what is a dual tracking regulator for?

T

tempus fugit

Guest
Hey all;

I'm trying to get a (music) keyboard up and running, and I think the PS is
kaput. One of the components is MC1468, a dual tracking regulator. The unit
uses +/-15v, at about 200mA. I would just replace the 1468, but I can't find
one. It does specify in the service manual that the -15v has to be
exactly -15v for the keyboard to function properly, and that since the -15
tracks the +15, that the +15 should be pretty accurate (no noise) too.

If I can't find a replacement 1468, couldn't I just replace the current
supply with 78 and 7915? I've used these before, and they are pretty
accurate. If accuracy is an issue, maybe 317 and 337 trimmed to exactly the
right values? I'm not sure why the PS is so elaborate here (maybe because
it's older -mid 70s?), but it seems to me that a simple pair of voltage
regulators would do the trick.
 
tempus fugit wrote:
Hey all;

I'm trying to get a (music) keyboard up and running, and I think the PS is
kaput. One of the components is MC1468, a dual tracking regulator. The unit
uses +/-15v, at about 200mA. I would just replace the 1468, but I can't find
one. It does specify in the service manual that the -15v has to be
exactly -15v for the keyboard to function properly, and that since the -15
tracks the +15, that the +15 should be pretty accurate (no noise) too.

If I can't find a replacement 1468, couldn't I just replace the current
supply with 78 and 7915? I've used these before, and they are pretty
accurate. If accuracy is an issue, maybe 317 and 337 trimmed to exactly the
right values? I'm not sure why the PS is so elaborate here (maybe because
it's older -mid 70s?), but it seems to me that a simple pair of voltage
regulators would do the trick.
Click to expand...
I think i have a couple good used ones.
--
I say, the boy is so stupid that he tried to make a back up copy of his
hard drive on the Xerox machine!

Michael A. Terrell
Central Florida
 
"tempus fugit" <toccata.no.spam@ciaccess.com> wrote in message
news:xwoyb.21665$Pl1.3870@nntp-post.primus.ca...
Hey all;

I'm trying to get a (music) keyboard up and running, and I think the PS is
kaput. One of the components is MC1468, a dual tracking regulator. The
unit
uses +/-15v, at about 200mA. I would just replace the 1468, but I can't
find
one. It does specify in the service manual that the -15v has to be
exactly -15v for the keyboard to function properly, and that since the -15
tracks the +15, that the +15 should be pretty accurate (no noise) too.

If I can't find a replacement 1468, couldn't I just replace the current
supply with 78 and 7915? I've used these before, and they are pretty
accurate. If accuracy is an issue, maybe 317 and 337 trimmed to exactly
the
right values? I'm not sure why the PS is so elaborate here (maybe because
it's older -mid 70s?), but it seems to me that a simple pair of voltage
regulators would do the trick.
Click to expand...
Tempus -

The reason for a dual tracking regulator is that if the voltage of one
regulator goes up (or down) with temperature (or load or input voltage), the
other regulator goes up or down by the same amount, leaving the difference
between the two voltages at exactly zero. Trimming non tracking regulators
to the exact same (but opposite) voltage will not necessarily preserve the
zero difference between them under varying conditions, should the circuit(s)
being driven require this.

The NTE - 1468 http://www.actionelectronic.com/cgi-bin/vcat/CatalogMgr.pl
seems to be an exact replacement.
 
Thanks Baph.

That makes things a little more of a challenge then. So a regulator doesn't
keep a steady voltage if temperature changes are thrown into the mix?

The NTE 1468 is a SIP audio output amp, but if you have any other
suggestions for a drop in replacement, let me know. Oh, and more good news -
it's ceramic encapsulated rather than plastic.


"Baphomet" <no.spam@no.spam.us> wrote in message
news:vskbuuf6th1k16@corp.supernews.com...
"tempus fugit" <toccata.no.spam@ciaccess.com> wrote in message
news:xwoyb.21665$Pl1.3870@nntp-post.primus.ca...
Hey all;

I'm trying to get a (music) keyboard up and running, and I think the PS
is
kaput. One of the components is MC1468, a dual tracking regulator. The
unit
uses +/-15v, at about 200mA. I would just replace the 1468, but I can't
find
one. It does specify in the service manual that the -15v has to be
exactly -15v for the keyboard to function properly, and that since
the -15
tracks the +15, that the +15 should be pretty accurate (no noise) too.

If I can't find a replacement 1468, couldn't I just replace the current
supply with 78 and 7915? I've used these before, and they are pretty
accurate. If accuracy is an issue, maybe 317 and 337 trimmed to exactly
the
right values? I'm not sure why the PS is so elaborate here (maybe
because
it's older -mid 70s?), but it seems to me that a simple pair of voltage
regulators would do the trick.

Tempus -

The reason for a dual tracking regulator is that if the voltage of one
regulator goes up (or down) with temperature (or load or input voltage),
the
other regulator goes up or down by the same amount, leaving the difference
between the two voltages at exactly zero. Trimming non tracking regulators
to the exact same (but opposite) voltage will not necessarily preserve the
zero difference between them under varying conditions, should the
circuit(s)
being driven require this.

The NTE - 1468 http://www.actionelectronic.com/cgi-bin/vcat/CatalogMgr.pl
seems to be an exact replacement.
Click to expand...
 
"tempus fugit" <toccata.no.spam@ciaccess.com> wrote in message
news:NMwyb.22547$mm5.22122@nntp-post.primus.ca...
Thanks Baph.

That makes things a little more of a challenge then. So a regulator
doesn't
keep a steady voltage if temperature changes are thrown into the mix?
Click to expand...
Well, it may or may not, depending upon the particular regulator. I think
the point that I was trying, however ineptly, to make is that since I don't
know how critical your circuit is (and for the purposes of argument, I am
assuming it is because it called for a dual tracking regulator) to a voltage
differential between regulators, temperature variations may play a
significant factor.

The NTE 1468 is a SIP audio output amp, but if you have any other
suggestions for a drop in replacement, let me know. Oh, and more good
news -
it's ceramic encapsulated rather than plastic.
Click to expand...
I don't know where the hell I got that number from. Sorry for the goof up. I
think Michael A. Terrell said that he thought he might have several good
ones lying around.

snip...snip...snip...
 
"Baphomet" <no.spam@no.spam.us> wrote in message
news:vsm90onhk3jq21@corp.supernews.com...
"tempus fugit" <toccata.no.spam@ciaccess.com> wrote in message
news:NMwyb.22547$mm5.22122@nntp-post.primus.ca...
Thanks Baph.

That makes things a little more of a challenge then. So a regulator
doesn't
keep a steady voltage if temperature changes are thrown into the mix?

Well, it may or may not, depending upon the particular regulator. I think
the point that I was trying, however ineptly, to make is that since I
don't
know how critical your circuit is (and for the purposes of argument, I am
assuming it is because it called for a dual tracking regulator) to a
voltage
differential between regulators, temperature variations may play a
significant factor.

The NTE 1468 is a SIP audio output amp, but if you have any other
suggestions for a drop in replacement, let me know. Oh, and more good
news -
it's ceramic encapsulated rather than plastic.

I don't know where the hell I got that number from. Sorry for the goof up.
I
think Michael A. Terrell said that he thought he might have several good
ones lying around.
Click to expand...
Tempus - try this source http://members.aol.com/DBmElect/moogpt.html

snip...snip...snip...
 
"tempus fugit" <toccata.no.spam@ciaccess.com> wrote in message
news:iPHyb.23715$XH1.16256@nntp-post.primus.ca...
Tempus - try this source http://members.aol.com/DBmElect/moogpt.html

lol - guess what I need it for?
Click to expand...
No clue :) It would be interesting to see a schematic in order to see why
the designer thought it necessary to use a dual tracking regulator in the
first place.
 
A moog keyboard. Want me to post the schem at the bin group (otherwise I
could post a link to a download)?

"Baphomet" <no.spam@no.spam.us> wrote in message
news:vsml9vb6fmqhe6@corp.supernews.com...
"tempus fugit" <toccata.no.spam@ciaccess.com> wrote in message
news:iPHyb.23715$XH1.16256@nntp-post.primus.ca...
Tempus - try this source http://members.aol.com/DBmElect/moogpt.html

lol - guess what I need it for?

No clue :) It would be interesting to see a schematic in order to see
why
the designer thought it necessary to use a dual tracking regulator in the
first place.
Click to expand...
 
Are they the ceramic version (MC1468CP-1)?

If so I might be interested in one.

Thanks


"Michael A. Terrell" <mike.terrell@earthlink.net> wrote in message
news:3FCA2681.4BD6B101@earthlink.net...
tempus fugit wrote:

Hey all;

I'm trying to get a (music) keyboard up and running, and I think the PS
is
kaput. One of the components is MC1468, a dual tracking regulator. The
unit
uses +/-15v, at about 200mA. I would just replace the 1468, but I can't
find
one. It does specify in the service manual that the -15v has to be
exactly -15v for the keyboard to function properly, and that since
the -15
tracks the +15, that the +15 should be pretty accurate (no noise) too.

If I can't find a replacement 1468, couldn't I just replace the current
supply with 78 and 7915? I've used these before, and they are pretty
accurate. If accuracy is an issue, maybe 317 and 337 trimmed to exactly
the
right values? I'm not sure why the PS is so elaborate here (maybe
because
it's older -mid 70s?), but it seems to me that a simple pair of voltage
regulators would do the trick.

I think i have a couple good used ones.
--
I say, the boy is so stupid that he tried to make a back up copy of his
hard drive on the Xerox machine!

Michael A. Terrell
Central Florida
Click to expand...
 
"tempus fugit" <toccata.no.spam@ciaccess.com> wrote in message
news:9qMyb.24203$Z44.20375@nntp-post.primus.ca...
A moog keyboard. Want me to post the schem at the bin group (otherwise I
could post a link to a download)?
Click to expand...

Absolutely...please post to alt.binaries.schematics.electronic. Let's see
what's so critical that they need a dual tracking supply and ceramic, no
less.


snip...snip...snip...
 
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