Doepfer

Thanks Dieter,

there has been some discussion about this over on the electro-music
forum where the consensus is that, in a modular environment, switching
supplies are less than satisfactory and linear supplies are the only
way to go. Do you mind if I quote your message on other forums or
could you perhaps put this information on the web site in the DIY section?

Cheers,
Adam-V
--- In Doepfer_a100@yahoogroups.com, <hardware@...> wrote:
>
> Dear members,
> 
> I just wanted to inform you about the results of our tests with several
> switching power supplies for A-100. The main advantages of switching
power
> supplies are the wide range AC input (typ. 90-240V AC, i.e. no supply
> modification if you move e.g. from USA to Europe and vice versa),
low price
> and small shape/weight. As some customers suggested switching
supplies we
> ordered three types of these supplies (Meanwell, Sun Power,
Condor/SL) and
> installed them into standard 6U cases and a monster case.
> 
> For all tested supplies the results are very poor. The main problem
is the
> unsufficient load regulation that may lead to VCO tuning problems.
We found
> up to 200 mV (=0.2 V) voltage change of the +/-12V supplies while
the load
> changes. Such load changes are caused e.g. by different LED
illuminations
> (normally a module will consume more current if a LEDs is bright
compared to
> the dark state) or other effects (e.g. frequency changes of
VCO/VCF). For
> the linear A-100PSU2 the +/-12V changed only by about 5mV under the same
> conditions. Consequently switching power supplies can be recommended
only
> for "non-critical" DIY applications (e.g. if only CV
sources/modifiers and
> audio modifiers are installed). For frames that include one or more
VCOs we
> recommend the A-100PSU2 or another linear supply with good load
regulation
> (10 mV or better).
> 
> I hope this information will help some DIYers.
> 
> Best wishes
> Dieter Doepfer
>