[sdiy] spring reverb & hum

[mark verbos]

Is that not what the Paia verison does? i tihnk it makes an inverted 
verison of the signal and sends both through indipendant springs, then 
subracts the outputs to cancel the hum and keep the signal. Something 
like a balanced line or a humbucker.

mark

Richard Wentk wrote:

> At 23:54 13/11/2002 +0100, you wrote:
>
>> Hello
>>
>> My Doepfer A-100 Modular's spring reverb picks up a terrible amount 
>> of hum
>> from the transformer. Doepfer's only suggestion was to move the unit 
>> further
>> away from the rack with the transformer in it.
>>
>> Any suggestions on how to make a spring reverb less hum-sensitive?
>
>
> Following on from the humbucker idea - how about running the signal 
> though a bare wire next to the reverb, or even through the reverb tank 
> and using that as a hum pick up? Then subtracting that signal from the 
> reverb output? You'll probably need to trim it to get it right and 
> perhaps add some filtering. But with a bit of tweaking you should be 
> able to get near perfect cancellation.
>
> Alternatively use two reverb units and subtract one from the other. Of 
> course you'll get some weird subtractive version of the different 
> spring responses - which probably won't be what you want, but will 
> sound interesting all the same. :)
>
> To be honest I think the 'Just move it' reply is not very 
> professional. There's no reason why a spring reverb needs to hum badly 
> if it's designed properly. I'd also be worried that if I were getting 
> that much hum from one module, the transformer is radiating more 
> strongly than it should do, with there's a danger of getting hum 
> within other modules too.
>
> Richard
>
>
>