ms Release Times: 50ms to 1.2s Total Gain: +40dB, IN/OUT both fully CW SNR: 90dB Power Consumption: 45W Size: 19” x 3.5” x 12” Deep Size (Boxed for Shipping): 21” x 9” x 15” Actual Weight: 14 lbs. Shipping Weight: 17 lbs.
A3 Recall Chart T25 Tube Compressor 13 API Select
A4 User Accessible Maintenance A4.1 Tube Replacement The T25 Tube Compressor features 12AT7WC and 12BH7 dual-triode vacuum tubes in each channel. The factory installed tubes are selected at API for optimal performance. All tubes are socketed and can be replaced if required.
A5 API Limited Warranty and Service Information a) Warranty Information: API products carry a one year factory service and five year parts warranty from date of purchase. API (Automated Processes, Incorporated) does not cover claims for damage due to alteration and/or abuse. This warranty is limited to failures during normal use, which are due to defects in material or workmanship.
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