Here's an option: make a power connector on the panel FRONT and include a wall wart
that can supply the 6v (AC or DC) for the tube heaters.

The wall wart can be cheap since I assume it doesn't have to be regulated. You can still
provide internal connections for those willing to wire up another PS themselves. The front
panel can have an additional connection for daisy-chaining the heater voltage to
additional modules.

This option could now allow every Erro and Frac user to easily add your cool tube modules
to their systems.

--- In Doepfer_a100@yahoogroups.com , "metasonix2000" <synth@...> wrote:
>
> > i don't currently use the 5v for any of my modules. if my memory
> > serves correctly, there is one rail used by the full-sized 16-pin
> > (opposed to the 10 of 8 pin) connector that carries +5vDC as needed,
> yes
>
> Right. However....if you mount 3 of these modules in a Doepfer
> rack, that will add up to perhaps 1800 mA of load. That might
> be better delivered by separate wiring, although I think the
> existing 16-pin power busses should be able to handle a couple
> tube modules.
>
> NOW, do you see why there are no tube Euro modules
>
> It's POSSIBLE to use +-12v only. It requires the usage of
> tubes with 12v or other "odd" heater voltages, which are
> easy to get but not as commonplace as 6-volt heater versions.
>
> (I'd like to use 6GH8s if at ALL possible. At one time,
> the 6GH8 was the one tube in the world manufactured in
> the largest quantities---
> mainly because it was used in TV sets that ran them
> very hard, and made for a short lifetime.
> Lud Sibley of the Tube Collector's Association owns the
> RCA corporate archive. He did the research in the files
> and found that in 1960-61, RCA was making FOUR MILLION
> 6GH8s PER MONTH. By comparison, they made "only" about
> 100,000 12AX7s per month. So, leftover 6GH8s are
> everywhere today.)
>
> And the total power consumption will be the same anyway.
> A typical two-tube module will use about 3-4 watts just
> for tube heaters, regardless of where the power comes from.
> So it's your choice:
>
> 1) get the cab modified to hold an extra +5v supply,
> or
> 2) use large +-12 power supplies to run the tube load.
>
> And there's another headache:
> Want a Frac version of these modules Well, Frac systems
> usually have +-15v. No problem for the solid-state support
> circuits. But the tube heaters will HAVE to have optional
> dropping resistors to keep their voltages down.
>
> More complexity, more PC board space.
>