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Harry Bissell Lag issues

Harry Bissell Lag issues

2010-01-10 by dumpstatic

I can't find my docs for the Lag PCBs I have, but I have Harry's circuit diagram for help. I powered it up last night and it did some really strange stuff. Looking at the backside, I realized there should be some decoupling caps on the back... oops...

Question #1 - would the absence of those 4 decoupling caps cause the 10uF electrolytic caps to get quite hot?

Question #2 - I have a 4.7uF Tant cap where a mylar is suggested. Are Tant caps polarized? (one lead is longer than the other, but there are no +/- labels) Should a Tant cap work OK here?

thanks a bunch for any help,
Drew

Re: Harry Bissell Lag issues

2010-01-10 by sasami@hotkey.net.au

>Question #1 - would the absence of those 4 decoupling caps cause the 10uF

electrolytic caps to get quite hot?

No. Having the voltage across them the wrong way is what makes them hot.

>Question #2 - I have a 4.7uF Tant cap where a mylar is suggested. Are Tant

caps polarized? (one lead is longer than the other, but there are no +/-
labels) Should a Tant cap work OK here?

Tants ARE polarized. long lead is probably +VE. They may have a thick line
marked on them. I don't recall if that is pos or neg. Personally I avoid
them at all costs. They blow up too often for my liking.

Ken
_______________________________________________________________________
Ken Stone sasami@... otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

Re: Harry Bissell Lag issues

2010-01-10 by Guy

Here's the amateur of the group (the one with the now-fixed LFO)...
Tantaliums are indeed polarized. Long lead is +. I don't think you can replace a mylar with a tant.
Don't tell Ken tho, he dislikes tantaliums. ;-)

_g

Show quoted textHide quoted text

--- In cgs_synth@yahoogroups.com, "dumpstatic" <oozitron@...> wrote:
>
> I can't find my docs for the Lag PCBs I have, but I have Harry's circuit diagram for help. I powered it up last night and it did some really strange stuff. Looking at the backside, I realized there should be some decoupling caps on the back... oops...
>
> Question #1 - would the absence of those 4 decoupling caps cause the 10uF electrolytic caps to get quite hot?
>
> Question #2 - I have a 4.7uF Tant cap where a mylar is suggested. Are Tant caps polarized? (one lead is longer than the other, but there are no +/- labels) Should a Tant cap work OK here?
>
> thanks a bunch for any help,
> Drew
>

Re: Harry Bissell Lag issues

2010-01-11 by Doug

Amateurs are most welcome. ;-)

I will probably be adding one or more of Harry's LAGs to my SteamSynth project very soon.

I looked over the circuit and realized that 4.7uf (4M7???) is a VERY large mylar cap. I doubt it is easily available, if at all. This MUST be a non-polarized cap. The Tant cap is VERY polarized so do NOT use it.

Now I have no direct experience with this circuit, but I see that it is in a closed loop feedback circuit, I would suggest that the 4M7 (4.7uf) cap would most easily be replaced with two 10uf caps in series, but wired "back-to-back" - meaning the two positives are wired together and then the negative leads inserted where the plans call for the cap. Does that make sense? I hope so.

Doug

Show quoted textHide quoted text

--- In cgs_synth@yahoogroups.com, "Guy" <guy@...> wrote:
>
>
> Here's the amateur of the group (the one with the now-fixed LFO)...
> Tantaliums are indeed polarized. Long lead is +. I don't think you can replace a mylar with a tant.
> Don't tell Ken tho, he dislikes tantaliums. ;-)
>
> _g
>
>
> --- In cgs_synth@yahoogroups.com, "dumpstatic" <oozitron@> wrote:
> >
> > I can't find my docs for the Lag PCBs I have, but I have Harry's circuit diagram for help. I powered it up last night and it did some really strange stuff. Looking at the backside, I realized there should be some decoupling caps on the back... oops...
> >
> > Question #1 - would the absence of those 4 decoupling caps cause the 10uF electrolytic caps to get quite hot?
> >
> > Question #2 - I have a 4.7uF Tant cap where a mylar is suggested. Are Tant caps polarized? (one lead is longer than the other, but there are no +/- labels) Should a Tant cap work OK here?
> >
> > thanks a bunch for any help,
> > Drew
> >
>

Re: Harry Bissell Lag issues

2010-01-11 by Jason Proctor

i made a couple of Bissell Lags a while back, from CGS PCBs IIRC.
worked fine with no issues.

i can probably look up what cap i used in my Mouser order history if
anyone needs to know.

Show quoted textHide quoted text

>Amateurs are most welcome. ;-)
>
>I will probably be adding one or more of Harry's LAGs to my
>SteamSynth project very soon.
>
>I looked over the circuit and realized that 4.7uf (4M7???) is a VERY
>large mylar cap. I doubt it is easily available, if at all. This
>MUST be a non-polarized cap. The Tant cap is VERY polarized so do
>NOT use it.
>
>Now I have no direct experience with this circuit, but I see that it
>is in a closed loop feedback circuit, I would suggest that the 4M7
>(4.7uf) cap would most easily be replaced with two 10uf caps in
>series, but wired "back-to-back" - meaning the two positives are
>wired together and then the negative leads inserted where the plans
>call for the cap. Does that make sense? I hope so.
>
>Doug

Re: Harry Bissell Lag issues

2010-01-12 by Dave Kendall

Hi.

FWIW, Rapid electronics in the UK do some 4u7 non-polar caps. Not too
expensive either... ;-)

http://www.rapidonline.com

stock no; 10-5782 or stock no; 10-4110

hope this helps....

cheers,
Dave

Show quoted textHide quoted text

On Jan 11, 2010, at 23:35, Doug wrote:

> Amateurs are most welcome. ;-)
>
> I will probably be adding one or more of Harry's LAGs to my
> SteamSynth project very soon.
>
> I looked over the circuit and realized that 4.7uf (4M7???) is a VERY
> large mylar cap. I doubt it is easily available, if at all. This MUST
> be a non-polarized cap. The Tant cap is VERY polarized so do NOT use
> it.
>
> Now I have no direct experience with this circuit, but I see that it
> is in a closed loop feedback circuit, I would suggest that the 4M7
> (4.7uf) cap would most easily be replaced with two 10uf caps in
> series, but wired "back-to-back" - meaning the two positives are wired
> together and then the negative leads inserted where the plans call for
> the cap. Does that make sense? I hope so.
>
> Doug
>
> --- In cgs_synth@yahoogroups.com, "Guy" <guy@...> wrote:
> >
> >
> > Here's the amateur of the group (the one with the now-fixed LFO)...
> > Tantaliums are indeed polarized. Long lead is +. I don't think you
> can replace a mylar with a tant.
> > Don't tell Ken tho, he dislikes tantaliums. ;-)
> >
> > _g
> >
> >
> > --- In cgs_synth@yahoogroups.com, "dumpstatic" <oozitron@> wrote:
> > >
> > > I can't find my docs for the Lag PCBs I have, but I have Harry's
> circuit diagram for help. I powered it up last night and it did some
> really strange stuff. Looking at the backside, I realized there should
> be some decoupling caps on the back... oops...
> > >
> > > Question #1 - would the absence of those 4 decoupling caps cause
> the 10uF electrolytic caps to get quite hot?
> > >
> > > Question #2 - I have a 4.7uF Tant cap where a mylar is suggested.
> Are Tant caps polarized? (one lead is longer than the other, but there
> are no +/- labels) Should a Tant cap work OK here?
> > >
> > > thanks a bunch for any help,
> > > Drew
> > >
> >
>
>
>

Re: Harry Bissell Lag issues

2010-01-12 by Richard Brewster

Yes, a 4.7uf mylar is LARGE:

http://pugix.com/synth/dual-tellun-lag-processor/

That's the Tellun lag, but similar idea. You could use the Mouser part
I listed for that cap. If you can make it fit! You could also try a
4.7uf non-polar electrolytic, which is the equivalent of what Doug
suggested.

Richard Brewster

Doug wrote:

Show quoted textHide quoted text

> Amateurs are most welcome. ;-)
>
> I will probably be adding one or more of Harry's LAGs to my SteamSynth project very soon.
>
> I looked over the circuit and realized that 4.7uf (4M7???) is a VERY large mylar cap. I doubt it is easily available, if at all. This MUST be a non-polarized cap. The Tant cap is VERY polarized so do NOT use it.
>
> Now I have no direct experience with this circuit, but I see that it is in a closed loop feedback circuit, I would suggest that the 4M7 (4.7uf) cap would most easily be replaced with two 10uf caps in series, but wired "back-to-back" - meaning the two positives are wired together and then the negative leads inserted where the plans call for the cap. Does that make sense? I hope so.
>
> Doug
>
> --- In cgs_synth@yahoogroups.com, "Guy" <guy@...> wrote:
>
>> Here's the amateur of the group (the one with the now-fixed LFO)...
>> Tantaliums are indeed polarized. Long lead is +. I don't think you can replace a mylar with a tant.
>> Don't tell Ken tho, he dislikes tantaliums. ;-)
>>
>> _g
>>
>>
>> --- In cgs_synth@yahoogroups.com, "dumpstatic" <oozitron@> wrote:
>>
>>> I can't find my docs for the Lag PCBs I have, but I have Harry's circuit diagram for help. I powered it up last night and it did some really strange stuff. Looking at the backside, I realized there should be some decoupling caps on the back... oops...
>>>
>>> Question #1 - would the absence of those 4 decoupling caps cause the 10uF electrolytic caps to get quite hot?
>>>
>>> Question #2 - I have a 4.7uF Tant cap where a mylar is suggested. Are Tant caps polarized? (one lead is longer than the other, but there are no +/- labels) Should a Tant cap work OK here?
>>>
>>> thanks a bunch for any help,
>>> Drew
>>>
>>>
>
>