Doepfer

Hi gang - 

I have a 6U case and a 9U case, the 9U PSU hums (which changes in frequency when different modules are in use.) - the 6U does not do this.... is this ok?

Is it the torrid ring type (version 2) or the older black box type?   My old black box version 1 PSUs used to hum, but I've upgraded now.

Nick


On Jul 6, 2013, at 6:31 PM, "isoldeandisobelle" <isoldeisobelle@gmail.com> wrote:

> Hi gang - 
> 
> I have a 6U case and a 9U case, the 9U PSU hums (which changes in frequency when different modules are in use.) - the 6U does not do this.... is this ok?
> 
> 


[Non-text portions of this message have been removed]

It is version 2.
--- In Doepfer_a100@yahoogroups.com, Nicholas Keller <maq163x2@...> wrote:

>
> Is it the torrid ring type (version 2) or the older black box type?   My old black box version 1 PSUs used to hum, but I've upgraded now.
> 
> Nick
> 
> 
> On Jul 6, 2013, at 6:31 PM, "isoldeandisobelle" <isoldeisobelle@...> wrote:
> 
> > Hi gang - 
> > 
> > I have a 6U case and a 9U case, the 9U PSU hums (which changes in frequency when different modules are in use.) - the 6U does not do this.... is this ok?
> > 
> > 
> 
> 
> [Non-text portions of this message have been removed]
>

Sorry, I don't know what to suggest.  Hopefully Dieter will respond.  There is a ground wire that attaches to the case itself, is that connected?  I don't think that is the problem, but you should make sure it is connected.  

If you bought this stuff new, you should contact Doepfer directly.




On Jul 6, 2013, at 11:26 PM, "isoldeandisobelle" <isoldeisobelle@gmail.com> wrote:

> 
> It is version 2.
> --- In Doepfer_a100@yahoogroups.com, Nicholas Keller <maq163x2@...> wrote:
> >
> > Is it the torrid ring type (version 2) or the older black box type? My old black box version 1 PSUs used to hum, but I've upgraded now.
> > 
> > Nick
> > 
> > 
> > On Jul 6, 2013, at 6:31 PM, "isoldeandisobelle" <isoldeisobelle@...> wrote:
> > 
> > > Hi gang - 
> > > 
> > > I have a 6U case and a 9U case, the 9U PSU hums (which changes in frequency when different modules are in use.) - the 6U does not do this.... is this ok?
> > > 
> > > 
> > 
> > 
> > [Non-text portions of this message have been removed]
> >
> 
> 


[Non-text portions of this message have been removed]

Hi - Thank you both for your replies.

I am not sure what you mean by ''mechanical'' but, the sound is coming from the transformer itself. It is not too loud but I can hear it from a short distance away. The earth cables are all connected properly. My other 6U case is connected to the exact same power supply and makes no noise - this is what concerned me

--- In Doepfer_a100@yahoogroups.com, Florian Anwander <fanwander@...> wrote:

>
> Hello
> 
> I assume you mean a mechanical hum. Right?  If so, then it should be 
> related to the method how the powersupply is fixed to the housing.
> 
> Florian
> 
> 
> On 07.07.13 00:31 , isoldeandisobelle wrote:
> > Hi gang -
> >
> > I have a 6U case and a 9U case, the 9U PSU hums (which changes in frequency when different modules are in use.) - the 6U does not do this.... is this ok?
> >
> >
> >
> > ------------------------------------
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
>

I think all coil based voltage transformers will emit noise. It is often due the coils attracting and repelling one another at each voltage cycle change.

Winding them tightly helps initially but the coils  lengthen as they age and they loosen up. Varnish helps delay the loosening by binding the coils.

Is the hum mains frequency matched?

That would indicate that the above case is likely.

I have only known solid state transformers not to hum.

i would mount the PSU boards on Rubber washers to minimise making the case a sound box.

Any concurrance?

Regards Anoop
--- In Doepfer_a100@yahoogroups.com, "isoldeandisobelle" <isoldeisobelle@...> wrote:

>
> Hi - Thank you both for your replies.
> 
> I am not sure what you mean by ''mechanical'' but, the sound is coming from the transformer itself. It is not too loud but I can hear it from a short distance away. The earth cables are all connected properly. My other 6U case is connected to the exact same power supply and makes no noise - this is what concerned me
> 
> --- In Doepfer_a100@yahoogroups.com, Florian Anwander <fanwander@> wrote:
> >
> > Hello
> > 
> > I assume you mean a mechanical hum. Right?  If so, then it should be 
> > related to the method how the powersupply is fixed to the housing.
> > 
> > Florian
> > 
> > 
> > On 07.07.13 00:31 , isoldeandisobelle wrote:
> > > Hi gang -
> > >
> > > I have a 6U case and a 9U case, the 9U PSU hums (which changes in frequency when different modules are in use.) - the 6U does not do this.... is this ok?
> > >
> > >
> > >
> > > ------------------------------------
> > >
> > > Yahoo! Groups Links
> > >
> > >
> > >
> > >
> >
>

Hello

I assume you mean a mechanical hum. Right?  If so, then it should be 
related to the method how the powersupply is fixed to the housing.

Florian

On 07.07.13 00:31 , isoldeandisobelle wrote:
> Hi gang -
>
> I have a 6U case and a 9U case, the 9U PSU hums (which changes in frequency when different modules are in use.) - the 6U does not do this.... is this ok?
>
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>
>

Thank you very much to you both for your help.

I earlier removed a module from the 6U case and put my ear has close to the transformer has I dare, and yes, there is a slight hum being emitted, only slight and barely noticeable. I have had this case for some time and have never had a problem with it at all.
I received this new 9U case only last week and it is empty but for a few modules - perhaps the larger size and the fact that it is empty, is just making it seem to amplify the normal operational sound of the transformer.
I have had it on for some period and there is no abnormal operation with the modules - certainly no static, etc coming from the module face plates... the only thing beside the sound that I have noticed is, that when switched off the bus board led's take a few seconds to dim to off, whereas with the 6U they dim instantly when the case is powered off.

Reading elsewhere, I have noticed that others have experienced similar and the solution was to perhaps mount the PSU on rubber washers and the like - but, it really is not such a problem for me, it does not interfere with the normal operation of sound creation. I was only concerned that it may have been an electrical fault.

I am very grateful for all replies.

Kind regards and best wishes
--- In Doepfer_a100@yahoogroups.com, analogmonster@... wrote:

>
> I agree to some extent, but he does state the frequency changes according to which modules are being used, which means it doesn't match the mains frequency
> 
> 
> 
> 
> On 7 Jul 2013, at 19:20, "anoop.sahal" <draks@...> wrote:
> 
> > 
> > 
> > I think all coil based voltage transformers will emit noise. It is often due the coils attracting and repelling one another at each voltage cycle change.
> > 
> > Winding them tightly helps initially but the coils lengthen as they age and they loosen up. Varnish helps delay the loosening by binding the coils.
> > 
> > Is the hum mains frequency matched?
> > 
> > That would indicate that the above case is likely.
> > 
> > I have only known solid state transformers not to hum.
> > 
> > i would mount the PSU boards on Rubber washers to minimise making the case a sound box.
> > 
> > Any concurrance?
> > 
> > Regards Anoop
> > --- In Doepfer_a100@yahoogroups.com, "isoldeandisobelle" <isoldeisobelle@> wrote:
> > >
> > > Hi - Thank you both for your replies.
> > > 
> > > I am not sure what you mean by ''mechanical'' but, the sound is coming from the transformer itself. It is not too loud but I can hear it from a short distance away. The earth cables are all connected properly. My other 6U case is connected to the exact same power supply and makes no noise - this is what concerned me
> > > 
> > > --- In Doepfer_a100@yahoogroups.com, Florian Anwander <fanwander@> wrote:
> > > >
> > > > Hello
> > > > 
> > > > I assume you mean a mechanical hum. Right? If so, then it should be 
> > > > related to the method how the powersupply is fixed to the housing.
> > > > 
> > > > Florian
> > > > 
> > > > 
> > > > On 07.07.13 00:31 , isoldeandisobelle wrote:
> > > > > Hi gang -
> > > > >
> > > > > I have a 6U case and a 9U case, the 9U PSU hums (which changes in frequency when different modules are in use.) - the 6U does not do this.... is this ok?
> > > > >
> > > > >
> > > > >
> > > > > ------------------------------------
> > > > >
> > > > > Yahoo! Groups Links
> > > > >
> > > > >
> > > > >
> > > > >
> > > >
> > >
> > 
> > 
> 
> 
> [Non-text portions of this message have been removed]
>

I agree to some extent, but he does state the frequency changes according to which modules are being used, which means it doesn't match the mains frequency




On 7 Jul 2013, at 19:20, "anoop.sahal" <draks@apollo111.demon.co.uk> wrote:

> 
> 
> I think all coil based voltage transformers will emit noise. It is often due the coils attracting and repelling one another at each voltage cycle change.
> 
> Winding them tightly helps initially but the coils lengthen as they age and they loosen up. Varnish helps delay the loosening by binding the coils.
> 
> Is the hum mains frequency matched?
> 
> That would indicate that the above case is likely.
> 
> I have only known solid state transformers not to hum.
> 
> i would mount the PSU boards on Rubber washers to minimise making the case a sound box.
> 
> Any concurrance?
> 
> Regards Anoop
> --- In Doepfer_a100@yahoogroups.com, "isoldeandisobelle" <isoldeisobelle@...> wrote:
> >
> > Hi - Thank you both for your replies.
> > 
> > I am not sure what you mean by ''mechanical'' but, the sound is coming from the transformer itself. It is not too loud but I can hear it from a short distance away. The earth cables are all connected properly. My other 6U case is connected to the exact same power supply and makes no noise - this is what concerned me
> > 
> > --- In Doepfer_a100@yahoogroups.com, Florian Anwander <fanwander@> wrote:
> > >
> > > Hello
> > > 
> > > I assume you mean a mechanical hum. Right? If so, then it should be 
> > > related to the method how the powersupply is fixed to the housing.
> > > 
> > > Florian
> > > 
> > > 
> > > On 07.07.13 00:31 , isoldeandisobelle wrote:
> > > > Hi gang -
> > > >
> > > > I have a 6U case and a 9U case, the 9U PSU hums (which changes in frequency when different modules are in use.) - the 6U does not do this.... is this ok?
> > > >
> > > >
> > > >
> > > > ------------------------------------
> > > >
> > > > Yahoo! Groups Links
> > > >
> > > >
> > > >
> > > >
> > >
> >
> 
> 


[Non-text portions of this message have been removed]

The led decay is normal, your 6u simply has more load so they decay faster. Glad you're not worrying any more




On 7 Jul 2013, at 20:37, "isoldeandisobelle" <isoldeisobelle@gmail.com> wrote:

> 
> Thank you very much to you both for your help.
> 
> I earlier removed a module from the 6U case and put my ear has close to the transformer has I dare, and yes, there is a slight hum being emitted, only slight and barely noticeable. I have had this case for some time and have never had a problem with it at all.
> I received this new 9U case only last week and it is empty but for a few modules - perhaps the larger size and the fact that it is empty, is just making it seem to amplify the normal operational sound of the transformer.
> I have had it on for some period and there is no abnormal operation with the modules - certainly no static, etc coming from the module face plates... the only thing beside the sound that I have noticed is, that when switched off the bus board led's take a few seconds to dim to off, whereas with the 6U they dim instantly when the case is powered off.
> 
> Reading elsewhere, I have noticed that others have experienced similar and the solution was to perhaps mount the PSU on rubber washers and the like - but, it really is not such a problem for me, it does not interfere with the normal operation of sound creation. I was only concerned that it may have been an electrical fault.
> 
> I am very grateful for all replies.
> 
> Kind regards and best wishes
> --- In Doepfer_a100@yahoogroups.com, analogmonster@... wrote:
> >
> > I agree to some extent, but he does state the frequency changes according to which modules are being used, which means it doesn't match the mains frequency
> > 
> > 
> > 
> > 
> > On 7 Jul 2013, at 19:20, "anoop.sahal" <draks@...> wrote:
> > 
> > > 
> > > 
> > > I think all coil based voltage transformers will emit noise. It is often due the coils attracting and repelling one another at each voltage cycle change.
> > > 
> > > Winding them tightly helps initially but the coils lengthen as they age and they loosen up. Varnish helps delay the loosening by binding the coils.
> > > 
> > > Is the hum mains frequency matched?
> > > 
> > > That would indicate that the above case is likely.
> > > 
> > > I have only known solid state transformers not to hum.
> > > 
> > > i would mount the PSU boards on Rubber washers to minimise making the case a sound box.
> > > 
> > > Any concurrance?
> > > 
> > > Regards Anoop
> > > --- In Doepfer_a100@yahoogroups.com, "isoldeandisobelle" <isoldeisobelle@> wrote:
> > > >
> > > > Hi - Thank you both for your replies.
> > > > 
> > > > I am not sure what you mean by ''mechanical'' but, the sound is coming from the transformer itself. It is not too loud but I can hear it from a short distance away. The earth cables are all connected properly. My other 6U case is connected to the exact same power supply and makes no noise - this is what concerned me
> > > > 
> > > > --- In Doepfer_a100@yahoogroups.com, Florian Anwander <fanwander@> wrote:
> > > > >
> > > > > Hello
> > > > > 
> > > > > I assume you mean a mechanical hum. Right? If so, then it should be 
> > > > > related to the method how the powersupply is fixed to the housing.
> > > > > 
> > > > > Florian
> > > > > 
> > > > > 
> > > > > On 07.07.13 00:31 , isoldeandisobelle wrote:
> > > > > > Hi gang -
> > > > > >
> > > > > > I have a 6U case and a 9U case, the 9U PSU hums (which changes in frequency when different modules are in use.) - the 6U does not do this.... is this ok?
> > > > > >
> > > > > >
> > > > > >
> > > > > > ------------------------------------
> > > > > >
> > > > > > Yahoo! Groups Links
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > >
> > > >
> > > 
> > > 
> > 
> > 
> > [Non-text portions of this message have been removed]
> >
> 
> 


[Non-text portions of this message have been removed]

> Hi - Thank you both for your replies.
>
> I am not sure what you mean by ''mechanical'' but, the sound is
> coming from the transformer itself. It is not too loud but I can
> hear it from a short distance away. The earth cables are all
> connected properly. My other 6U case is connected to the exact
> same power supply and makes no noise - this is what concerned me

Each transformer generates a little bit of mechanical hum. But if the hum of
the 9U case is clearly louder compared to the 6U case I'd recommend to
return the case if it's still within the return period. Replacing the power
supply (or the transformer of the supply) should solve the problem.

Best wishes
Dieter Doepfer

Hi there Dieter, thank you for the reply.

More than anything, I think that it may be outputting the same amount of hum as the 6U, but appears louder due to it's larger size and emptiness (soon to be remedied! :) )

I have learned something about transformers and power supply by asking this question - although an essential/vital component, I had never really gave it much thought beforehand.

Thank you again and best wishes.

--- In Doepfer_a100@yahoogroups.com, <yahoo@...> wrote:

>
> > Hi - Thank you both for your replies.
> >
> > I am not sure what you mean by ''mechanical'' but, the sound is
> > coming from the transformer itself. It is not too loud but I can
> > hear it from a short distance away. The earth cables are all
> > connected properly. My other 6U case is connected to the exact
> > same power supply and makes no noise - this is what concerned me
> 
> Each transformer generates a little bit of mechanical hum. But if the hum of
> the 9U case is clearly louder compared to the 6U case I'd recommend to
> return the case if it's still within the return period. Replacing the power
> supply (or the transformer of the supply) should solve the problem.
> 
> Best wishes
> Dieter Doepfer
>