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The Signal Path:

The LUNCHBOX 

Acoustic

 has two main channels, one for your acoustic INSTRUMENT and one 

for your favorite MICROPHONE. The Instrument channel has a standard ¼” jack on the top panel 
feeding a Hi-Z preamp for tonal compatibility with most acoustic-electric pickups. The Microphone 
input has two jacks on the rear panel, a standard ¼” and an XLR with switchable 12-volt Phantom 
Power. These feed a Lo-Z preamp to capture the full dynamics of your microphone. All the main 
inputs are protected against RF interference and ground-error overloads. The Instrument and 
Microphone preamps feature separate analog GAIN controls on the top panel for easy adjustment 
of each channel’s input sensitivity.

Following the analog input preamps, the signals are converted to 24-bit PCM digital at a 44.1 
KHz sampling rate. In the digital domain, ZT’s proprietary dynamics and EQ signal processing 
are implemented. Also, channel-specific TREBLE and BASS tone controls with characteristics 
closely following a vintage stack are applied. Additionally, the LUNCHBOX 

Acoustic

 has individual 

REVERB controls, offering the option of different signal echo & decay for Instrument and 
Microphone channels. At this point, the signals are converted back to analog and routed to the 
selectable FEEDBACK CUT circuit. 

The final preamp stage mixes the Instrument and Microphone channels with the stereo AUX 
INPUT (

1

/

8

” jack on rear panel) and routes them to the buffered EFX loop. The EFX SEND can be 

used as a DI or Line output without interrupting the LUNCHBOX 

Acoustic’s

 internal signal path. 

However, plugging into the EFX RETURN will disconnect the internal signal path, replacing it with 
the output from your effects. Finally, an analog master VOLUME is applied to the mix just before 
sending it to the power amplifier.

The output amp section is carefully designed to constantly adapt to the signal characteristics 
and the instantaneous power supply behavior. The amp itself is a pair of Class A/B output 
stages, running fully bridged across the speaker load. The result is very high RMS power, with 
extraordinary additional peak power on top of that. We feel this is the only way to deliver the 
demanding dynamics of acoustic instruments to your audience. The LUNCHBOX 

Acoustic 

includes an adjustable HEADPHONE output and a switchable EXTERNAL SPEAKER jack on the 
rear panel (8 Ω minimum). 

Main Inputs

:

The ¼” INSTRUMENT channel input is located on the top panel of the LUNCHBOX 

Acoustic

. This 

input is shorted when not in use to reduce noise.

The MICROPHONE channel inputs are located on the rear panel of the LUNCHBOX 

Acoustic

 . 

Both ¼” and XLR Microphone inputs are provided, with switchable Phantom Power on the XLR 
input.

Phantom Power:

The LUNCHBOX 

Acoustic

 Microphone channel offers a 12v Phantom Power feature. If you are 

using a condenser microphone, set the Phantom Power switch to On and connect it using a 
standard XLR microphone cable. 

Summary of Contents for LBA1

Page 1: ...Owner s Manual ZT Amplifiers LBA1...

Page 2: ...4 CLEANING Unplug this product from the wall outlet before cleaning Do not use liquid cleaners or aerosol cleaners Use a damp cloth for cleaning 15 NON USE PERIODS This amplifier should be unplugged f...

Page 3: ...AVIS RISQUE DE CHOC ELECTRIQUE NE PAS OUVRIR CAUTION FOR CONTINUED PROTECTION AGAINST FIRE REPLACE ONLY WITH SAME TYPE 250V FUSE Acoustic Vocal Amplifier LBA1 Adjusts the Reverb level Adjusts level of...

Page 4: ...ons giving artists of many styles and genres a consistently great playing experience over the years ZT s research investigation was clean slate We didn t assume we knew any secret magic formula we set...

Page 5: ...nels with the stereo AUX INPUT 1 8 jack on rear panel and routes them to the buffered EFX loop The EFX SEND can be used as a DI or Line output without interrupting the LUNCHBOX Acoustic s internal sig...

Page 6: ...nel In most cases these controls should be set high up generally above the 50 point of their ranges This will assure a good tone and low operating noise Of course you might have to adjust the GAIN con...

Page 7: ...ls and the output volume on your player We recommend that you disconnect any cables from the AUX INPUT when it is not in use EFX Loop Allows effects to be inserted after the input stage resulting in a...

Page 8: ...rols all set at midpoint and the VOLUME all the way down Then inch up the VOLUME step by step Season to taste Because of the high available gain some acoustic instruments may tend to feedback if the G...

Page 9: ...which we believe results in specifications that are both conservative and useful The internal speaker of the LUNCHBOX Acoustic is nominally 8 with a DC resistance of 5 3 Electrically the amplifier ou...

Page 10: ...t 200 watts greater than 130dB 1 meter 3 3 Voltage Switchable 115V 230V Controls Top Panel Dual Channel Volume Gain Bass Treble Reverb Master Volume Feedback Cut Rear Panel Line Out Headphone Level Sp...

Page 11: ...com to explain the defect and to obtain an RMA number return materials authorization number then return the complete product in original packaging if available to an Authorized ZT Amplifiers Service...

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