Steiner Filter VCF Current draw question.
2014-09-04 by hollispete
Hi Ken
I am looking at supply options for the Steiner VCF. Do you know the current draw of a working PCB? Any recommendations on dual supply design, please?
Thanks,
Pete
Thread
Steiner Filter VCF Current draw question.
Re: Steiner Filter VCF Current draw question.
2014-09-04 by cg_synth
it's about 15ma per rail. If that is the only module you have, you could run it on something like
the CGS14 (no PCB available)
Short Circuits Three Project - Regulated +/- 12V Power Supply
the CGS14 (no PCB available)
or something like this:
Short Circuits Three Project - Regulated +/- 12V Power Supply
Re: Steiner Filter VCF Current draw question.
2014-09-04 by Andre Majorel
On 2014-09-04 06:45 -0700, otherunicorn@... [cgs_synth] wrote:
Show quoted textHide quoted text
> it's about 15ma per rail. If that is the only module you have,Ken, there may be an error in the schematic. The cap between the
> you could run it on something like the CGS14
> http://www.cgs.synth.net/modules/cgs14_psu.html
output of the 7915 and ground should be 1 µF, not 100 nF. (100 nF
between output of 7-EIGHT-15 and ground is correct.)
In the parts list,
100n 4
should be replaced by
100n 3
1µF 1
> (no PCB available)If you make more, the hole spacing for that cap might benefit
from being reduced to 2.5 mm down from 5 mm.
--
André Majorel http://www.teaser.fr/~amajorel/
Re: Steiner Filter VCF Current draw question.
2014-09-04 by Ken Stone
No, 100n is correct. What makes you think it should be 1uF?
Show quoted textHide quoted text
On Fri, Sep 5, 2014 at 12:23 AM, Andre Majorel aym-htnys@... [cgs_synth] <cgs_synth@yahoogroups.com> wrote:
On 2014-09-04 06:45 -0700, otherunicorn@... [cgs_synth] wrote:> http://www.cgs.synth.net/modules/cgs14_psu.html
> it's about 15ma per rail. If that is the only module you have,
> you could run it on something like the CGS14
Ken, there may be an error in the schematic. The cap between the
output of the 7915 and ground should be 1 µF, not 100 nF. (100 nF
between output of 7-EIGHT-15 and ground is correct.)
In the parts list,
100n 4
should be replaced by
100n 3
1µF 1
> (no PCB available)
If you make more, the hole spacing for that cap might benefit
from being reduced to 2.5 mm down from 5 mm.
--
André Majorel http://www.teaser.fr/~amajorel/
--
Re: Steiner Filter VCF Current draw question.
2014-09-05 by Tom Farrand
Ken,
I believe André is correct. The 1uF is suggested for the output in
the datasheet, as is a 2.2 uF tantalum on the input side (22uF if
aluminum electrolytic). I have found 7915s to be a bit fussy and
years ago I didn't noticed that suggested arrangement to my chagrin
and wanky operation resulted. So I bodged in the correct caps and
everything worked as intended. Perhaps not all 7915s require this and
could be manufacturer dependent. STM parts do require this according
to the data sheet. It is too long ago to recall the specific errant
behavior but the - supply was "bonkers" without them.
Different sets of circumstance related to layout and wiring will
probably have a lot to do with seeing strange behavior or not. With
the suggested caps in place, the power supply is pretty much
rock-solid. The 7815 parts are happy with the 100n caps and are good
to go. I have not looked into why the difference between 7815 and
7915 but the issue is real (but possibly not for all manufacturers of
7915 parts).
Peace.
Tom Farrand
(Good catch André!)
I believe André is correct. The 1uF is suggested for the output in
the datasheet, as is a 2.2 uF tantalum on the input side (22uF if
aluminum electrolytic). I have found 7915s to be a bit fussy and
years ago I didn't noticed that suggested arrangement to my chagrin
and wanky operation resulted. So I bodged in the correct caps and
everything worked as intended. Perhaps not all 7915s require this and
could be manufacturer dependent. STM parts do require this according
to the data sheet. It is too long ago to recall the specific errant
behavior but the - supply was "bonkers" without them.
Different sets of circumstance related to layout and wiring will
probably have a lot to do with seeing strange behavior or not. With
the suggested caps in place, the power supply is pretty much
rock-solid. The 7815 parts are happy with the 100n caps and are good
to go. I have not looked into why the difference between 7815 and
7915 but the issue is real (but possibly not for all manufacturers of
7915 parts).
Peace.
Tom Farrand
(Good catch André!)
Show quoted textHide quoted text
On Thu, Sep 4, 2014 at 5:37 PM, Ken Stone otherunicorn@...
[cgs_synth] <cgs_synth@yahoogroups.com> wrote:
>
>
> No, 100n is correct. What makes you think it should be 1uF?
>
>
> On Fri, Sep 5, 2014 at 12:23 AM, Andre Majorel aym-htnys@...
> [cgs_synth] <cgs_synth@yahoogroups.com> wrote:
>>
>>
>>
>> On 2014-09-04 06:45 -0700, otherunicorn@... [cgs_synth] wrote:
>>
>> > it's about 15ma per rail. If that is the only module you have,
>> > you could run it on something like the CGS14
>> > http://www.cgs.synth.net/modules/cgs14_psu.html
>>
>> Ken, there may be an error in the schematic. The cap between the
>> output of the 7915 and ground should be 1 µF, not 100 nF. (100 nF
>> between output of 7-EIGHT-15 and ground is correct.)
>>
>> In the parts list,
>>
>> 100n 4
>>
>> should be replaced by
>>
>> 100n 3
>> 1µF 1
>>
>> > (no PCB available)
>>
>> If you make more, the hole spacing for that cap might benefit
>> from being reduced to 2.5 mm down from 5 mm.
>>
>> --
>> André Majorel http://www.teaser.fr/~amajorel/
>
>
>
>
> --
> Ken Stone otherunicorn@...
> Modular Synth PCBs for sale <http://www.cgs.synth.net/>
>
>
Re: Steiner Filter VCF Current draw question.
2014-09-05 by Ken Stone
It seems to be manufacturer related. 7800 don't require ANY cap on the output according the the Motorola databook. I was taught the low impedance of the 100n was more effective than any electrolytic in that position. Of course, that doesn't mean it was right.
I always found having a minimum load to be more important. If there is no load attached, some regulators simply go nuts. That's the purpose of the resistor and LED on the output.
I always found having a minimum load to be more important. If there is no load attached, some regulators simply go nuts. That's the purpose of the resistor and LED on the output.
Show quoted textHide quoted text
On Fri, Sep 5, 2014 at 12:32 PM, Tom Farrand mbedtom@... [cgs_synth] <cgs_synth@yahoogroups.com> wrote:Ken,
I believe André is correct. The 1uF is suggested for the output in
the datasheet, as is a 2.2 uF tantalum on the input side (22uF if
aluminum electrolytic). I have found 7915s to be a bit fussy and
years ago I didn't noticed that suggested arrangement to my chagrin
and wanky operation resulted. So I bodged in the correct caps and
everything worked as intended. Perhaps not all 7915s require this and
could be manufacturer dependent. STM parts do require this according
to the data sheet. It is too long ago to recall the specific errant
behavior but the - supply was "bonkers" without them.
Different sets of circumstance related to layout and wiring will
probably have a lot to do with seeing strange behavior or not. With
the suggested caps in place, the power supply is pretty much
rock-solid. The 7815 parts are happy with the 100n caps and are good
to go. I have not looked into why the difference between 7815 and
7915 but the issue is real (but possibly not for all manufacturers of
7915 parts).
Peace.
Tom Farrand
(Good catch André!)
On Thu, Sep 4, 2014 at 5:37 PM, Ken Stone otherunicorn@...
[cgs_synth] <cgs_synth@yahoogroups.com> wrote:
>
>
> No, 100n is correct. What makes you think it should be 1uF?
>
>
> On Fri, Sep 5, 2014 at 12:23 AM, Andre Majorel aym-htnys@...
> [cgs_synth] <cgs_synth@yahoogroups.com> wrote:
>>
>>
>>
>> On 2014-09-04 06:45 -0700, otherunicorn@... [cgs_synth] wrote:
>>
>> > it's about 15ma per rail. If that is the only module you have,
>> > you could run it on something like the CGS14
>> > http://www.cgs.synth.net/modules/cgs14_psu.html
>>
>> Ken, there may be an error in the schematic. The cap between the
>> output of the 7915 and ground should be 1 µF, not 100 nF. (100 nF
>> between output of 7-EIGHT-15 and ground is correct.)
>>
>> In the parts list,
>>
>> 100n 4
>>
>> should be replaced by
>>
>> 100n 3
>> 1µF 1
>>
>> > (no PCB available)
>>
>> If you make more, the hole spacing for that cap might benefit
>> from being reduced to 2.5 mm down from 5 mm.
>>
>> --
>> André Majorel http://www.teaser.fr/~amajorel/
>
>
>
>
> --
> Ken Stone otherunicorn@...
> Modular Synth PCBs for sale <http://www.cgs.synth.net/>
>
>
--