A single band amp, 3-500z glass tube - that's not even a beginners
challenge by comparison. the Cout is about 7x higher plus the monster anode
on the YC156 makes a hell of a good capacitor with the enclosure where the
effect on a glass tube is token.
When you hang the L on the YC156, you get releif on 10m (for example) but it
pushes the Cin zero point on the pi-net down in frequency so that you may
get it working on 10m but now it's marginal on 12m and you have a monster Q
on 17m.
The bottom line is a YC156 makes a great beginners project for the low
bands. But if you want to make it work on the top end, my advice is to pick
another tube and save yourself a mountain of hours. Despite the somewhat
higher costs, it's actually pretty hard to beat an 8877 with a grid
protection circuit as a limit-capable all band tube when you consider the
entire project.
73/jeff/ac0c
www.ac0c.com
alpha-charlie-zero-charlie
-----Original Message-----
From: Bill Turner
Sent: Tuesday, May 23, 2017 10:03 PM
To: Amps group
Subject: Re: [Amps] new amp race
------------ ORIGINAL MESSAGE ------------(may be snipped)
On Tue, 23 May 2017 20:16:38 -0500, you wrote:
Uh huh. There is Cout that is manageable -- and then there is the YC156.
I
am pretty sure that anyone who has actually been-there, done-that with this
tube - would use the term "easily" in conjunction with the work needed to
make that tube and the upper bands play together.
73/jeff/ac0c
REPLY:
I admit I have not applied the L-network fix to that particular tube,
but I have done it with a Heathkit SB-1000 modified for six meters and
was able to use the original HF tuning cap. Slick.
As for how "easy" it is, all that's needed is a coil of about .5 uH
inserted in the anode lead. That's it.
73, Bill W6WRT
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