The ED111 Active Busboard is a member of our performance family of busboards and power supply solutions for modular synthesiser systems.

The ED111 strives to provide a high-quality DC power distribution system offering low-noise module power outputs and minimal bleed-through.The ED111 comprises 12 power module zones each with its own dedicated pair of linear regulators that deliver the low-noise performance expected by audio and synthesiser users.Power for the ED111 is derived from an external DC power supply with a nominal voltage rating of 15VDC. This supply directly feeds the positive rail regulators as well as powering a small SMPS module that generates a -15V rail for feeding the negative regulators.

The ED111 thus provides:-

The maximum total loading on the -12V rail for each ED111 is around 700mA. A system using multiple ED111s, will, therefore, provide n x 700mA, where n equals the number of ED111s in the system.

To determine the current capacity of the external supply, sum the +12V and -12V loading for all modules, add 100mA for each ED111 and then multiply by 1.25. So, for example, if your system has 1 x ED111, a total draw on the +12V rail of 1.2A and a total draw on the -12V of 400mA then the calculation for the external supply rating would be:-

total_loading = total_draw * 1,25
= (1.2A + 400mA + 100mA) * 1.25
= 1.7A x 1.25 = 2.13A

So the optimum rating would be 15VDC @ 2.2A. A larger capacity supply can be used but ideally, the maximum rating should be kept to less than 2 x total_loading or 4.4A in this example.

No allowance is made in these calculations for a 5V module supply. If you use one of the 12V-5V adaptors then you should add a 5V_loading figure to your total_draw where: 5V_loading = (total current draw on the 5V rail) * 0.42

Dimensions
The ED111 has dimensions of 205mm x 101mm which allows it to comfortably occupy a 3U 42HP section of your system. Builders may, therefore, optimise the size of the distribution system by determining how and where they require module power and selecting the appropriate number of ED111s to satisfy that need and any predicted future expansion.

Active and/or Passive?
The main intent of the ED111 is to provide a set of quality power outputs offering both low-noise and minimal inter-module interference. Typically it would be expected that sensitive modules such as VCOs would be connected to the ED111. It may be felt that other, more general purpose modules such as ADSRs may not need the performance capabilities offered by the ED111 and wish to power these from a more conventional distribution system. This is readily achieved by expanding the system with our ED705 Powered Busboard and, optionally, our ED704 Busboard (note you must have at least 1 x ED705 in the system to generate the +/-12V required to be distributed via the passive busboards).

Readers are advised to read our document DC Distribution Systems which talks about the various busboard systems and includes suggested system configurations.

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