Am sure there is stuff on this in the Amps archives.
Years back I had an L-4.
The original power supply is feeble.
Built it a new one giving around 3.3kV no load.
Cannot remember the numbers, but output much higher and no problems with
flashovers etc
Also fitted a 5:1 drive to the Tune control.
It was very nice.
Only sold it because I bought an amp that covered 160 as well at bargain
price.
73
B
end
Barry Kirkwood PhD ZL1DD
Signal Hill Homestay
66 Cory Road
Palm Beach
Waiheke Island 1240
NEW ZEALAND
ph/fax 64-9-372-5161
www.waiheke.co.nz/signal.htm
----- Original Message -----
From: "R_Davis" <WD8JJA@arrl.net>
To: <amps@contesting.com>
Sent: Friday, March 26, 2004 1:02 PM
Subject: Re: [Amps] Re: Drake L7 newbie
> Good question!! I hope the answer appears on this reflector so all may
see.
>
> I never got around to getting an amp until after the new power limit was
> effective, and then only got a 2x 572B amp. Looking "down the road", when
I
> might upgrade to a higher power amp, I will probably go for an older, 2KW
> model, such as the L-7B or TL-922, for an increase of about 3 dB and add
160
> meter capability. (Seems like the best dB/$ in lieu of the price of a
> brand new amp. )
>
> I know that the older amplifiers were marketed when the power limit in the
> USA, for amateur use, was 1000 watts DC input, instead of 1500 watts PEP
> output. And back then, one tuned the amplifier in reduced voltage mde
(CW,
> TUNE, however it is marked) for 1000 watts input (plate V x plate I). Then
> switched to high voltage for SSB. This was supposed to result in still
> having 1000 watts average, or DC, on SSB, but with much greater PEP.
Hence,
> 2000W PEP input.
>
> Given todays higher output power limits, can these pre - 1500W limit
> amplifiers be tuned up in high voltage or SSB mode for c. 1300-1400 watts
> out (whatever they will do, up to 1500 watts)?
>
> Rick, WD8JJA
>
> ----- Original Message -----
> From: "Thomas R. Williams" <n2cu@magtrol.com>
> To: <amps@contesting.com>
> Sent: Thursday, March 25, 2004 8:24 AM
> Subject: [Amps] Re: Drake L7 newbie
>
>
> Got the amplifier yesterday. What a beauty! I purchased it on eBay from
> someone who advertised it as brand new, never used. It was exactly that.
Not
> a scratch or speck of dust anywhere, and the Eimac 3-500's looked like
they
> just came off the assembly line. Not bad for a 24 year old amp.
>
> The L7 uses rather low plate voltage from what I read about in other
> handbooks; 1760 V at 0.565 A. This works out to about 1 kW input power and
> about 600 Watts output. I know this is the published rating for this
> amplifier, but my little SB-201 puts out the same power with a pair of
> 572B's. I would think that the amp is capable of more, and the rating was
> put on it to be conservative. In the SSB mode, the plate voltage is 2400
V.
>
> Now for my questions. What are users of this amp typically running it at
and
> is 600 W output all I should expect on CW? Can higher voltage be used
> without exceeding the ratings of the tubes or amp itself?
>
> 73,
> Tom N2CU <><
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