Behringer T1953 manual Applications, Tube Ultragain as a microphone preamp

TUBE ULTRAGAIN T1953

The LEVEL control

The LEVEL control sets the signal gain at the input of the tube stage. Use this control to adapt the TUBE ULTRAGAIN to either home recording level (-10 dBV) or professional level (+4 dBu). When this level is too low the tube effect becomes less audible and the signal-to-noise ratio deteriorates.

To obtain the best possible signal-to-noise ratio and subsequently the best possible sound, keep an eye on the VU level meter. If the level at the input of the tube stage is to low you will lose the tube sound and have a higher noise floor. Use the CLIP LED above the meter to ensure that the level is not set too high. This LED may light up briefly at signal peaks but should never light up constantly.

When using the TUBE ULTRAGAIN as microphone amplifier, set the LEVEL control to 0 dB for optimum signal-to-noise ratio. Adjust the sensitivity with the MIC TRIM controls. If so desired you can even overdrive the tube stages deliberately to gain a special effect. When the tubes are overdriven severely the effect resembles the overdriving of a guitar amp. This is completely different from the subtle effect of the WARMTH control. Use the controls with discretion, remember: less is more.

The PHASE REVERSE switch

The PHASE REVERSE switch reverses the audio signal’s phase by 180°. Usually, you won’t need this switch. However, in some cases, it might be necessary to reverse the signal phase, for example, if a microphone cable has been connected incorrectly (pins 2 and 3 interchanged), or if several microphones are used and specific circumstances with regard to room acoustics are causing problems (e.g. frequency cancellations are usually caused by phase problems). The phase reverse function will help you locate and eliminate any such problem.

The HIGH PASS switch

When you pick up acoustic signals with microphones, it is usually necessary to eliminate low-end signal portions, such as rumble or pop noise, or other interference frequencies. Often, such frequencies have very high amplitudes and do not only deteriorate the sound quality but can also damage the power amps or speakers. Your TUBE ULTRAGAIN features a tunable high pass filter with a very high slope. Activate the HIGH PASS switch and adjust the FREQUENCY control, so that any disturbing frequencies are faded out as much as possible, with the least damage done to the actual audio signals. Press/toggle the switch several times to make an A/B comparison.

The WARMTH control

The UTC circuitry forms an integral part of the BEHRINGER TUBE ULTRAGAIN. It provides the distinct tube sound. Gently turn the control clockwise to add increasing amounts of harmonics. It improves the transparency of other instruments, particularly those rich in upper harmonics. The WARMTH meters provide an instant overview of the process.

3. APPLICATIONS

This section describes some typical applications of the BEHRINGER TUBE ULTRAGAIN. Starting from the following basic settings you can use it to solve the majority of audio problems.

Please take your time to study the application examples, so as to be able to fully exploit the TUBE ULTRAGAIN and its variety of features.

Basically, the TUBE ULTRAGAIN can be used in five areas of application:

1.Using the TUBE ULTRAGAIN as a high-quality microphone preamp.

2.Using the TUBE ULTRAGAIN to convert home recording to studio levels, and vice versa.

3.Using the TUBE ULTRAGAIN to balance unbalanced signals (DI-box).

4.Using the TUBE ULTRAGAIN to enhance the sound of the program material by adding “tube warmth”.

3.1 The TUBE ULTRAGAIN as a microphone preamp

Hook up a microphone and set the basics setting as described in chapter 2. Turn the WARMTH control fully counterclockwise and you have a very pure and neutral mic preamp with excellent noise and distortion figures. Turn the WARMTH control clockwise to increase the tube sound with the UTC tube stage.

3. APPLICATIONS 11