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

[Al Klase]

Yardleyite at aol.com wrote:
> 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. 

Hi Joe,

I wouldn't expect you'd hurt the 112A.  They're both rated 
for 180 volts on the plate, and the 71A circuit will most 
likely have more grid bias than the 112A wants to see, but 
that will just limit plate current and cause some distortion.

Al


-- 
Al Klase - N3FRQ
skywaves at webex.net
Flemington, NJ 08822
Web Page:  http://www.webex.net/~skywaves/home.htm