Yahoo !
I got it : ferrite.
I replaced the long RCA cable by a shorter one thru a ferrite ... and
it works better than well : terrificaly well.
Hum noise almost desappeared : I reach distortion before I can ear it.
Summary :
1/ change springs unit position
2/ replace RCA cable by a shorter one thru a ferrite
NB : I took my ferrite appart from a no longer used hard drive power cord.
Cheeerrs 'o'
--- In Doepfer_a100@yahoogroups.com, "pfichoux" <pfichoux@...> wrote:
>
> Looks like the power supply is new-style.
>
> Furthermore, there is not enough space to mount the spring not in
> parallel to the frame.
>
> I'm now thinking to a ground problem : I tried with the springs unit
> outside the suitcase : noise changes when I touch the RCA cable
> anywhere between the module and the springs unit.
>
> Perhaps a solenoid would filter 50Hz ?
>
> --- In Doepfer_a100@yahoogroups.com, Florian Anwander
> <Florian.Anwander@> wrote:
> >
> > Hi
> >
> > if the suitcase has an old-style transformer (rectangular) it might
> make
> > sense to mount the spring not in a parallel direction to the
frame. You
> > may have to try a satisfying position by testing. Also you should
obey,
> > that not only the transformer will cause some hum. Also (neon or
> > halogene) lights, powercables or wallwarts outside the doepfer
case may
> > induce the hum to the coils of the springreverb.
> >
> > Florian
> >
> > pfichoux wrote:
> >
> > > I was disappointed by the strong A199 hum noise in my brand new
> Doepfer
> > > A100 suitcase.
> > >
> > >
> > > Perhaps I didn't care enough about Doepfer's home page warning :
> > >
> > > "The spring reverb system is connected to the A-199 module via 2
> cables
> > > with RCA phono connectors. As the reverb system is very sensitive to
> > > magnetic fields it has to be placed in a big distance from the
> > > transformer of the A-100 power supply - privileged in the left upper
> > > corner of the A-100 frame. The reverb system is mounted with
> screws and
> > > nuts or double-faced self-adhesive tape. There has to be sufficient
> > > space for the reverb system (about 20 x 7 x 5 cm).
> > >
> > > For frames that include the A-199 we recommend the usage of the new
> > > power supply PSU2. PSU2 has much less magnetic radiation (because
> of the
> > > ring core transformer) that may cause hum noise in the A-199."
> > >
> > >
> > > Nevertheless, I began to find another position for the A199 reverb
> > > spring.
> > >
> > > Now it is mounted inside the suitcase, on the top/handle side of the
> > > suitcase, open side of the spring reverb unit upwards, with
> double-faced
> > > adhesive tape.
> > >
> > >
> > > Hum noise used to appear with a mix at 8 (9 o clock : almost dry
> > > effect), now I can work easily with a mix at 5:5 (12 o clock).
> > >
> > >
> > > Someday I'll try to build a full shield around the spring unit,
> but I'm
> > > already completely satisfied of my brand new A100 suitcase.
> > >
> > >
> > > Cheers,
> > >
> > > Pierre
> > >
> > >
> > > [Non-text portions of this message have been removed]
> > >
> > >
> > >
> > >
> > > Yahoo! Groups Links
> > >
> > >
> > >
> >
> > --
> > Florian Anwander |ConSol
> > Tel. +49(89)45841-133 |Consulting&Solutions Software GmbH
> > Fax +49(89)45841-111 |Franziskanerstr. 38, D-81669
München
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> > email: florian.anwander@ |http://www.consol.de
> >
>