Elektor Formant Modular

hi. i have a formant that i'm slowly bringing back to life. i have 2
oscillators and they are working now ( though one of them is quite
unstable) I have got a bad case of bleed to the output from all the
waveforms even though they are switched off. so if i switch off all
the waveforms and connect a headphone to the osc out, i can still hear
the waveforms ( a lot lower though) could this have anything to do
with the power supply? it doesnt have a ground plug... ( not using the
original elektor psu) or maybe something else is wrong.. any suggestions?
thanks!

--- In ElektorFormant@yahoogroups.com, "the19thbear" <the19thbear@...>
wrote:
>
> hi. i have a formant that i'm slowly bringing back to life. i have 2
> oscillators and they are working now ( though one of them is quite
> unstable) I have got a bad case of bleed to the output from all the
> waveforms even though they are switched off. so if i switch off all
> the waveforms and connect a headphone to the osc out, i can still hear
> the waveforms ( a lot lower though) could this have anything to do
> with the power supply? it doesnt have a ground plug... ( not using the
> original elektor psu) or maybe something else is wrong.. any
suggestions?
> thanks!
>

Have you replaced all the ageing electrolytics, especially the power
supply decoupling ones?

Mike

That's a good suggestion. Electrolytics deteriorate with age.
I had to replace every Tantalum condensor in my vocoder. All dead.

GB


>--- In ElektorFormant@yahoogroups.com, "the19thbear" <the19thbear@...>
>wrote:
>>
>> hi. i have a formant that i'm slowly bringing back to life. i have 2
>> oscillators and they are working now ( though one of them is quite
>> unstable) I have got a bad case of bleed to the output from all the
>> waveforms even though they are switched off. so if i switch off all
>> the waveforms and connect a headphone to the osc out, i can still hear
>> the waveforms ( a lot lower though) could this have anything to do
>> with the power supply? it doesnt have a ground plug... ( not using the
>> original elektor psu) or maybe something else is wrong.. any
>suggestions?
>> thanks!
>>
>
>Have you replaced all the ageing electrolytics, especially the power
>supply decoupling ones?
>
>Mike
>
>------------------------------------
>


-- 
______________________ _
Gerard Bik grafische vormgeving
Van Aerssenstraat 263
2582 JM  Den Haag
070 3554081

interesting tip. im in the same process (restoring an old formant system), and ive noticed some modules that were part of the system work better than others, maybe because of this. 

any other weak spots to check?  ones that dont age well?

thanks,
brendan

--- In ElektorFormant@yahoogroups.com, Gerard Bik <gbik@...> wrote:

>
> That's a good suggestion. Electrolytics deteriorate with age.
> I had to replace every Tantalum condensor in my vocoder. All dead.
> 
> GB
>

Potentiometers in general don't age well. They get noisy. And keyboard switches. :-(


>interesting tip. im in the same process (restoring an old formant system), and ive noticed some modules that were part of the system work better than others, maybe because of this.
>
>any other weak spots to check?  ones that dont age well?
>
>thanks,
>brendan
>
>--- In ElektorFormant@yahoogroups.com, Gerard Bik <gbik@...> wrote:
>>
>> That's a good suggestion. Electrolytics deteriorate with age.
>> I had to replace every Tantalum condensor in my vocoder. All dead.
>>
>> GB
>>
>
>
>
>------------------------------------
>
>Yahoo! Groups Links
>
>
>

-- 
______________________ _
Gerard Bik grafische vormgeving
Van Aerssenstraat 263
2582 JM  Den Haag
070 3554081

When I built my formant in 1977 there was output bleed, I do not believe that aging is the problem. More likely it is the basic design, the output signal is quite powerful. I tried everything to stop the bleed, screened  cables between pcb and output sockets etc etc, all to no avail. 
Eventually I solved the problem by replacing the output potentiometer with a switched pot (push to switch off). I not sure if these type of pots are still available from anywhere but that was the fix.

R_.



--- In ElektorFormant@yahoogroups.com, Gerard Bik <gbik@...> wrote:

>
> Potentiometers in general don't age well. They get noisy. And keyboard switches. :-(
> 
> 
> >interesting tip. im in the same process (restoring an old formant system), and ive noticed some modules that were part of the system work better than others, maybe because of this.
> >
> >any other weak spots to check?  ones that dont age well?
> >
> >thanks,
> >brendan
> >
> >--- In ElektorFormant@...m, Gerard Bik <gbik@> wrote:
> >>
> >> That's a good suggestion. Electrolytics deteriorate with age.
> >> I had to replace every Tantalum condensor in my vocoder. All dead.
> >>
> >> GB
> >>
> >
> >
> >
> >------------------------------------
> >
> >Yahoo! Groups Links
> >
> >
> >
> 
> -- 
> ______________________ _
> Gerard Bik grafische vormgeving
> Van Aerssenstraat 263
> 2582 JM  Den Haag
> 070 3554081
>