Re: L7 input coil ajustment
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Ooops...sorry Paul....I wrote that very poorly and didn't pick it up in the proofread!
Actually, while nichrome parasitics?WERE removed from that amp (and I made my own copies of the originals to replace them), there were other mods in the input circuit that were also removed.? Paul's ESAC-Harbach all-in board was installed in the amp and it is THAT I was referring to.? I have?been a strong proponent of Paul's products for many years.? My statement was never meant to cause any misunderstanding?or harm.
Again....sorry Paul!
73 Peter VE7PS
On Mon, Jan 15, 2024 at 1:07?PM Paul Kraemer < elespe@...> wrote:
For the record? I have NO parasitic suppressors new or old for
ANY amplifier.
For the record.
Apology forthcoming?
Paul K0UYA
On 1/15/2024 2:53 PM, VE7PS wrote:
Howard:
I'll add two comments to David's instructions for adjusting
the input tuning on the L-7
1)? Check out the L-4B instructions.? They got that correct
and it's the same procedure.
2)? While I would not personally recommend
adjusting the input tuning with high voltage applied...for
safety reasons...but?IF you choose to do so,
keep in mind you would also have to defeat the HV
interlock to do this with the lid off....which IS
necessary to reach the coils.
I recently did some work on an L-4B for a ham in Surrey,
BC.? I did the input tuning on his amp after undoing some
"magic nichrorme" mods and adding in some more modern ones
(Electronic Specialties).? Note the input tuning is very
broad, though perhaps due to aging of the caps, I did notice a
slight improvement on some bands.? As such, I am not in any
hurry to adjust the input tuning on my own amps, unless
perhaps the tubes get changed at some point.
Be careful!
73
Peter
VE7PS
Hey guys, I'm going to be doing
a input coil adjustment on my L7 amp. Eimac tubes are getting
very soft and I'm replacing them with RF Parts matched pair.
I've done this before and i'm very aware of safety procedures.
It's been awhile.
I just want to clarify a few things before I start. Procedure
(F) I take it that the plate control should also be in the
centre of the band I am adjusting , this is not mentioned in
procedure. Also when increasing exciter output to achieve a
.400 amp. reading on the grid meter, procedure (I) is this
correct because my other L7 manual said plate meter.
Lastly when tuning the plate control for dip in plate current,
procedure (J) is it a greatest dip possible or just a slight
dip in plate current??
Thanks for any input you can provide. Howard VE7IGA
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