As far as I know there is only one module in the Doepfer lineup that requires a separate +5V supply and that is the MIDI>CV converter. Of all the manufacturers out there I think that Analogue Solutions and Analog Systems are the only companies in the eurorack format that require a separate +5v signal - all the digital modules I know of convert the +12V to +5 on the module so the "not supporting the +5V rail" is a industry trend and not just something Doepfer is doing. What Digital modules out there would use this separate +5V line if there was one Is the Digital ground>Analog ground a real problem on the modules that do convert it onboard. I assume it is isolated on them. I think the major problem is that the digital modules that do convert the +12v make an extra load for that side of the supply. More should convert from the -12v supply to balance it out. There are very few modules that even offer an option to choose to use the +5v supply bus - IIRC Scott Harvestman said he once offered a jumper option on one of his modules and nobody used it so he discontinued it. Until the module makers all convert over to using the +5v bus there is no reason to burden the rest of the non-digital users with the expense of a separate supply.
-James

**Disclaimer** As you can see from my sig I design for Synthwerks and have to disclose that we make a module (the PC5V) that converts the +12v supply to +5v and pipes it to the bus (and front panel with a level control. I have to admit it is not a big seller for these reasons. There seems to be a lot of modules that require it.


James Husted
Designer, Synthwerks LLC
www.synthwerks.com
james@...
synthwerks@...

On Nov 9, 2010, at 1:31 PM, Joachim wrote:

> Hello there,
>
> there is currently a lot of talk going on about Doepfer not supporting
> the +5V rail with the standard housings. Here is the thread:
> http://www.muffwiggler.com/forum/viewtopic.php t=24399
>
> Short summary:
>
> a. There is definitely a demand that the power supply in the standard
> housings supports +5V
> b. +5V is used for digital modules and therefore should have a separate
> digital ground on the whole way (module => cable => bus board => power
> supply) to avoid digital noise coming over the common ground.
>
> Necessary steps:
>
> For a:
> 1. Using either tri output power supplies like the ready-made Meanwell
> T-60C or an additional 5V power supply, e.g. the Meanwell S-25-5 with
> 5,0A of +5V. Meanwell is just an example, there are several other
> manufacturers like Power One and a current transformer with
> +5V/+12V/-12V outputs could be used, too, of course.
>
> For b:
> 2. Change the specification for the power connection so that one of the
> three ground lines is reserved for the digital ground while the other
> two remain for the analog ground. It would still be compatible to the
> old specification with the downside of more noise which is what happens
> at the moment anyway when the +5V is taken from the +12V rail without a
> separate digital ground.
> 3. Change the bus boards to implement the separate digital ground.
> 4. Change the existing +5V modules to make use of the separate digital
> ground.
>
> While we are at the subject of a bus board change: There is a big demand
> for keyed connectors, too. They would help to avoid wrong connections
> for modules which use the specification, force the manufactures who are
> ignoring the key position specification to support it and help to
> connect the modules which is currently a pain in the a**.
> I myself would gladly pay the slightly higher price for keyed connector
> bus boards.
>
> Cheers
> Joachim
>
>
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