hi guys,

im pretty new at tubes, so bear with me.

As far as i understand, the ECC83 is a 12ax7.
Also a ECC85 is a 12at7

I know that you ccan sub 12at7s for 12ax7s in guitar amps, but is it safe to
do in the tuning section of a noremende isablla radio?

thanks, alex

"A Doc" ..


As far as i understand, the ECC83 is a 12ax7.
Also a ECC85 is a 12at7


** Wrong - an ECC81 is a 12AT7.


I know that you ccan sub 12at7s for 12ax7s in guitar amps, but is it safe
to
do in the tuning section of a noremende isablla radio?


** The ECC85 has a 6 volt heater so it not a plug in substitute for
either the 12AX7 or ECC81.



............ Phil

A Doc wrote:

hi guys,

im pretty new at tubes, so bear with me.

As far as i understand, the ECC83 is a 12ax7.
Also a ECC85 is a 12at7

I know that you ccan sub 12at7s for 12ax7s in guitar amps, but is it safe to
do in the tuning section of a noremende isablla radio?

Probably a 12AX7 cannot replace a 12AT7 in an RF circuit.
The 12AX7 has much lower transconductance, and high Ra
compared to the 12AT7.

Patrick Turner.



thanks, alex

A Doc wrote:

hi guys,

im pretty new at tubes, so bear with me.

As far as i understand, the ECC83 is a 12ax7.
Also a ECC85 is a 12at7

I know that you ccan sub 12at7s for 12ax7s in guitar amps, but is it safe to
do in the tuning section of a noremende isablla radio?

thanks, alex

BTW, ECC85 is a 6AQ8, which is a 6 volt version of a 12AT7,
so it has incompatible heater connections compared to
12AX7.

Patrick Turner.

Patrick Turner wrote:


BTW, ECC85 is a 6AQ8, which is a 6 volt version of a 12AT7,
so it has incompatible heater connections compared to
12AX7.


The ECC85 is a 6.3V heater tube, in the same ballpark as the 12AT7, but it
dispenses with the centertap for a shield between the sections.

http://www.mif.pg.gda.pl/homepages/f...01/e/ECC85.gif

Regards,
Kimjand

On Tue, 25 May 2004 23:40:59 -0400, A Doc wrote:

hi guys,

im pretty new at tubes, so bear with me.

As far as i understand, the ECC83 is a 12ax7.
Also a ECC85 is a 12at7

I know that you ccan sub 12at7s for 12ax7s in guitar amps, but is it safe to
do in the tuning section of a noremende isablla radio?


http://www.eierc.com/rc/ECC81.htm
http://hereford.ampr.org/cgi-bin/tube?tube=ECC85

ECC85 is a miniature high-mu twin triode with a 6.3v 0.435A heater. This
isn't centre-tapped like the other small ECC valves. Pin 9 is connected to
an internal screen instead. Personally, I wouldn't attempt to swap them in
an RF application unless I was desperate!

Incidentally, ECC81 is 12AT7, ECC82 is 12AU7, ECC83 is 12AX7.

--
Cheers...
Mick
Gave up on viruses & trojans - moved to Linux... :-)
Nascom & Gemini info at http://www.nascom.info