Hi All,

I am planning to replace the four 811A's in my AL-811H amp. Is there
anything special I need to do to accomplish this?? I have read about
"burn in" but is there anything else?

Thanks in advance,

Doug W3IIY

"I am planning to replace the four 811A's in my AL-811H amp. Is there
anything special I need to do to accomplish this?? I have read about "burn
in" but is there anything else?

Remove power. Make sure voltage is zero. Remove plate caps on old tubes.
Remove tubes. Put in new tubes. Replace plate caps. Close cover before
striking. Turn power on. Light up cigar.

Colin K7FM

Some amps have neutralization caps that may have to be adjusted when
you change tubes. I think the AL-811H uses a neutralization
transformer and there is no neutralization adjustment, but look in the
manual to be sure.

COLIN LAMB wrote:

"I am planning to replace the four 811A's in my AL-811H amp. Is there
anything special I need to do to accomplish this?? I have read about "burn
in" but is there anything else?


There is no reasone to "burn in" tubes.

In article ,
Cmd Buzz Corey wrote:

COLIN LAMB wrote:

"I am planning to replace the four 811A's in my AL-811H amp. Is there
anything special I need to do to accomplish this?? I have read about "burn
in" but is there anything else?


There is no reasone to "burn in" tubes.

Apart from mercury-vapour rectifiers and thyratrons, of course.

Chris.

--
All software sucks. Everybody is considered a jerk by somebody. The sun
rises, the sun sets, the Sun crashes, lusers are LARTed, BOFHs get drunk.
It is the way of things. -- (Steve Conley)

Chris Suslowicz wrote:
In article ,
Cmd Buzz Corey wrote:


COLIN LAMB wrote:


"I am planning to replace the four 811A's in my AL-811H amp. Is there
anything special I need to do to accomplish this?? I have read about "burn
in" but is there anything else?


There is no reasone to "burn in" tubes.


Apart from mercury-vapour rectifiers and thyratrons, of course.

Chris.

In amps with multiple tubes in parallel it is a good idea to use
matched tubes if possible (you can get matched 811A's). Some amps
have bias adjustments for each tube so you can match idle current
on the tubes (don't think yours does though). IIRC the amertron
4 tube 811A amp DOES have a small neutralazition cap, the 3 tube
one does not. The manual should tell you how to adjust the
neutralization, however in most cases it only matters on 10 meters.

Thanks to all of you who responded.

73, Doug W3IIY

Ken Scharf wrote:
Chris Suslowicz wrote:

In article ,
Cmd Buzz Corey wrote:


COLIN LAMB wrote:


"I am planning to replace the four 811A's in my AL-811H amp. Is there
anything special I need to do to accomplish this?? I have read
about "burn
in" but is there anything else?


There is no reasone to "burn in" tubes.



Apart from mercury-vapour rectifiers and thyratrons, of course.

Chris.

In amps with multiple tubes in parallel it is a good idea to use
matched tubes if possible (you can get matched 811A's). Some amps
have bias adjustments for each tube so you can match idle current
on the tubes (don't think yours does though). IIRC the amertron
4 tube 811A amp DOES have a small neutralazition cap, the 3 tube
one does not. The manual should tell you how to adjust the
neutralization, however in most cases it only matters on 10 meters.