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3CP1 (2002)


3CP1 was the name of the amplifier first released by Peters Amplification in 2002. It was a medium/high gain single-channel amplifier with a classic British feel and tone. There was only one output power configuration for the original 3CP1 model, approximately 10W (SE class A), using one power tube and two 12AX7 preamp tubes. These original 3CP1 models accepted 6V6, EL34, and 6L6 tubes, having been designed somewhat down the middle for those three tube types. There is no bias adjustment required for different output tubes (the amplifier is self-biasing).

Version 1.5 of the 3CP1 was later released (indicated on the back of some units made later in 2002), with a slight change in the preamp circuitry. It was made to sound more woody/open, and had less preamp gain.

The main controls are low, mid, high, gain and master volume.

All 3CP1 amps have a boost switch on the front panel which increases the overdrive.

Some units have edge switches which give an upper mid emphasis for a bit more aggression.

A few 3CP1 amps had a series effects loop installed in place of the edge switch. These used tip-ring-sleeve jacks so a stereo insert cable is required for use. (Tip end = send, ring end = return, stereo end goes into effects jack.) This is a basic series preamp out / poweramp in type of effects loop best suited to rack effects. Some pedals will still function well in this loop, depending on their design (generally speaking, this loop is not suitable for most pedals for anything other than lower to moderate volume levels).

For impedance matching, see the engraving on the back of the amp. There are markings above and below the output jacks indicating which impedance to use for each basic output tube type.

Fuse and lamp bulb ratings

Mains: 2A slo-blo

H.T.: 1/8A (0.125A) slo-blo

Both fuses should be rated for 250V.

Lamp bulbs are 117V / 25mA (3W or lower) for most units. Units marked with version 1.5 below the serial number, as well as units with the following serial numbers require lamp bulbs rated for 6.3V / 150mA (0.95W):



Later units were made to accommodate the more commonly available 6.3V bulbs for convenience. The two 3CP1 amps with serial numbers listed above were changed to the 6.3V lamp arrangement without modifying them to version 1.5 specs.

Note: The 2004 3CP1 model isn’t a re-issue or re-release of this 2002 3CP1 design. It was a new design meant for a more bold/woody sound, had more low end/depth/headroom, and was specifically designed for larger octal tubes (EL34, 6L6, KT66) to get the most those tubes have to offer tonally. The 2004 3CP1 model is easy to tell from the 2002 model since it’s an overall smaller size.