[AMPS] ? Voltage Doublers as Anode Supplies
km1h@juno.com
km1h@juno.com
Tue, 1 Sep 1998 16:06:00 -0400
On Tue, 1 Sep 1998 09:38:03 -0700 zeitler@ibm.net writes:
>
>-----Original Message-----
>From: km1h@juno.com <km1h@juno.com>
>To: measures@vc.net <measures@vc.net>; amps@contesting.com
><amps@contesting.com>
>Date: Tuesday, September 01, 1998 8:07 AM
>Subject: Re: [AMPS] ? Voltage Doublers as Anode Supplies
>
>
>>
>>Rich's response is right on the mark.
>>
>>It might also help to mention that beside Heath; Drake, National,
>>Kenwood, Hunter, Collins, Dentron, B&W, and Yaesu and probably
>several
>>others used doubler supplies to good advantage. They also work just
>fine
>>on RTTY when derated accordingly.
>>The inherently low resistance of the xfmr,
>
>......is very important. My L-4B stock primary power xmfr has a sec. R
>value
>of around 15 ohms. The no load to full load E drop is only 300 volts
>fully
>loaded for max power out, around 1250 watts on 40 meters with 90 watts
>of
>drive. E doublers work and time proven. QRO and Command Technologies I
>believe are both using doublers.
>
>I HIGHLY recommend Digi_key as a great source for quality electrolytic
>caps
>for the filter bank. I recently pickled up some 560uF 400 volt caps
>that are
>incredibly small for around $10.00 per cap or so. These days we are
>able to
>get a lot of cap for the size.
I would be real cautious with any Digi Key caps Lane. My last catalog of
a year or so ago showed nothing that would be suitable for high ripple
currents as to be expected in a doubler supply. A similar discussion on
suitable caps took place here last year.
They may have something now but Digi Key has never been on my list of
usefull distributors.
My own experience is that only CGS style computer grade and CDE 381LX
series designed for switching supplies have a low enough ESR for the
task. Mouser carries both at decent prices....BTW I would not go above
220MF or so in a 4 high filter stack such as the SB220/L4B etc.
A bonus with quality caps is that the capacitance tolerances are very
close and a 100K 3W metal Oxide resistor is all it takes to equalize
voltages.
>
>OTOH my old Heathkit Warrior that uses a choke input has OUTSTANIDNG E
>reg.
>It will work only on 120 volt mains (using stock plate xmfr) and fully
>loaded the Ep only drops around 175 volts. Currently it is configured
>to run
>(4) 572Bs and will provide around 900 watts out with 90 watts of
>drive. The
>unloaded Ep is only 1650vdc. This shows how good the orig. ps design
>is.
Good design...just not very portable!
I always enjoy the guys bringing in their old 160 pound Henry 2K's and
commenting how great the amp is and then in the next breath asking me to
fix the PS. !!
73 Carl KM1H
Amplifier Repairs and 6M Conversions our Speciality
>
>My two cents worth.
>
>Lane
>KM3G
>Very HOT San Diego
>
>>coupled with sufficient C in
>>the filter allows full load to no load regulation in the order of
>10-15%
>>and significantly better on SSB.
>>
>>I would also suggest to obtain a Dahl catalog and check out the CCS
>>ratings of his wide selection of replacement xfmrs for the above
>>mentioned brands.
>>
>>73 Carl KM1H
>>Amplifier repairs and 6M Conversions our speciality
>>
>>
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>>
>>
>
>
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