Non-polarised electrolytic capacitors needed!
 

HI All

I need a quantity of non-polarised Electrolytic caps, radial-ended, in
order to re-cap an old Lowrey electronic organ.

According to the parts list the original components are 3uF / 20V -
but something near to this (maybe 4.7u) would do - likewise the
voltage rating - but component size is fairly important as the
replacements need to fit in place of the originals (5mm diameter /
11mm long).

There's one of these components for every key on the upper manual -
they control key sustain - so about 40 would do nicely.

I can find a 3.3uf / 100V at 34p per 5 (www.cpc.co.uk) - wonder if
anybody knows of any alternative UK suppliers, tried Maplin & RS
without success..... any other suggestions please ?

TIA
Adrian
Suffolk UK

"Adrian Brentnall" wrote in message
...
HI All

I need a quantity of non-polarised Electrolytic caps, radial-ended, in
order to re-cap an old Lowrey electronic organ.

According to the parts list the original components are 3uF / 20V -
but something near to this (maybe 4.7u) would do - likewise the
voltage rating - but component size is fairly important as the
replacements need to fit in place of the originals (5mm diameter /
11mm long).

There's one of these components for every key on the upper manual -
they control key sustain - so about 40 would do nicely.

I can find a 3.3uf / 100V at 34p per 5 (www.cpc.co.uk) - wonder if
anybody knows of any alternative UK suppliers, tried Maplin & RS
without success..... any other suggestions please ?

TIA
Adrian
Suffolk UK

Rapid Electronics do a range of non-polarised here
http://www.rapidelectronics.co.uk/rk...2536&XPAGENO=1

(from http://www.rapidelectronics.co.uk/) - they do a 4u7 35v in a case size
of 11 x 5mm for £0.048, or cheaper in quantity.
They also do a 3u3 100V in a case that's 11 x 6mm for 7p each (or 6.4p if
you want 40) - but I'm not sure how well a 100V rated non-polarised would
behave with less than 20V on it.

Since no doubt you're doing this for sound quality reasons, might I suggest you
consider better caps, like the poly dipped kind, or maybe those designed for
high end speaker crossovers.

Not only should they last longer, but they'll likely have lower ESR and the
capacitance will be more accurate. If this thing is older, lytics weren't quite
as small back then and you might just be able to fit them in the space you
have. Another reason for doing this is that electrolytics caps of the newer
type seem to be a pariah to the equipment in which they're installed.

Having designed and built a few amps, I avoid using electrolytics in the audio
path like the plague. Only if and when nessecary. Of course I'm going to use
them for power supply filters, but in the audio path I think they're bad news.

Even if you wind up using 'lytics, try to find some good ones, i.e. not the
kind they use in TVs. Possibly you could talk to someone at a local high-end
audio repair facility. They would know more about where to get such parts in
your area.

JURB

HI Harvey

Rapid Electronics do a range of non-polarised here
http://www.rapidelectronics.co.uk/rk...2536&XPAGENO=1

(from http://www.rapidelectronics.co.uk/) - they do a 4u7 35v in a case size
of 11 x 5mm for £0.048, or cheaper in quantity.
They also do a 3u3 100V in a case that's 11 x 6mm for 7p each (or 6.4p if
you want 40) - but I'm not sure how well a 100V rated non-polarised would
behave with less than 20V on it.


Many thanks - looks like Rapid are the ones - reasonably priced as
well - wonderful !

I'm not sure what the likely effect are of running an electrolytic at
1/5 of rated voltage.......... so probably best to go for the 35V
ones.

These caps are in a pretty undemanding circuit - they provide a
sustain effect by charging & discharging through a couple of diodes -
so as long as they're all the same (nominal!) value - then the exact
value isn't critical......

I've had three or four of them fail so far - so it seems like a good
time to change the lot of them - perhaps the organ will run for
another 30 years after that !

Many thanks
Adrian
Suffolk UK

HI Jurb
Thanks for the comments

On 05 Dec 2004 22:36:27 GMT, (JURB6006) wrote:

Since no doubt you're doing this for sound quality reasons, might I suggest you
consider better caps, like the poly dipped kind, or maybe those designed for
high end speaker crossovers.

I'm not really convinced in this particular case - I're rather
restore to original spec. instead of 'improving' things - I should
really be spending the time practicing my organ playing rather than
tinkering anyway !


Not only should they last longer, but they'll likely have lower ESR and the
capacitance will be more accurate. If this thing is older, lytics weren't quite
as small back then and you might just be able to fit them in the space you
have. Another reason for doing this is that electrolytics caps of the newer
type seem to be a pariah to the equipment in which they're installed.

These caps provide a simple 'sustain' effect by effectively keeping
the line associated with a particular key / note "pressed" once it has
been physically released. No doubt it would be ideal if they were all
exactly the same value - but I'm not about to sort through a bin of
C's in order to find 40 matched components!


Having designed and built a few amps, I avoid using electrolytics in the audio
path like the plague. Only if and when nessecary. Of course I'm going to use
them for power supply filters, but in the audio path I think they're bad news.

Even if you wind up using 'lytics, try to find some good ones, i.e. not the
kind they use in TVs. Possibly you could talk to someone at a local high-end
audio repair facility. They would know more about where to get such parts in
your area.

I've found a local supplier - I guess I can always re-cap an octave of
the keyboard and satisfy myself that it's working OK before commiting
to all 40 notes g

Many thanks for your comments
Adrian
Suffolk UK