3-400's
 

Would 3-400's be exact replacementsfor the 3-500's in my L4B?

Thanks for your help!

Fred
W4FCM

3-400's
 

On Mar 25, 5:25*am, Fred Cameron wrote:
Would 3-400's be exact replacementsfor the 3-500's *in my L4B?

Thanks for your help!

Fred
W4FCM

If you will go to eHam.net there is some good info on using 3-400 &
3-500 tubes . I have owned several Drake L4B amps,all with 3-500
tubes ...I seem to remember seeing L4 `s with 3-400 tubes..I don`t see
any problem with changing from 3-400 to 3-500 If all(except fil )
pins are grounded .. GL W4PQW

3-400's
 

On Mar 25, 6:25*am, Fred Cameron wrote:
Would 3-400's be exact replacementsfor the 3-500's *in my L4B?

Sometime in the 60's, Eimac stopped selling 3-400's and instead sold
the "upgraded" 3-500's as drop-in substitutes with higher dissipation.

I don't believe that 3-400Z's have been sold since the early 70's...
of course someone might have them sitting on the shelf.

Most of the electrical parameters are similar between the -400 and
-500 but of course the -500 has more dissipation. The intended path
was that folks would put 3-500's in place of 3-400's - there were some
slight physical changes and I think the 3-500's are supposed to use
beefier anode clips etc but many amps using 3-400's just had 3-500's
put in with no changes. I think the L4B originally had 3-400Z's.

Tim.

3-400's
 

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