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RCA 5762/7C24 Tubes




----------
From:  djQuecke [SMTP:djQuecke-at-worldnet.att-dot-net]
Sent:  Wednesday, June 03, 1998 9:45 PM
To:  R W Stephens; Tesla List
Subject:  Re: RCA 5762/7C24 Tubes

I know zero about tubes but have wanted to learn more for some time.  I came
across a box full of tubes in a dumpster a while back after some ancient
electronic gear was replaced.  I have absolutely no clue on the tube
numbering system but I have quite a few 5763 tubes.  Are these "close" to
the 5762s discussed in your message?

After I dug this box of tubes out of the trash (still in original boxes,
mostly Sylvania and RCA), I priced some of them on the 'net and was floor by
their value.  Many are Mil spec.  I'm sitting on a small gold mine and would
like to learn what the usefulness may be.  (There were quite a few 6550s and
12AX7/12AT7s also and I hope to build a couple of amplifiers for my
daughter's band <g>).

A Tube TC has been on my list of things to check into but I have no 8xx
series tubes.  Is there a 'net resource where I can learn what type of tubes
I have?  So far I found info on only a few.

Thanks,

dj

-----Original Message-----
From: Tesla List <tesla-at-pupman-dot-com>
To: 'Tesla List' <tesla-at-pupman-dot-com>
Date: Monday, June 01, 1998 9:26 PM
Subject: RCA 5762/7C24 Tubes


>----------
>From:  Robert W. Stephens [SMTP:rwstephens-at-headwaters-dot-com]
>Sent:  Monday, June 01, 1998 5:57 AM
>To:  Tesla List
>Subject:  Re: RCA 5762/7C24 Tubes
>
>
>> ----------
>> From:  Pete [SMTP:casius-at-cyberserv.co.za]
>> Sent:  Monday, June 01, 1998 11:55 AM
>> To:  tesla-at-pupman-dot-com
>> Subject:  RCA 5762/7C24 Tubes
>>
>> Hi to all,
>>
>> Has anyone out there had any experience with the RCA 5762 / 7C24
>> transmitting tube. I believe it to be a triode capable of 5kW. By the
>> size of the tube I guess that the household wiring would not be able to
>> support the power supply.
>>
>> Regards
>> Pete
>
>Pete, All,
>
>The RCA 5762 triode is a terrific tube for a largish vac toob TC if
>you can get your hands on one or more!
>
>Fil.  12.6 V -at- 29 A
>Amplification Factor 29
>Plate Volts Max 6200
>Plate Dissipation Max 3000 Watts
>
>Used as a self rectifying oscillator (as in Tesla coil with mains AC
>on the plate supply, or an industrial heating oscillator) the RCA data
sheet
>has the following advice:
>
>Maximum Ratings
>----------------------
>AC Plate Volts (RMS)... 7,000 max. volts
>DC Grid Voltage...-300 max.volts
>DC Plate Current...0.625 max. amps
>DC Grid Current...0.135 max. amps
>Plate Input...4,900 max. watts
>
>Typical Operation
>----------------------
>AC Plate Voltage (RMS)...6,600 volts
>DC Grid Voltage...-127 volts
>DC Plate Current...0.625 amps
>DC Grid Current...0.105 amps
>Driving Power (approx.)...60 watts
>Power Output (approx.)...3,350 watts
>
>The thoriated tungsten filament has a center tap which should not be used
>for heater current but is offered as an extra place to add a bypass
>cap to ground when the tube (good for up to ~220 MHz) is used at
>higher frequencies.
>
>I have canibalized two RCA BTA-10K AM broadcast transmitters which
>originally came outfitted with 5 of these RCA 5762 tubes each.  A pair in
>push-pull as the modulator and three tubes paralleled for the RF final.  My
>transmitters came with an English Electric Valve higher performance
>direct replacement of this old RCA tube which are rated at a
>considerably higher 5 kW of plate dissipation.  I am using three of
>these newer EEV BR1160 triodes in parallel in my Coronatron (hi-power
>vac toob TC).
>
>The RCA or EEV tubes have an external copper finned jacket anode about 5
>inches in diameter which sit (fil. end up) in a special spring
>fingered socket cup which is pressurized by a high CFM blower.  A
>second cooling air nozzle must be directed sideways and downwards
>directed at the filament terminals coming out of the top (fil. end)
>of the tube to keep the seals cool.  To insure long service life
>ALWAYS allow 5 minutes of filament warmup time before applying plate
>current!  Once they are up to temperature the filaments should be
>left on if the unit is to stand idle with plate supply off for up to
>several hours and then be re-used.  These tubes require serious
>airflow at max ratings.  I'd recommend about 1/3rd to 1/2 horsepower of
>turbine blower per tube.
>
>Normal wimpy house wiring (except 230 volt stove or dryer circuits) won't
>fully excercise this tube but if you wire your project directly to the main
>panel you should be able to have some *serious* fun! : )
>
>Good luck.
>
>Robert W. Stephens
>Director
>Lindsay Scientific Co.
>RR1 Shelburne, ON Canada L0N-1S5
>Tel: 1-519-925-1771   Fax:
>*Custom built Tesla coils, etc., for museum display
> and special effects work.
>*Canada's largest publicly accessible wall-to-wall
> indoor lightning show...by appointment.
>*Future home of Electric Science World,
> educational/entertaining Theatre of Electricity.
>*Antique TV Museum...in search and acquire mode now.
>~~~~~~~~~~~~~ Inquiries welcomed! ~~~~~~~~~~~~~~~
>