[NJARC] Audio Tube Substitution Question: ( a 112A for a 71A ) ???

[Lawrence G. Pryduluk]

To replace tube 71A use 71* or 71B*
* Parallel-filament circuits.
Hope this info helps.

Thanks,
LG Pryduluk
Sparta, N.J.
----- Original Message ----- 
From: <Yardleyite at aol.com>
To: <njarc at mailman.qth.net>
Sent: Tuesday, October 05, 2004 1:41 PM
Subject: [NJARC] Audio Tube Substitution Question: ( a 112A for a 71A ) ???


> Hello All,
>            Could  anyone in our group answer a question I have regarding a
> substitute for a  71A tube? Has anyone ever subbed a 112A for a 71A? The
> pinouts appears to  be the same, the filaments have different ratings 
> (.25A for the
> 112A and .5 for  the 71A) since one tube was designed for a battery set, 
> and
> the other  for AC.
>
> I recently acquired an old  AC TRF set missing it's last audio tube  (71A)
> among others. I had everything else except the 71A. I do however, have a 
> 112A I
> could use in it.
>
> Sometime ago I acquired an Atwater Kent model 67 (DC  set) that calls for 
> a
> pair of 71A's in the last stage of it's  audio. The way I got it the set 
> had
> 1ea. 71A and 112A in it's last audio stage.  Since I've yet to power up 
> the AK
> 67, I don't know if it'll work. Rather than  possibly destroy a perfectly 
> good
> 112A I was wondering if anyone could tell me  if the two are 
> interchangable?
> Any advice will be appreciated.
>                                                                    Best
> Regards,
>
>          Joe  Cro N3IBX
>
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