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Dual Channel (2007/2008)

2007_dc 2008_dc

The 2007/2008 amp format was “50W” with two output tubes, available as single or dual channel models. EL34 was the standard choices for output tubes.

Two looks for the format were available, both pictured above. (The two pictures were taken on different cameras at different times, so colors between the pictures don’t match as they should.)

The format pictured in the top photo measured approximately 26″ W x 9.5″ H x 8.5″ D, and the format pictured in the lower photo measured approximately 25.5″ W x 9.5″ H x 8.5″ D.

Front panel features

Damping: This control changes the overall amount of output damping. Less damping (clockwise) gives a more aggressive/deeper sound while more damping (counterclockwise) gives a softer/mellower sound. This helps tailor the response the amp achieves with different speaker cabinets, or to compensate for different acoustic environments.

Depth: Extra bass response generated by the output section of the amplifier instead of in the preamp. Allows for an extra dimension of bass response tailoring and is especially useful to help attain a “big sound” at lower to moderate volumes. Balancing this control with the Damping, Presence, and preamp’s EQ can allow for more tight/focused sounds or more warm/rich sounds; for instance, turning the channel’s Bass control down and turning the Depth up provides a more rich overall sound without getting very percussive in the low frequencies.

Presence: Extra treble response generated by the output section of the amplifier instead of in the preamp section. Its range starts in the range of a channels’ “High” controls and extends beyond to allow for a sharper overall sound and more treble clarity. This control, along with the “Depth” control, helps shape the overall sound and response of the amplifier to a specific cabinet and acoustic environment. The first 2/3 of the range is gradual, making its setting easy without the amp suddenly becoming bright sounding. The last 1/3 of its range is more drastic a change, for those who want a lot of brightness from the amp.

The above three poweramp controls should be used cooperatively to achieve good balance. For instance if the bass response is too pronounced but you still want the amp to sound warm, turn the Depth up and the Damping down, then turn the presence up to add some extra sharpness if desired (and to the extent you want).

Power indicator lamp: When amplifier is on, this illuminates.

Preamp Low, Mid, High controls: EQ with a very wide range of friendly, useful operation. These controls are shared between the two channels, and are specifically tuned to work properly as a shared EQ (in conjunction with Channel 1’s Bright switch, described below).

Master 1, Master 2: Overall volume controls for the amplifier, one for each channel.

Volume 2, Volume 1: Preamp gain controls for both channels. On single channel models, Volume 1 is for preamp gain and Volume 2 is used as the “master” volume.

“Hot” switches: Each channel has a “hot” switch, indicated by a chili pepper icon. Channel 1’s “hot” switch is located over its Master control, and Channel 2’s “hot” switch is located over its Volume control. These switches change the voicing and feel of the channel’s gain structure.

Bright Switch: Channel 1 (the clean channel) has a switch that increases or decreases its brightness, for contrast with Channel 2 (the overdrive channel). Lower settings of Channel 1’s Volume control are affected more by the bright switch than higher settings; this is so that when Channel 1 is used more as a non-master volume amp, as most vintage clean amps are made (this effect is achieved by turning Channel 1’s Master higher and using its Volume control for overall level), its brightness can be controlled by the Bright switch and by varying the setting of the Volume control. The first third of Channel 1’s Volume control has lots of headroom, so finding a very clean sound with the right degree of brightness to contrast Channel 2’s sound is easy.

Back panel features

Power: On/off switch. Down is off, up is on.

Standby: A secondary “power” switch. First the power switch is turned on, the tubes are allowed to warm up for a minute, then the Standby switch is turned to the “play” position (up). This ensures tube elements reach proper operating temperature before use. When turning the amplifier off, turning off the Standby switch first and waiting 30 seconds before turning the Power switch off ensures no noise from the relay supply discharging and changing channels/masters as the power is removed.

Fuses: The amp’s fuseholders are located above the power and standby switches.

The HT fuse is above the standby switch and the mains fuse is above the power switch.

Fuse ratings (all models in this format are 50W): 2.5A slow-acting (mains), 300mA fast-acting (HT). Both fuses are rated for 250V.

Power inlet: For a standard detachable IEC type power cable.

Effects: Loop for effects (post master volume). Meant for line-level devices. (Will only function properly with instrument-level devices, or pedals at lower to moderate volumes.)

Footswitch: The amp’s footswitch plugs into this jack. A switch beside this jack allows for manual selection of channels when a footswitch isn’t connected. Set the switch to “Channel 1” when the footswitch is connected to allow the footswitch to function. The footswitch’s LED indicates Channel 2 (overdrive channel) being the active channel. The footswitch is an industry standard single-button with LED type.

Speaker Outputs: Five jacks allow for parallel connection of two separate cabinets (at either 8 or 16 ohms each), or a single load of 4, 8 or 16 ohms. Not intended for using loads of different impedances. Choose one overall impedance and connect one or two cabinets for a proper match, as the markings beneath the jacks indicate.

Full Power / Low Power: (2007 functionality) A function to allow the amplifier’s output section to be reduced in power quickly and effectively. “Low Power” is approximately 40% of the amp’s output power rating. (2008 functionality) Subtly changes the response of the amplifier in terms of its power supply to provide a more “normal” (focused) or a more “wide” (broad) responsiveness.

Modern / Vintage: This feature gives the amp’s output some “sag” normally characteristic of using a tube rectifier in a design, but without requiring a tube rectifier. “Modern” has a more forward/punchy sound/feel, while “Vintage” has a warmer more relaxed sound/feel with less “forward” sounding midrange.

Bias test points and bias adjust: Using a regular volt meter and small screwdriver, the amp can be biased for replacement output tubes quickly and easily without opening the amplifier. There is a small access hole for the easy-to-adjust 15-turn bias potentiometer and to its right, three pin jacks for testing the bias setting during adjustment. The two red jacks represent each tube’s “positive” reading point and the “common” reading point in the middle is black. For instructions of biasing Peters amplifiers, read this document.

All dual channel models in this format had the HALO as their “clean” channel.