Features
| Warranty length | 2 Years |
|---|---|
| Brand | Cary Audio |
Tech Specs
- Input Impedance - 100K both RCA and Balanced
- Frequency Response - 17 Hz – 25 KHz flat @ 1 watt
- Tubes - 2 – 6SN7 input gain stage, 2 – 6SN7 driver tubes, 8 – KT 88 output tubes
- Power Supply Capacitors - 4 x 560µF
- AC Power Requirements - 117 VAC @ 50/60 Hz, 234 VAC @ 50/60 Hz
- Warm-Up Time - 3 Minutes
- Weight - 65 lbs
- Dimensions - 8″ H x 17 ” W x 14″ D
Product Description
The Cary Audio CAD-120S MkII Valve Power Amplifier is a valve amplifier that can operate in triode mode or Ultra linear mode. Just flick the front panel switch. Ultra-linear mode provides 120 watts per channel, while Triode mode gives 80 watts per channel. Inputs are via a couple of RCA sockets.
Also, there is also a balanced XLR input for enhanced noise performance. This new MK II version has boosted sensitivity and reduced feedback. Therefore you can now use a wider range of Preamps. The front panel features two meters that monitor the output stage bias. Notably four KT88 valves are used in the output stage.
Triode or Ultra linear mode
Notably, the Cary Audio CAD-120S MkII Valve Power Amplifier is a valve amplifier that can operate in triode or ultra-linear mode. In triode mode, the output valves are operated as Class A. This provides the lowest possible distortion and more detail in the music.
The output power, however, is lower. Ultra-linear mode switches the unit to Class AB. Class AB provides more power and dynamics. In some cases, it can also have less distortion, than even Class A. Two meters are provided to monitor the output bias.
Exemplary Build quality
It is a very labour-intensive process. As a result, PCBs started to be used, from the 1960’s onwards. However, they are not ideal for valve circuits. Valves tend to get hot and cause the soldered joints to fail, over time.
Additionally, the boards start to blacken and buckle with the heat. Hence the best modern units use point-to-point wiring. Next, the output transformers need to be carefully designed and manufactured. Notably, modern methods of construction and modern materials provide superior performance compared to the older types of transformers.
Output transformers are needed as the output impedance of valve circuits is too high to apply to a speaker directly. Moreover, there is a high voltage present. The transformer's speaker winding prevents this high voltage from being present on the speaker terminals of the amplifier.
Connectivity
Notably, The Cary Audio CAD-120S MkII Valve Power Amplifier is designed to be used with a preamp as there is no volume control. The input consists of two RCA connectors. Moreover, there is a balanced XLR input that can be used to reduce noise pickup on the connecting cables. Lastly, the front panel is kept clean with just the on/off and mode selector switches.
Additionally, two meters monitor the output stage bias. This enables the output stage operating conditions to be viewed. Output bias is important as too high a current can damage the expensive output valves. This is described as red-plating.
Valve thermionic technology
Valves use a heated cathode to generate a flow of electrons. This is known as thermionic technology. Triode valves have been around since 1908 and they were the first device that could amplify electrical signals. Most types of valves have three basic electrodes, the cathode, anode, and grid.
There is also a heater that normally runs at 6.3 Volts. The anode has a high voltage placed on it. This attracts electrons from the cathode, setting up a current flow. Between the two electrodes, a control grid is kept slightly negative of the cathode. This grid bias sets the operating conditions for the valve. Additionally, the audio signal is applied to the grid, via a capacitor. An amplified version appears at the output.
