Noone has raised the issue of how long 6JB6s last.

If they are used with caution they last for a long time, but if one =
tries to squeeze the last watt out of them (and the 6JB6s invite you to =
do so, thanks to their strong cathode emission) they can last for a VERY =
short time.

The 6146 have a lower cathode emission and do not then lend themsleves =
to be squeezed so badly as the 6JB6s. So there is less harm to =
inadvertently destroy them.

To my experience the Sylvania 6JB6s (those sold by Drake as spares) =
perform better than the GE 6JB6s, and are are easier to neutralize. The =
RCA 6JB6s, luckily much less common, were no good.

73

Tony, I0JX

------------------------------------------------------
Antonio Vernucci, I0JX US call: K0JX
50-MHz beacon: 50.004 KHz FSK 10W 5/8 vertical antenna
home page: http://www.qsl.net/i0jx
e-mail: k0jx {at} amsat {dot} org
------------------------------------------------------
"RadioGuy" ha scritto nel messaggio =
...
The thought came to me the other day whle thinking about the cost of =
6JB6's
nearly $100 for a set; I paid $18.00 for a matched set of three at =
AES back
in the 1970's and I got plenty of spares. Why did Drake use those =
cheap ass
sweep tubes in their final instead of the old standard 6146 to begin =
with?
=20
Sure, back then it seemed in vogue to use sweep tubes in amateur gear =
(yea,
sure, Swan gear...) but as I recall, we thought that Drake was kinda =
cheesy
to use those tubes anyway. I gonna stick my neck out and say Drake
engineering wasn't the end all that the youngsters think nowadays.
=20
(Yes... I have a complete Drake station (including amplifier)---the =
whole
line-up in pristine, vitrually unused condition in crisp factory =
cartons
including accessories, catalogs and a handful of the right-angle =
Switchcraft
microphone (black cap) and key (red cap) plugs that Drake originally
supplied not that PL-whatever. Original owner---me---so it's not sour
grapes.)
=20
RG
=20

Antonio Vernucci wrote in message
...
Noone has raised the issue of how long 6JB6s last.

If they are used with caution they last for a long time, but if one tries to
squeeze the last watt out of them (and the 6JB6s invite you to do so, thanks
to their strong cathode emission) they can last for a VERY short time.

The 6146 have a lower cathode emission and do not then lend themsleves to be
squeezed so badly as the 6JB6s. So there is less harm to inadvertently
destroy them.

To my experience the Sylvania 6JB6s (those sold by Drake as spares) perform
better than the GE 6JB6s, and are are easier to neutralize. The RCA 6JB6s,
luckily much less common, were no good.

73

Tony, I0JX

Absolutely Tony... I share the same experiences as you. I've recently
listened to the youngsters getting their hands on the Drakes but not knowing
how to tune the pi-network with the consequence that they destroy the 6JB6's
in short order---and having to put out $100 for another set. Those sweep
tubes weren't very forgiving... If I remember, we never really worried
about hurting the 6146's as they seemed to keep on working. Furthermore,
correct me if I am wrong, I don't think we ever considered having matched
6146's like we did with the sweep tubes.

RG