Re: [Amps] SELL: Mint Drake L4B amplifier Package

[Paul Baldock <paul@paulbaldock.com>]

At 11:10 AM 5/7/2016, you wrote:
> The Drake L4B RF deck easily turns into an Al-82 amplifier with the 
> same power transformer in the power supply.  1500 watts output no sweat.
How do you get away with the same power transformer? Hopefully not by 
increasing the primary voltage.
On my sample of 1, the original power supply gives about 2600V. To 
get to 3400V no load I built a second supply of about 800V DC 
(actually switchable to 0V, 400V and 800V), and place this in series 
with B-, which means the original 2600V floats above ground by 800V, 
but other than that the original supply is not under any additional 
stress. I also added real bias to limit idle current to around 140mA. 
I am still using the original fan, but I'm sure the amp could use 
more air flow. I have a built in timer to cause the fan to run for 30 
seconds after the amp is turned off.
- Paul  KW7Y



> -----Original Message-----
> From: Paul Baldock <paul@paulbaldock.com>
> To: Jim Garland <4cx250b@miamioh.edu>; amps <amps@contesting.com>
> Sent: Sat, May 7, 2016 10:26 am
> Subject: Re: [Amps] SELL: Mint Drake L4B amplifier Package
>
> I've moded my power supply for 3150V under load, and can get 1500W
> PEP. But standard 1200Ws typical.
>
> - Paul KW7Y
>
> At 09:39 AM 5/6/2016, Jim Garland wrote:
> >Ron, how do you get "legal limit ++" out of an L4B? I've owned several of
> >them and get only 1200-1300W output, measured on accurately calibrated
> >wattmetes. My latest one has the same mods (new caps, diodes, etc.) as
> >yours.
> >73,
> >Jim W8ZR
> >
> > > -----Original Message-----
> > > From: Amps 
> [<mailto:amps-bounces@contesting.com?>mailto:amps-bounces@contesting.com] 
> On Behalf Of
> ><mailto:w2cqm@juno.com>w2cqm@juno.com
> > > Sent: Thursday, May 05, 2016 5:30 AM
> > > To: <mailto:amps@contesting.com>amps@contesting.com
> > > Subject: [Amps] SELL: Mint Drake L4B amplifier Package
> > >
> > > Reducing inventory and offering a full output, near mint, vintage,
> >all
> > > original, Drake L4B amplifier and OEM power supply. Has brand new RF
> >Parts
> > > 3-500Z&rsquo;s personally tested and running full output legal limit ++.
> >Super quiet
> > > fan. Has had new power supply filter caps and diodes installed; however,
> >will include
> > > the new, never used, partially completed, Harbach compact rectifier board
> >subsequently
> > > purchased to further upgrade the aesthetic component of the supply. From
> >the digital,
> > > it&rsquo;s evident that the board has the capacitors already installed
> >(needs diodes)
> > > and ready to drop in. The amplifier is clean with no bangs or dents. All
> >controls and
> > > meters are fully functional. Will include the special two prong antenna
> >changeover relay
> > > plug with the RCA male plug on the exciter end as well as an original,
> >pristine Drake
> > > manual with all foldout schematics. No creases, tears, or pencil margin
> >notations
> > > other than &ldquo;SHOP&rdquo; (unfortunately) printed on the front
> >cover in black
> > > marker. Asking $1150 pick up ONLY in the Scranton,
> > > PA area or in the Freehold,New Jersey area when frequently visiting with
> >the children.
> > > If preferred, I can arrange for a convenient Dayton Hamfest pickup at
> >my
> > > cousin&rsquo;s tailgate location. A rare opportunity to 
> purchase an L4B is
> > > excellent, original condition. Ron W2CQM/3 Currently listed with
> >digital on
> > > QTH.COM
> > > ____________________________________________________________
> > > StyleBistro
> > > The Royal Family Was Shocked When Kate Wore This
> > > 
> <http://thirdpartyoffers.juno.com/TGL3141/572b2ec97f0db2ec908d3st02vuc>http://thirdpartyoffers.juno.com/TGL3141/572b2ec97f0db2ec908d3st02vuc
> > > _______________________________________________
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