Congratulations on the purchase of your new RANDALL MODEL 667 Amplifier! We at Randall Amplification appreciate that you chose the 667 Amplifier and wish you years with tons of gain, great tone and enjoyable playing time. Engineered by world renowned amp guru, Mike Fortin, this amplifier is the result of countless hours of listening tweaking and perfecting the tight and relentless attack that this collection of channel circuits deliver.
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Six Channels of Pre-amp - overview:! CHx: Selects your channel and GAINx , BRIGHT switch, and VOLx. GAINx: Overall gain control. BRIGHT: 3 way high frequency boost that becomes less active as GAINx control is increased. VOLx: Channel volume control to balance output between other channels. It affects the SEND levels of the FX LOOP. TSS: 3 way switch that shifts the frequency point of the tone stack to better match the amplifier to different speaker types and room sizes.
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VOICING L: For Channels 1 & 2, there is always 3 stages of tube gain to keep the harmonic content, voicing L scoops out the mids. For Channels 3 & 4 / 5 & 6. Selects 2-12AX7 preamp gain stages. This is excellent for players that love that wide open, late 60’s vibe. This is the lowest gain setting of the 667. The BOOST switch is inactive in this mode.
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FX LOOPS Functions:! SERIES FX LOOP: This basically works as an insert patch point. The SEND jack plugs into the effects unit’s input jack. The RETURN jack plugs into the effects unit’s output jack. The audio path of the amplifier is interrupted and 100% of the signal is being sent to the SEND jack. It must be noted that when nothing is plugged into the SERIES selected FX LOOP and the FX switch is in the on, no sound will be heard out of the speakers.
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Only a small volume reduction and slight tonal change will occur. Biasing the 667 amp is simple and does not require removal of the chassis. You will need a simple voltmeter or digital multimeter set to the lowest DC voltage range, typically 200mV (millivolts).
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