MARSHALL AS50R
Owner's Manual

ENGLISH

WARNING! - Important safety instructions
A. ALWAYS fit a good quality mains plug conforming to the latest B.S.I. standards where necessary (UK only). B. NEVER attempt to by-pass the fuses or fit ones of the incorrect value. C. NEVER attempt to replace fuses or valves with the amplifier connected to the mains. D. DO NOT attempt to remove the amplifier chassis, there are no user serviceable parts. E. Refer all servicing to qualified service personnel. Servicing is required when the apparatus has been damaged in any way, such as the power supply cord or plug is damaged, liquid has been spilled or objects have fallen into the apparatus, the apparatus has been exposed to rain or moisture, does not operate normally or has been dropped. F. NEVER use an amplifier in damp or wet conditions. G. ALWAYS unplug this apparatus during lightning storms or when unused for long periods of time. H. Protect the power cord from being walked on or pinched particularly at plugs, convenience receptacles and at the point where they exit from the apparatus. I. DO NOT switch the amplifier on without the loudspeaker connected. J. ENSURE that any extension cabinets used are of the correct impedance. K. PLEASE read this instruction manual carefully before switching on. Follow all instructions and heed all warnings. WARNING : This apparatus must be earthed! WARNING : Do not obstruct ventilation grille and always ensure free movement of air around the amplifier! USA ONLY - DO NOT defeat the purpose of the polarised or grounding type plug. A polarised plug has two blades with one wider than the other. A grounding type plug has two blades and a third grounding prong. The wide blade or the third prong are provided for your safety. When the provided plug does not fit into your outlet, consult an electrician for replacement of the obsolete outlet.

AS50R Front Panel Features Channel 1 - Acoustic Instrument Channel
1. Input Jack
Plug the lead from your guitar in here. The high impedance of this input will help you to get the best from the passive or active piezo or magnetic pick-ups. but not too harsh. It is worth noting that set in higher positions, this control will induce a certain amount of noise.

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Master Section
11. Chorus Assign Switches
Allows the built in chorus effect to be selected on either channel individually or both channels together.

2. Volume Control
Controls the volume level of the Acoustic Instrument channel. A good place to start with this control is the half way, or 12 o clock position, then adjust according to the sensitivity of your pick-up.

12. Chorus Speed Control
Controls the speed of change of frequency for the built-in chorus effect.

3. Bass Control

Adjusts the amount of bass, or bottom end of the instrument�s tone. Care should be taken when setting this control as adding excessive bass can cause unnatural howling. Again, the half way position is the best place to start. Adjusts the treble, or top end of your sound. Careful adjustment will make your high notes lively but not too harsh. It is worth noting that set in higher positions, this control will induce a certain amount of noise.

13. Chorus Depth Control
Controls the amount of change of the frequency shift for the built-in chorus effect. Note: When using the chorus, higher speed settings usually sound better with lower depth settings and vice versa. Experiment to find which selection suits you best.

4. Treble Control

14. Reverb Balance Control
Controls the balance of the Reverb effect and the parallel effects loop between channel 1 and channel 2.

Channel 2 - Microphone Channel
5. Phono Inputs
Inputs to take connection from a tape or CD player.

15. Reverb Level Control
Controls the overall level of the reverb effect.

KEEP THESE INSTRUCTIONS

16. Phase Switch
Switching the phase can considerably reduce the amount of low frequency acoustic feedback.

Introduction
The AS50R is a compact and portable 50 watt combo amplifier specially designed for use with acoustic instruments. Between its two channels, this combo has the flexibility to handle instruments with transducers, such as piezo or magnetic pick-ups (channel 1), or microphone for either vocal or instrument reproduction (channel 2). The built-in Chorus effect is assignable to either or both channels and the reverb can be controlled and balanced between the channels to create just the right ambience. If you want to add further effects, then there is an on-board parallel effects loop which can be balanced between the channels in the same way as the reverb. One of the most difficult aspects of amplifying some acoustic instruments is feedback. To help you eliminate this, the AS50R features several �anti-feedback� controls, including a Phase switch and a frequency controllable Notch Filter. The combination of these two elements will give you precise control of the frequencies where feedback is likely to occur and help you to eliminate them. For clear and detailed performance, the AS50R is loaded with two 8� speakers and a high efficiency piezo tweeter. There is also an internal limiter which allows you to push the maximum level from the 50 Watt output, whilst remaining distortion free. Neat and compact, flexible and portable, the AS50R is the ideal amplifier for the acoustic player who wants a system as suitable for small gigs as it is at home.

6. Microphone Input
Balanced XLR type input for connection of a microphone and suitable for vocal or instrument applications.

17. Notch Filter Switch
Further feedback reduction can be achieved using the selectable frequency notch filter. When activated, the filter cuts by 10dB the frequency selected using the rotary control (item 18).

7. Jack Input
Input to take any source, such as drum machine, keyboard etc.

18. Frequency Control
If feedback occurs when the Master Volume is set to the desired performance level, select the switch (item 17) and rotate this control until the offending frequency is eliminated.

8. Volume Control
Controls the volume level of the Microphone Aux channel. A good place to start with this control is the half way, or 12 o clock position, then adjust according to the sensitivity of your pick-up

19. Master Volume
Controls the overall volume output from the amplifier.

9. Bass Control
Adjusts the amount of bass, or bottom end of your sound. Care should be taken when setting this control as adding excessive bass can cause unnatural howling. Again, the half way position is probably the best place to start.

20. Power switch
Turns the amplifier on/off, with neon indicator to show the �on� position.

18. Treble Control
Adjusts the treble, or top end of your sound. Careful adjustment will make your high notes lively

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