How to use the Mojave Line out feature.

Published on 17 February 2014 in Mojave News and tagged , , , , , , . Bookmark the permalink.

Mojave Ampworks CoyoteEach Mojave amp built incorporates a “Line Level Output” on the back of the amp. Unlike traditional line outs which are derived from the preamp, the Mojave line out is derived from the final output stage, the speaker jack. How does this differ you may ask? In one word, greatly. The signal from the speaker output jack is what the amplifier is sending down to the speaker cabinet and in essence, the entire sound of the amp and all things created from the front to the back of the amplifier itself. Traditional line outs only give you an amplified signal that would be tapped from the preamp before processing through the final power amp stage and this signal is missing all the good stuff. For all intents and purposes, this type of line out is intended to be sent to a slave amplifier. In the world of preamp distortion, this may be all that is needed but the true sound of the amp is bypassed.

In the Mojave amplifier, there is no preamp distortion. This means there are no overdrives to be sent either to a line output or an EFX loop. The Mojave amplifier creates it’s distortions in the power amp section and thereby includes the rich harmonics that are created in the final stages such as the phase inverter, the power tubes and most importantly, the output transformer.  In this case, you can successfully capture all the same rich sounds being sent to your speaker cabinet without having to use a “Microphone” on your speaker cabinet as would be the case in many instances such as studio recordings or live sound reinforcement.  With the line level signal you can send this rich sound from your speaker jack and feed it to your favorite sound EFX. The processed sound that is now created is rich with the power tube and output transformer harmonics and characteristics that are so important to the amplifiers sound to begin with.

Once the line out signal is developed with the EFX you desire, the signal is ready for re-amplification to a clean power amp and speaker. This amp and speaker are separate from the Mojave amp and are dedicated to the EFX sound. This is known as the WET sound. The WET sound is fully processed and can be added to your dry sound that is coming from your Mojave amp and cab which are direct and unprocessed. On the back of the line output is an adjustable level control The adjustment allows you to set the desired line out level so you can both set a correct signal level to drive your EFX and simultaneously drive your signal level into your wet power amp and speaker. Now this means you have one control on your amp controlling the entire chain for your EFX fed from your Mojave amp. If you wish to turn the EFX or WET signal off entirely, you can simply turn the line level down to zero. If you wish to blend in some EFX with your dry sound but not make it to overwhelming, simply turn the line level up to the desired mixed level.

Why do all this? The biggest reason is the ability to capture the signal from the power stage and process this signal with time based EFX without the wash and blur that commonly happens when you send time based EFX into an amp that is distorting these signals.

A second and most valuable part is this. The transparency you can achieve using this method produces the most organic color of your sound and allows your clarity to ring through far and above the most elaborate algorithms in the processing world of processor products trying to give you this very effect. There are also spacial enhancements that provide benefit in your rigs sound.

The final feature commonly overlooked on the line out feature is a ground lift provided on the line out level adjustment control. This is achieved via a push pull pot. When the pot is pushed in, or in normal operation, the signal is grounded to the amplifier. If the pot is pulled out. The ground is floating allowing it to reference the power supply of the secondary amplifier preventing ground loop hum if a hum were to develop. This can help to alleviate unwanted hums or noises that can occur when two or more amps are tied together.

I have included some sound demos where the Line out was employed and recorded. The speaker on the left should be completely dry and the speaker on the right is the sound of the line out fed from the Mojave line out jack, through the EFX and amplified from a clean power amp and speaker. What you hear in the recording is exactly what it sounded like live. The last example was mic’ed so it is not separated by speaker but one amp, the WET was running and the dry was running together. The WET was delay.

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