VS-10 Voltage Stage module
With this VS-10 Voltage Stage (input) module we provide the most cost effective input module we have. We normally use it in cost-effective and high power models with Hexfets, which are very rugged and so most suitable for PA-applications.
We arranged this VS-10 module in a way, that you can select the Power Supply voltage range from ±20-65V or ±60-100Vdc by setting of two jumpers. Doing so, you can decide to use it in some smaller, cost effective applications in a voltage range of 20-63V. For high power applications you can remove the jumpers and so set it at 100V, where amplifiers with serious output power up to 2000 Wrms (2kW) could be built. But then you need more than just a CS- and a VS-module!
VS-10 Voltage Stage (input module)
While using more or less "basic" components this input module is cost effective. The mirror input stage is based on 4 regular SMD transistors. Positioned exactly in the middle at the backside of the PCB close to each other the temperature (drift) is very low and the same for all, making it at stable amplifier, regardless it's temperature. Just by mounting them the right way at the right place. NO extra electronics for compensation of the drift required. All the symmetrical connected parts have exactly the same track lenghts and in a mirrored position. The driving transistors for the CS-board are quite regular, yet low-noise, high voltage TO-126 type transistors.
The frequency limiting RC-network is using a regular, yet MKP type of capacitor. All resistors are 1% Metal Oxide Film (MOX) resistors. The PCB tracks on this double sided FR4 board have a thickness of 18um (VS-20 is 35um).
At the left and right connector, the power supply voltages are available for extra add-on modules and there is an AC- and DC input, where the PCB mounted MKT capacitor is bypassed. You could use this input if you want to drive the amp from DC on, but then you have to be sure that the preceeding device is totally free from a DC-offset, f.e. due to the output capacitor this device most probably already has. You could also decide to use the DCin and add a, mostly large, input capacitor of a type/brand you want. Just a matter of taste, space and wallet.
We were able to develop the PCB in a way that the inputs and their required parts can be mounted either left or right, so the inputs will always be as close as possible to the input connector. Here, the input is shown at the left side, in the VS-20 it's shown at the right side.
In a similar way, the DC-offset trimming parts (blue multi-turn trimpotmeter) can be mounted at the opposite side.
We can decide to mount an angled mid-connector (normally used, see VS-20) at the front, mounting this VS-10 board L-mounted to a CS-board or, as in this picture mount a straight connector at the back. In that case we become a "sandwich" construction with lowest possible total height (32mm) in the LP versions (See chapter 4). Due to the fact that the PCB tracks come closer to the CS-module tracks, you will loose some of the quality though.
VS-10S on CS-40ps VS-10L on CS-80
If costs are the deciding factor, you could first mount this module and exchange it at any time by a VS-20 module. In that case and at voltages >63V, you will also need a Voltage Regulator board, bringing down the Power Supply voltage to around ±30V for this board only.
The alignment procedure of a CS/VS pack is most simple and can be downloaded from our parts website.