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Old 15th May 2004, 03:29 PM   #1
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Default found two boxes of GE 6CL6 tubes

hi


i found 2 boxes of GE 6cl6 tubes that are mad in usa.


any idea what i can do with them?preamp or amp maybe....


are these rare?these are used mainly for transimitters(i found out on google).what are transmitters?

thanks
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Old 15th May 2004, 05:38 PM   #2
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Take a look at the spec. sheet (http://www.pmillett.addr.com/tubedat...t%201/6CL6.PDF). It's a video O/P tube for TVs and O'scopes.

The 6CL6 has a high 150 KOhm Ra that argues against it being used as a "final" in an audio amp. It would make a DANDY current sink for a cathode follower or a differential amp.

BTW, a transmitter broadcasts radio and TV.
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Old 15th May 2004, 06:35 PM   #3
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Please tell me what pentode plate resistance has to do with output power. Extra credit, tell me the plate resistance of a 12AX7, 6V6 and 31LQ6 at standard audio-use operating points (class A/AB).

6CL6s should work great for drivers of big tubes or output itself. Kinda like a 6BQ5 but a bit less current. I once drew up a design using a sextet in triode mode class AB PP, 20 or 30W output.

Tim
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Old 15th May 2004, 11:45 PM   #4
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Quote:
Please tell me what pentode plate resistance has to do with output power.
Nothing, BUT O/P "iron" for the 6CL6 will be problematic. Ra for the EL84 is about 38 KOhms. The Dyna A-410 trafo, suitable for use with the EL84, has a CT 8 KOhm primary. Custom trafos with CT 32 KOhm primaries are indicated for the 6CL6.

I suppose a quad of 6CL6s substituting for each KT88 with KT88 O/P "iron" would work. 8 bias adjustment pots. per PP channel will be tedious. Obtaining the TIGHTLY matched octets needed for cathode bias seems to be impractical.
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Old 16th May 2004, 02:26 AM   #5
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so these tubes have no use on thier own?you need to get other tubes to make it work?


how about using it in a preamp?can anyone lead me to a diagram?


TY
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Old 16th May 2004, 06:10 AM   #6
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Announcer speaks into a microphone.

- > Microphone converts the air vibrating into an electronic signal by means of a piece of metal moving a magnet over a coil, The magnet pushes the electricity in the wire because electrons are moved in/through metal by magnetisim.

-> The weak magnet and coil inside the microphone is far too weak to excite an antenna so we need to amplify it.

This is where your tube comes in.

-> This slightly amplified signal is now able to excite a larger tube typically called an RF Amplifier tube.

-> The RF tube is most times indirectly connected (coupled) to a large antenna which "Transmitts" this "RF electricity" into the space surrounding the antenna. Then if powerful enough your town and country. (Roughly put).

Theres no way 2.8watts is useful for RF applications of large nature unless you're quite an experienced HAM which is far off in this case. (sorry)

So this tube cannot be used here.

Your radio antenna is excited by the electricity surrounding it.

-> Your Radio Amplifies the signal from the airwaves and then /converts/ it to an AF signal or "Audio signal" for you to hear.
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Old 16th May 2004, 06:23 AM   #7
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Quote:
Originally posted by Eli Duttman
Nothing, BUT O/P "iron" for the 6CL6 will be problematic. Ra for the EL84 is about 38 KOhms. The Dyna A-410 trafo, suitable for use with the EL84, has a CT 8 KOhm primary. Custom trafos with CT 32 KOhm primaries are indicated for the 6CL6.
Ok, power, impedance, whatever, just tell me what it has to do with pentode Rp.

Calculate some operating points on the tubes I listed above. Find plate resistance. I think you'll see the 31LQ6 has Rp higher than a 6V6 yet runs 80W into a 2ka-a load, while 6V6 runs 10W into 10ka-a. These aren't triodes.

Tim
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Old 16th May 2004, 06:36 PM   #8
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Default AB2 maybe

Looking at the GE datasheet for the 6CL6, the plus Grid 1 (AB2) operation region is quite linear. Need to bring the screen G2 voltage down to maybe +90V to get average plate dissipation watts down and use maybe +125V B+. The higher current/ lower voltage operation of AB2 mode will allow a low primary impedance transformer to be used then (maybe 4K plate to plate for two tubes in P-P). Would require a set of cathode followers to drive the grids then.
Paralleling more tubes in AB2 mode would allow even lower primary impedance so that eventually, with enough tubes (about 10 and 10 !!), one could use a dual 120V to 35V line transformer for the output xfmr. Can use G1 grid stopper resistors to help equalize plate currents in AB2 mode too (if always in +G1 region). Some small cathode current sharing resistors would be helpful too.
Sure will look impressive with all those tubes and 75W output.

Don
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Old 18th May 2004, 01:14 AM   #9
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hi,

i can help you with power traffo's and output traffos for these tubes should you require to diy an amp using these tube, power output of about 1watt is possible...

tony
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Old 19th May 2004, 12:11 AM   #10
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6CL6's were used as cathode followers is at least one Fisher amp I can think of,
and IIRC, they were allso used as modulators & outputs on some tube
CB gear.

Any rate, the GE book says with
Va 250V, Vg2 150V, Vg1 -3V
6CL6 will put out about 2.8 W into 7.5K ohms.
7.5K wouldn't be impossible to come up with, actually if
one just wanted to experiment a little the standard issue
5K output used with 6V6's & 6BQ5's would be close
enough for some rock n' roll...
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