[Boatanchors] Re: [Heathkit] Question on 12AU7

[jeremy-ca]

Just about all you ever need to know about those tubes and many others is on 
the site I posted on here yesterday.
If you notice; not all manufacturers report identical specifications.

http://www.tubedata.org/

Carl
KM1H

----- Original Message ----- 
From: "Revcom" <revcom at wbsnet.org>
To: "Dan Pividal" <dpividal at tampabay.rr.com>; "boatanchors" 
<boatanchors at mailman.qth.net>; <heathkit at mailman.qth.net>
Sent: Saturday, February 02, 2008 11:57 AM
Subject: Re: [Heathkit] Question on 12AU7


> Dan,
> I am by no means an expert on this, nor an engineer, so others may
> add to the comments that know a lot more.
>
> When was doing a lot of tube type service work, we had both 12AU7s
> and 5814s.  Boss said to use the 5814 for long life use, on 24hr a day
> operation.  Mostly used in audio and switching, like flip-flops, and servo
> amps.  Not RF applications.
>
> According to my old GE -Essential Characterstics- book, c1963, the
> 5814 is listed as a "special 12AU7".  It was also listed as a 5 star 
> product
> from GE, graded for mil-spec applications and the like I guess.
>
> Now the 5814 draws a little more on the filament, 0.175A at 12.6V while
> the 12AU7 is rated at 0.15A at 12.6V.  That would mean you would not
> want to mix them in especially series applications, i.e. 24V mil gear. and
> if you had a lot of them it might burden the filament supply too much.
>
> We used a lot of them in audio chains, old microwave mux gear and some
> mobile applications.
>
> 5814 rated at 2.7 max plate watts, while 12AU7 at 2.75, some diff there
> too.  But major difference is the output capacitance of 0.5uufd for the
> 5814 vs 2.0uufd for 12AU7.
>
> So generally, they are a "direct" sub, but not really.
>
> Rod
>
> ----- Original Message -----
> From: "Dan Pividal" <dpividal at tampabay.rr.com>
> To: "Revcom" <revcom at wbsnet.org>
> Sent: Friday, February 01, 2008 6:04 PM
> Subject: Re: [Heathkit] Question on 12AU7
>
>
>> What type circuits should I avoid Rod?
>> Dan/N4VET
>> ----- Original Message -----
>> From: "Revcom" <revcom at wbsnet.org>
>> To: "Dan Pividal" <dpividal at tampabay.rr.com>; "heathkit at mailman.qth.nt"
>> <heathkit at mailman.qth.net>
>> Sent: Friday, February 01, 2008 6:38 PM
>> Subject: Re: [Heathkit] Question on 12AU7
>>
>>
>> > In most all circuits they will work just fine.  Probably last longer.
>> > Rod
>> >
>> > ----- Original Message -----
>> > From: "Dan Pividal" <dpividal at tampabay.rr.com>
>> > To: "heathkit at mailman.qth.nt" <heathkit at mailman.qth.net>
>> > Sent: Friday, February 01, 2008 10:50 AM
>> > Subject: [Heathkit] Question on 12AU7
>> >
>> >
>> >> Is the 5814A a direct substitute for a 12AU7A?
>> >> I show it is when I go to some tube sub charts.
>> >> I have a bunch of 5814A and would like to know.
>> >> Dan/N4VET
>> >>
>>
>>
>
>