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Related Manuals for Oldfield Amplifiers 6440-OD
Summary of Contents for Oldfield Amplifiers 6440-OD
- Page 1 Oldfield Amplifiers User Guide Model 6440-OD...
- Page 2 Oldfield Amplifiers User Guide Important Safety Instructions For your safety read, retain, and follow all instructions. Heed all warnings. • Only connect the power supply cord to an earth-grounded AC receptacle. This amplifier is designed • to operate on standard North American 115V AC and should only be plugged in to a receptacle meeting those specifications. WARNING: To prevent damage, fire or shock hazard, do not expose this unit to rain or moisture. • Unplug the power supply cord before cleaning the unit exterior (use a damp cloth only). Wait until • the unit is completely dry before reconnecting it to power. • Maintain at least 6 inches (15.25 cm) of unobstructed air space behind the unit to allow for proper ventilation and cooling of the unit. •...
- Page 3 Oldfield Amplifiers User Guide Front Panel: Controls And Features 1 • Inputs - Hi / Lo: This is the input for musical instruments. Use the Hi Input for the highest gain and the Lo Input for less volume or higher gain instruments. 2 • Boost Switches: Switch the Mid-Boost Switch to the on position to give the amplifier more mid range bite. When this switch is in the on position the amplifier will obtain distortion slightly faster than when the switch is in the off position. The Mid-boost switch must be in the on position when controlling the function with the foot switch. Move the Bright Switch to the on position to give the amplifier more top end bite. This function is front panel selectable only and can not be controlled by the foot switch. 3• Volume: This control determines the overall amount of gain for the clean channel of the amplifier. As the volume control is rotated towards max the amp will become not only louder but rich harmonic overtones will mix with the tone as well. 4 • Treble: This control determines the amount of treble frequencies present in the amplifier tone. At the max setting the amplifier is at it’s brightest. This control also adds a bit of bite to the amplifier as it is turned towards max. 5• Middle: This control determines the amount of mid frequencies present in the amplifier tone. The mid control effects are less dramatic than the treble and bass controls and tend to soften the overall amp tone as the control is turned towards the maximum setting. It should also be noted that as the middle control is turned towards the maximum setting the player will notice that the treble and bass controls have less effect on the overall tone. 6 • Bass: The bass control determines the amount of bass frequencies present in the tone. Turning this control too far towards maximum could result in causing the overall tone to seem too muddy. towards max the tone will become more compressed and distorted. 7 • OD Gain: The OD Gain control determines the amount of Overdrive signal that is fed from the first overdrive gain stage to the second overdrive gain stage. As this control is turned towards max the tone will become more compressed and distorted. 8 • OD Level: The OD Level control determines the amount of Overdrive signal that is fed from the Second...
- Page 4 Oldfield Amplifiers User Guide Front Panel: Controls And Features - Continued 9 • Master: The Master control determines the overall loudness of the amplifier. 10 • Reverb Dwell: This control determines the gain (strength) of the amplifier reverb. 11 • Reverb Mix: This control mixes the reverb and the dry signal. Note - Use the Dwell and the Mix control together to find the reverb sound that works best for you. 12 • Speed: This controls the speed of the amplifier tremolo. As the speed control is rotated towards maximum the amplifiers tremolo will speed up. 13 • Intensity: This control determines the amount tremolo in the amplifier signal. 14 • Pilot Light: Illuminated when the amplifier is on. 15 • Standby: Switch to On to play through the amplifier. Do not take the amplifier out of Standby for at least 30 seconds after turning the Mains On to give the tubes time to warm up to operating temperature. 16 • Mains: Switch to On to power on the amplifier.
- Page 5 Oldfield Amplifiers User Guide Rear Panel: Controls And Features 1 • Fuse: Slo Blo fuse. Replace only with recommended value stamped on the back of your amplifier. Failure to comply with the recommended value could seriously damage the unit. 2 • Rectifier Selector: The switch will allow you to go between a tube rectifier and a solid state rectifier. The solid state rectifier will give the tone a slightly tighter feel than the tube rectifier. Do not change rectifier settings unless the amplifier is in Standby Mode. 3 • Pentode / Triode : Allows user to select between full and half power output. Do not change power settings unless the amplifier is in Standby Mode. 4 • Bias Adjust: Allows a technician to adjust power output tube bias. 5 • Impedance Selector: Set the impedance selector to match the impedance of the attached speakers. 6 • Main Speaker Jack: Connect the main amplifier speaker to this jack. 7 • External Speaker Jack: An external speaker can be connected to this jack. Note - A speaker must be connected to one of the speaker jacks at all times. Failure to do so will result in serious damage to the unit. 8• Line Out: The line out jack provides a speaker emulated signal that can be send to an external amplifier or PA. 9 • OD Trim: The OD Trim control determines the amount of Clean signal that is fed from the output of the clean channel to the first overdrive gain stage. As this control is turned towards max the tone will become more compressed and distorted. 10 • Reverb Out: Connect the output lead from the reverb tank to this jack. 11 • Reverb In: Connect the input lead from the reverb tank to this jack.
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Page 6: User Guide
Oldfield Amplifiers User Guide Rear Panel: Controls And Features - Continued 12 • Clean / OD Switch: This switch selects the clean or overdrive channel. When using the foot pedal this switch should be in the OD position. 13• Footswitch: Connect the input 1/4” jack on the foot pedal to this jack to control switching from clean to overdrive using the foot pedal. - Page 7 Oldfield Amplifiers User Guide Tubes Tube layout as viewed left to right: • Rectifier - 5R4 or GZ34 • Power Tubes - (2) 6L6 • Phase Inverter - 12AX7 • Tremolo Driver - 12AX7 or 12AY7 • Reverb Driver - 12AX7 •...
- Page 8 Oldfield Amplifiers User Guide Notes About Setting Up The Overdrive When setting up the overdrive channel the player needs to be aware how the audio signal flows through the amplifier. Keep the following items in mind when dialing in the overdrive channel. 1. Start with getting the clean tone that you want from the amp using the volume, tone and master volume controls. 2. The output from the clean channel feeds the input of the overdrive channel after all the tone control settings have been applied to the audio signal. The strength of the signal that gets sent to the overdrive channel is determined by the OD Trim control setting on the back of the amp. Turning the OD Trim up will also add some depth to the overdrive tone. 3. The OD Gain control receives the audio signal after the first overdrive gain stage and determines how much of that signal is sent to the second overdrive gain stage. Too much OD Gain and the tone can become fizzy. 4. The OD Level control receives the audio signal from the second gain stage and determines how much of that signal is sent to the master volume. This control is very useful in matching the clean channel volume with the OD channel volume. Using these four gain controls together will allow the player to dial in the type of overdrive tone they are looking for. Keep in mind that this is a complex gain structure and it may take the player a little time to understand how each control affects the overall tone.
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Page 9: Warranty
Oldfield Amplifiers User Guide Warranty The following warranties apply to the original owner of the amplifier. All warranty work must be performed by Oldfield for the warranty to be in effect. Warranties do not cover normal wear and tear or abuse. Failure to comply with the safety precautions outlined earlier in the owner’s manual will void all warranties. Rectifier and Power Tubes – Guaranteed for thirty days after date of purchase. If a failure occurs Oldfield will replace any rectifier or power tube during this period free of charge. Power tubes can only be replaced by a qualified service technician since a re-bias may be necessary. Preamp Tubes - Guaranteed for ninety days after date of purchase. If a failure occurs Oldfield will replace any preamp tube during this period free of charge. Power Transformer, Output Transformer, Reverb Transformer, And Choke - These items are guaranteed for ten years after date of purchase against manufacturer’s defects. If a failure occurs due a defect in manufacturing Oldfield will replace any of these items during this period free of charge. Warranties on these items are void if the owner uses any type of power soak or attenuator in conjunction with the operation of the amplifier. Defects Due To Workmanship – Oldfield guarantees the amplifier to be free from workmanship defects for 5 years from the purchase date. Circuit Components – Any failed circuit component will be replaced at Oldfield’s discretion. Some circuit components have a limited life such as filter and bypass capacitors and Oldfield must use judgment to determine if the component was at end of life or failed prematurely. In every case Oldfield guarantees to work with the customer to remedy any situation in a timely manner and to the satisfaction of the amplifier owner.
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