Common Features of
London Power Amplifiers

London Power's instrument amplifiers are built in a 4U (7", 176mm high) rack-mountable chassis, except for AURORA, SILHOUETTE, STUDIO-10 and 3-D tube reverb, which are 2U (3.5", 88mm high). The amps can easily be mounted in an amp sleeve to be used in a "head" configuration. The STUDIO-PREAMP and ICON preamp are 4U (7", 176mm high).

All amps and accessories have world-wide mains compatibility. Manual range selection in the AURORA, SILHOUETTE, STUDIO-10 and 3-D and automatic mains range selection in the other units allow accommodation of any mains from 100V to 250V in two ranges.

In the 4U amplifiers, all tubes are accessible from the front by removal of a vent cover even while the amp is still in the rack or amp sleeve. Bias adjustments and meter jacks are also accessed via the vent cover. Tube access for the AURORA and STUDIO-10 is via a rear panel vent cover for power tubes, or by way of top cover removal for preamp tubes. Bias adjustments and meter jacks are on the rear panel. Tube access in the 2U and 3U preamps/accessories is by way of the top cover or a rear vent. The bias procedure is in the amp owner's manual. Preamp tubes do not require biasing.

The range of "tone" amps for creating new and traditional guitar, bass or keyboard sounds include: STUDIO-10, STUDIO POWER AMP, STUDIO SYSTEM (the STUDIO POWER AMP + STUDIO PREAMP), SUSTAINOR, AURORA and RAVEN.

The range of "boost" amplifiers includes the SUPER SCALER. SUPER SCALER requires power input to produce power output, and must be driven from the speaker output of a tone amp.

All tone amps accept any combination of the following tubes: 12AT7, 12AU7, 12AX7, 12AY7, 12AZ7, E81CC, E82CC, E83CC, ECC-81, ECC-82, ECC-83, 6CA7, 6L6G, 6L6GB, 6L6GC, 6V6, 6V6GT, 5881, 6550A, 6550B, 6550C, E34L, EL-34, KT-66, KT-77, KT-88, or any variants. Tone amps can operate with one or two power tubes in place.

All boost amps accept any pair of the following power tubes: 6CA7, 6L6G, 6L6GB, 6L6GC, 6V6, 6V6GT, 5881, 6550A, 6550B, 6550C, 7591A, E34L, EL-34, KT-66, KT-77, KT-88, or any variants. Ideal performance is attained with two tubes of the same type, but dissimilar tubes can be employed.

ICON and STUDIO PREAMP accept any combination of the folllowing tubes: 12AT7, 12AU7, 12AX7, 12AY7, 12AZ7, E81CC, E82CC, E83CC, ECC-81, ECC-82, ECC-83, or their equivalents.

3-D provides optimal performance when fitted with its factory configuration of tubes, comprised of 12AU7s, 12AT7 and 12AX7.

All tone amps can be operated as 0-25W push-pull, switchable to 0-5W single-ended, except for STUDIO-10 which is 0-10W PP and 0-2W SE, and RAVEN which is 0-50W PP and 0-5W SE. In both modes, the BODY control adds warmth. SUSTAINOR and STUDIO POWER AMP are each two complete amplifiers, as 0-25W PP switchable to 0-5W SE. STUDIO POWER AMP has dual BODY controls for bidirectional single-ended access.

Super Scaler is 0-300W.

All products use custom toroidal power transformers with two levels of noise shielding and world-wide mains compatibility. Tone and Boost amps use custom shielded toroidal output transformers. Selected transformers are used for ground isolation of effects send and return lines, line inputs and line outputs. All products use low-noise metal-film resistors, with flameproof metal-oxide types in power positions. All capacitors are high-reliability types selected for their specific circuit locations. Tube sockets are ceramic for long life. STUDIO-10 uses multiple choke filtering where all other models use active hum-filtering circuitry. High-quality printed circuit boards use twice the industry standard copper weight to assure longevity against vibration. PCB configurations are designed to streamline servicing.

2-U chassis are stainless steel. 4U chassis are heavy-guage aluminum alloy, with anodized side panels and clear alodined top, bottom, rear and internal panels. Alodining assures resistance to corrosion while providing electrical conductivity similar to copper. London Power's Galactic Ground scheme is implemented, and the chassis is used purely for shielding. Ground-lift switches are provided for every input and output equipped with an isolation transformer, and there is also an over-all ground lift. The chassis is always tied to the safety ground, and a three-wire AC mains cord must be used at all times.

The 3-D tube reverb uses a proprietary push-pull drive circuit and custom transformer for very clean signal into the full-length Accutronics custom delay line.

The STAGE LINK amp switching accessory is powered from any of the tone amps it operates with, including:RAVEN, SUSTAINOR, STUDIO POWER AMP and STUDIO SYSTEM.

All units have a Five Year Warranty for all components, except for: tubes; and the delay line in the 3-D. Units shipped to us for warranty repair will have one-way return shipping covered by the warranty.

Other helpful pages:

• London Power Tube Amplifiers and Accessories

• Amp Pricing and Ordering Info

• Selecting a London Power Instrument Amplifier

• Power Scaling Q&A
• Super Scaling Q&A
• Effects Loop Truths

And also:
• Coolohm Products

And even:
• Back Shop - Unique Values

---