Description
Robertson Audio Forty Ten 2 — A Focused Stereo Power Amplifier
The Forty Ten 2 is a dedicated power amplifier for listeners building a system around separate source, preamplifier and speaker components. Its low-profile case, substantial rear heatsinks and uncluttered front panel reflect a straightforward approach: source selection and volume control take place upstream, leaving this unit to provide the amplification for your loudspeakers.
Power and Circuit Design
The Forty Ten 2 uses a Class AB, semi-dual-mono circuit layout, with published rated output of 75 watts per channel into 8 ohms and 145 watts per channel into 4 ohms. The increase into the lower impedance is useful when considering speaker matching, although the speakers’ sensitivity and impedance curve, room size and listening level also matter.
The semi-dual-mono arrangement uses a single shared transformer with separate capacitor supply rails for the left and right channels. Large external heatsinks at the rear provide cooling without taking up space on the front panel. Position the amplifier with adequate ventilation and leave the heatsink fins unobstructed.
Connections and System Matching
- Unbalanced stereo RCA inputs: one socket per channel for connection to a suitable preamplifier.
- Speaker binding posts: separate positive and negative terminals for the left and right speakers.
- External volume control required: use a conventional preamplifier or a compatible DAC/streamer with a variable analogue output. A fixed-output source needs a preamplifier between it and the power amplifier.
- Simple front-panel operation: a power switch keeps day-to-day operation straightforward; input switching and volume adjustment are handled by the connected control unit.
- Detachable mains connection: rear IEC inlet, alongside accessible mains and channel fuse holders.
Condition and Testing
This amplifier is A3 condition, with minor marks on the top panel, and has been checked and tested by Andrew. The photographs show the actual item, including its cosmetic condition. Stock reference: 8806.
Why Buy From Us?
- 3-month guarantee and a clear description of the actual equipment, offering reassurance beyond an unverified marketplace purchase.
- Over 40 years of experience selling second-hand hi-fi, with advice on system matching and after-sales support by phone or email.
- Competitive pricing with typical eBay-style marketplace asking prices in mind.
- Secure packaging to protect the amplifier during delivery.
Forty Ten 2 Technical Details
- Manufacturer: Robertson Audio.
- Model: Forty Ten 2; rear-panel designation Forty-Ten2.
- Amplifier type: stereo power amplifier.
- Operating class: Class AB.
- Circuit layout: semi-dual-mono, with one shared transformer and separate capacitor supply rails for each channel.
- Published output into 8 ohms: 75 watts per channel.
- Published output into 4 ohms: 145 watts per channel.
- Audio inputs: 2 RCA sockets, left and right.
- Speaker outputs: binding posts for one stereo pair of speakers.
- Cooling: external rear heatsinks.
- Mains connection: IEC inlet.
- Country of manufacture: Singapore, as marked on the rear panel.
Power ratings above are published figures for the Forty Ten 2; they are not bench measurements taken during our checks.
