[sdiy] 914 & 4148 diodes..

[Roy J. Tellason]

On Wednesday 21 May 2008 14:20, Tom Corbitt wrote:
> I suspect that as the industry got better at the foundry process, they
> improved things to the point where they no longer had to use a
> different process for the two diodes, so they now sell you the same
> diode no matter if you ask for the 914 or the 4148 (much like what
> happens when you go in an autoparts store and ask for a replacement
> alternator. They'll sell you one that mets or exceeds the specs of the
> old one, but you'll notice the extra mounting holes that allow it to
> work on other cars as well) Years ago I dug thru some old data books
> and think I remember seeing that the diodes had slightly different
> voltage ratings (like 5V)

There were diffrerences in spec,  but I believe that the process improvements 
you mention are a lot of it these days.  Like the 1N400x series rectifiers,  
it makes no sense to me to buy anything but the 1000V part,  and I've read 
somewhere that parts marked otherwise that are new actually cost more for the 
vairant marking but that they're all the same parts.

> You see this in tubes, where somebody was making a televsion set and
> needed a slightly different spec, so a tube gets a different number
> but in reality the repair guy just throws in the cheaper more common
> one when he comes to replace it. Over time the numbers become
> interchangable.

I think with tubes it went the other way,  where they were actually starting 
out as different tubes by different makers,  but that as makers merged and 
more than one type number started appearing on tubes that were similar 
enough,  the small differences were ironed out.  And there were often similar 
enough characteristics to be able to substitute one number for another,  I 
have a "tube substitution book" around here someplace from back in those 
days...

> Tom C.
>
> On Wed, May 21, 2008 at 12:35 PM, James Elliott <johans121 at yahoo.com> wrote:
> > Cool!
> > Thanks for the feedback everybody!
> > -Jim
> >
> >
> > ----- Original Message ----
> > From: Tom Wiltshire <tom at electricdruid.net>
> > To: Paul Perry <pfperry at melbpc.org.au>
> > Cc: Synth-diy at dropmix.xs4all.nl
> > Sent: Wednesday, May 21, 2008 4:07:02 AM
> > Subject: Re: [sdiy] 914 & 4148 diodes...
> >
> > On 21 May 2008, at 06:49, Paul Perry wrote:
> >> If there's a difference, I've never noticed it!
> >>
> >> paul perry Melbourne Australia
> >
> > Me neither. I've even used them for fuzz circuits where you hear the
> > characteristics directly and I can't hear any difference. Other types
> > of diode (rectifiers, germaniums, LEDs, etc) usually give you a
> > variation in the sound.
> >
> > T.
> >
> >
> >
> >
> >
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> >
> >
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