[Boatanchors] NEED TUBE INFO

Sat Jul 21 20:51:54 EDT 2007

Hello to the list..............

Seems there is no argument that a type 280 rectifier is the same as a 
type 80.  But the question remains, is there a tube with a type number 
of 280A that has a 2.5v filament.

The answer is YES!  The 280A is a mercury vapor rectifier that has a 
2.5v filament.

Granted, it is an antique.................but it exists, and there is 
reference to it's existence.  The telephone company (Bell System) used 
them for years.  Complete with their 2.5v filaments.

A fellow named Ludwell Sibley wrote a pretty good book a few years back 
as a reference for tube collectors.  Luddy did extensive research into 
the origin and history of tubes and their designs and put it all into 
his reference manual.  For those who are AWA members, you probably know 
of whom I speak.

For the Non-Believers................ Obtain his reference manual.  
Look on page 158 under the designator 253A.  Read the specs.  Then, 
skip over to page 159.  Read the heading under designator 
280A...................

For years, we've successfully interchanged type 80's with type 280's 
and they worked.  As well they should.  The much later 5Y3 is a variant 
of the type 80.  Basing is different, but in many cases can be used 
depending on circuit configuration.  But if you encounter a 280A, 
better check first before using more than 2.5v on the filaments.  Or 
you might have a collectible dud.

Best 73 to all...............

YMMV

W4MIL
Chuck

-----Original Message-----
From: EP Swynar <gswynar at durham.net>
To: Brian Goldsmith <brian.goldsmith at echo1.com.au>; 'BOATANCHORS' 
<boatanchors at mailman.qth.net>
Sent: Sat, 21 Jul 2007 7:20 pm
Subject: Re: [Boatanchors] NEED TUBE INFO

Hi Guys,

I don't know where the notion came up that just because a rig uses 2.5
filament tubes then, by default, the rectifier tube has to be 2.5 volts 
as
well...!

Nothing is further from the truth...and I hate to tell the non-believers
reading this, but an 80 is just like a 280, performance & specs-wise 
--- the
sole difference *could* be in the glass envelope used by each, i.e. the
older 280-type uses a globe / balloon envelope, whereas the 80 (or, in 
the
shortened form it became known as, the '80) has a shoulder-type 
envelope...

Check any of the older issues of QST: you'll see power supplies 
illustrated
therein using the abbreviated '80 designator (short for 280), hooked-up 
to a
5.0 VAC filament winding of the power transformer.

I've interchanged 280 tubes with 80 tubes in my HB projects here, and 
have
NEVER "flamed-out" the filament of ANY supposed 2.5 volt 280 by 
treating it
like an 80, with 5 vac on the filament...that SHOULD have happened if 
there
was a difference between the two types, and in very short order, too. 
But it
never has, never will...

Perhaps somebody here has 80 / 280 tubes confused with the mercury 
vapoured
'83 tube...? Now, it --- or some other designation --- share the same
characteristics, EXCEPT for the filament voltages, i.e. 2.5 vac versus 
5.0
vac...

~73!~ Eddy VE3CUI - VE3XZ

***********************

----- Original Message -----
From: "Brian Goldsmith" <brian.goldsmith at echo1.com.au>
To: "'BOATANCHORS'" <boatanchors at mailman.qth.net>
Sent: Saturday, July 21, 2007 5:12 AM
Subject: [Boatanchors] NEED TUBE INFO

>
>
> -----Original Message-----
> From: David Hollander
>
>
> Brian - once again, the 280 rectifier is a 2.5 volt filament tube. It 
is
> the2.5 volt version of the 80 rectifier. The National 5887 doghouse 
supply
> uses one to power the FB-7 receiver 2.5 volt tube version. The 
National
5880
> doghouse which is for the 2.5 volt version of the SW-3 also has a 280 
in
the
> power supply. The doghouse supplies for the early national receivers 
using
6
> volt tubes uses an 80 rectifier.
>
>
> ***** The following people from the Tube Collectors Association do not
agree
> with you and present some data sheets to back them up.I agree with you
about
> the 280A.
>
> >>1) Re: 280 Rectifier
>     Posted by: "Donald Daykin" daykin at ameritech.net drdaykin
>     Date: Fri Jul 20, 2007 6:54 am ((PDT))
>
> Believe me, the 280 has a 5-volt filament. Since they need separate
> windings, it makes no difference what the voltage is for the other 
tubes.
>
> Donald
>
> >>2) 2c. Re: 280 Rectifier
>     Posted by: "Roger P. Walker" rp.walker at btconnect.com rp.walker
>     Date: Fri Jul 20, 2007 7:23 am ((PDT))
>
> The 280A is a MV rectifier with a heater of 2.5V 3A but 280 seems to 
be 5V
>
>
> >>3) From: tubecollectorsassociation at yahoogroups.com
> [mailto:tubecollectorsassociation at yahoogroups.com] On Behalf Of Donald
> Daykin
> Sent: 20 July 2007 14:54
> To: tubecollectorsassociation at yahoogroups.com
> Subject: Re: [TCA] 280 Rectifier
>
> Believe me, the 280 has a 5-volt filament. Since they need separate
> windings, it makes no difference what the voltage is for the other 
tubes.
>
> >>4) 2d. Re: 280 Rectifier
>     Posted by: "Tony" tonydaggs at comcast.net bone433
>     Date: Fri Jul 20, 2007 5:36 pm ((PDT))
>
>
> http://www.nj7p.org/Tube4.php?tube=280
>
> Tony
>
>
>
> Brian Goldsmith.
>
>
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