Bob,
This is a little different response. I built an almost exact copy of the
DX-811A amp from the Sep 82 CQ magazine. It uses a roller inductor that
only goes to 80M, but it works beautifully--and if you get the exact
resonance point for your freq ( and log it on a vernier dial) you will have
the optimum no compromise output that band switches can not give. I
agree with Jeff that on 10M it is touchy, but I am still happy and still use
this amp today. I have a 30L1 but use the HB amp more because I like the
roller inductor. Other hams I have talked to are positive about the roller
inductor. I'm not sure the MFJ would be good for that much power and
voltage. My two cents.
73
Dale K5AJZ
-----Original Message-----
From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Jeff AC0C
Sent: Sunday, September 25, 2016 6:42 PM
To: amps@contesting.com
Subject: Re: [Amps] MFJ-(AMERITRON) ROLLER INDUCTOR?
Bob,
Been there, done it, wish I had not. A roller ends up giving you a lot of
odd resonance points which can make you just crazy especially on the high
bands. The Q of the roller is generally poor compared to a switched tank.
And while it is working in my amp, I suffer in efficiency as well. It was a
cool idea - especially given my massive square-cut roller should handle MW
of power. The MFJ is going to have more losses as compared to this one.
Unless you absolutely must use a roller, your life will be simpler in the
long run to use a switched tank.
73/jeff/ac0c
www.ac0c.com
alpha-charlie-zero-charlie
-----Original Message-----
From: nemo zilch
Sent: Saturday, September 24, 2016 12:55 PM
To: amps@contesting.com
Subject: [Amps] MFJ-(AMERITRON) ROLLER INDUCTOR?
I am going to build an amp using a single GS-35B, 3800 volts, 600mA. I am
thinking of using the Ameritron roller inductor sold by MFJ. It is on page
86 of their current catalog. It is edge wound, silver plated coil and
contacts, 16uH. It looks pretty heavy duty to me. I would appreciate any
advice re using this inductor for my amp.
Bob W4AOS
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