Sabre User's Manual Aiken Amplification, Inc. 1225 Montague Avenue Greenwood, SC 29649 Tel: 864-993-8383 http://www.aikenamps.
Contents Contents...............................................................................................................2 Getting Started.....................................................................................................3 Front Panel Controls and Switches...................................................................4 Rear Panel Controls and Switches....................................................................7 Tube layout and replacement.................................
Getting Started Congratulations on purchasing your new Aiken Sabre amplifier! The Sabre is a 50W channel-switching amplifier featuring two EL34 tubes in the output stage. There are two completely separate channels, each featuring Gain, Bass, Middle, Treble, and Master controls, with a common Presence control, as well as two separate effects loops allowing individual effects to be used for each channel.
Front Panel Controls and Switches Input jack: Plug your guitar in here and you are ready to rock! Ch1/2 select switch: This switch selects either the clean channel or the distortion channel. It should be in the “up”, or channel 2 position to enable normal footswitch operation, as it will override the footswitch setting. The red and green channel indicator LEDs will alternately illuminate when their channel is selected. Ch 2 gain switch: This switch turns on the gain boost function of channel 2.
Channel 1 Treble: The treble control adjusts the high frequency equalization of the clean channel. Channel 1 Master: The output level control is the overall level control for the clean channel. It should be used to equalize the volume between the clean and distortion channel when switching between them. Ch 2 Gain: This is the distortion channel gain control. For the cleanest possible tone, turn the channel 2 Master up all the way and use the channel 2 Gain control as the overall channel volume.
Note that a small amount of noise during rotation of the presence control is normal, and is due to a small DC voltage present on the control. This was deliberately done, in keeping with the "old-style" presence control circuitry that we feel sounds best. Pilot lamp: The pilot lamp lights when power is applied to the amplifier and the power switch is on. The pilot lamp features a screw-on “jewel” that can be removed from the front panel to replace the bulb without having to remove the chassis.
Rear Panel Controls and Switches AC Mains: Plug the supplied IEC mains cord into this outlet to provide power to the amplifier. Mains Fuse: 2A slo-blo for 100V/120V operation, 1A slo-blo for 200V-240V operation. AC Mains voltage selector: Set this switch to the appropriate position to match the mains voltage in the country in which you are using the amplifier.
Bias Test Jacks: Three standard tip jacks are available to allow easy bias current measurements without removing the chassis. Refer to the section on biasing for instructions on the use of these jacks. Bias control: A locking mil-style RV6 trimpot is provided to allow adjustment of bias current. The outer locknut must be loosened before adjusting the screwdriver-slot control. Refer to the section on biasing for further instructions. Effects Loops: This is a 1/4" TRS (tip/ring/sleeve) insert style jack.
For more information on programming the G-Major relay function, refer to the TC Electronics manual*. Aiken Amplification is in no way affiliated with TC Electronics, we just were told about this effects unit from a customer, and decided that it looked like it was tailor-made for use with the Sabre! * Footswitch jack: This is a 1/4" TRS (tip/ring/sleeve) insert style jack.
Tube layout and replacement The Sabre uses five 12AX7/ECC83 tubes and EL34. The preamp tube function is as follows, starting at the side closest to the input jack: CH1 preamp 1/CH2 preamp 1 (12AX7/ECC83), CH1 effects recovery amp/CH2 preamp 2 (12AX7/ECC83), CH2 preamp 3/CH2 preamp 4 (12AX7/ECC83), CH2 effects recovery amp/CH2 cathode follower (12AX7/ECC83), and phase inverter(12AX7/ECC83). The chassis top view layout is shown in the diagram above.
Biasing Biasing is very easy, and doesn't require removing the chassis from the cabinet. You simply use a voltmeter (any inexpensive digital multimeter will do), set it for the smallest DC voltage range (typically 200mV). Then: (1) Unplug any guitar cords going into the input jack. Turn the two volume controls all the way down (other control positions don’t matter). Unscrew the lock nut on the bias pot on the rear panel, and turn the bias control all the way down (counterclockwise).
Speakers Changing speakers is like getting a whole new amp. Every model sounds completely different, some sounding quite good and some amazingly bad. The amplifier is particularly suited for use with Celestion loudspeakers, which give the characteristic "British" sound this amplifier is designed to create. Celestion Greenbacks have less volume and a dip in the mids, which makes them nice and smooth. The amplifier was voiced for this speaker in a 4x12 cabinet or a 2x12 cabinet.
Troubleshooting Pilot lamp not lit: Is the amplifier plugged into a functional outlet of the appropriate voltage? Is the mains fuse blown? If so, replace with the appropriately rated fuse. If the fuse again blows, the amplifier may have a shorted output tube or rectifier tube. Replace the tubes and fuse, and power the amplifier up again. If the fuse still blows, the amplifier will need to be serviced.
Humming or buzzing noise: Unplug the guitar cord from the input and unplug any cable used for jumpering the two inputs. If the buzzing stops, try replacing the cord. Be sure to use only guitar cables, not unshielded speaker cables! If in doubt, unscrew the connector and look to see if there is a shield around the center connector. Some smaller speaker cables are easily mistaken for guitar cables. Fluorescent lights and light dimmers can be a source of hum/buzz, as can computer monitors.
"Ticking" noise: Some tubes (particularly JJ ECC83) tend to exhibit a low-level "ticking" noise right after the amplifier is taken off standby. The noise stops after a second or two, when the tube has had a chance to stabilize, and is not indicative of a problem.
(2) If the mains fuse blows immediately upon power up, you likely have blown rectifier diodes. These can easily be replaced by any competent technician. They are located in the upper right corner of the chassis, below the voltage selector and mains fuse, mounted on blue standoffs (when replacing the diodes, be careful not to to break these standoffs. It is best to carefully cut the diodes out, then unsolder the leads to avoid stressing the standoff).
Specifications Output Power: 50W RMS at onset of clipping into resistive load at rated impedance. Input Impedance: 1 Megohm Input sensitivity: < 1mV for full clipping, channel 2 Tube complement: Five 12AX7/ECC83 preamp tubes, two EL34 power tubes. Fuses: 100V-120V: Mains: 2A slo-blo, HT: 500mA fast-acting 200V-240V: Mains: 1A slo-blo, HT: 500mA fast-acting Dimensions: Head: 25.5" W x 10.
