[sdiy] MG-1 first mods, VC res

[James Patchell]

Yes you can, but, depending on the circumstances, I try to avoid doing 
this.  If you need both a 24 and a 15 volt supply, sure, why not.  As long 
as the current through both regulators is within what they can handle, no 
problem...but remember, just because the spec sheet says 1.5 amps or 
whatever...what you really need to check is the max power...if you are 
going to regulate 24 volts down to 15, and also run 1 amp through it, that 
is 9 watts you need to get rid of...you will need a pretty sizeable heat 
sink to do that.

At 12:58 PM 10/31/2004 -0500, jamhoney wrote:
> > ... 35V is the MAXIMUM
> > for all 78xx and 79xx regulators, except the 7824 and 7924.
>
>Can you cascade 2 regulators? Like, transformer --> 7824 --> 7815? I
>believe it's okay, but...
>
>Is there limit on the maximum load? Example: Given a 7824 and a 7815
>that are each rated at 1 Amp, can you squeeze a full Amp though the
>7815? I'll guess that you have to allow for some current loss at the
>second regulator.
>--
>john
>
>
>----- Original Message -----
>From: "harrybissell" <harrybissell at prodigy.net>
>To: "Metrophage" <c0r3dump23 at yahoo.com>
>Cc: <synth-diy at dropmix.xs4all.nl>
>Sent: Sunday, October 31, 2004 2:35 PM
>Subject: Re: [sdiy] MG-1 first mods, VC res
>
>
> > Metrophage wrote: <snipp'd>
> >
> > > These things get extremely hot! Might this be because the 58vct
> > > transformer is a but much for +12/-15 volts? I wonder if the
>regulators
> > > might be happier with something like 35vct. Opinions?
> >
> > If that is 58vct AC, the DC voltage would be just over 40V.   35V is
>the
> > MAXIMUM
> > for all 78xx and 79xx regulators, except the 7824 and 7924.  You are
> > dancing with
> > sudden death here.
> >
> > Yes, that transformer is TOO high a voltage. I'd agree with the
>35VCT
> > (actually 36vct, dual
> > 18V secondaries).  Even a 48VCT is too high for 15V supplies.
> >
> > H^) harry
> >
> > >
> > >
> > > CJ

         -Jim
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