Copper Talk » Modifications » Amplifiers » Black cat jb - 12 questions « Previous Next »

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Taz
Posted on Sunday, July 06, 2003 - 7:37 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

umm, why are there no posts here?

This is weird.
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Tech808
Posted on Sunday, July 06, 2003 - 8:13 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Taz,

Checked the Ask The Tech Section (Amplifiers) and No posts there either.

Maybe no one owns one or no one has had problems with one.

Actually I have never seen one myself or known of anyone who had one.

Lon
Tech808
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Taz
Posted on Sunday, July 06, 2003 - 8:37 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Well, the thread was here but no posts inside.


Weird.
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738
Posted on Wednesday, July 09, 2003 - 4:14 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I heard and saw one around 1979, let me tell you I have not heard to many radios sound as well so very loud and clear. The old guy used to come in sounding like he was yelling, on rare occasion from over the Hill. Everybody could not wait to talk to him because he sounded so great. He was driving it with a old tube radio I forget now what it was. I later saw one and as best as I can remember it had one tube, was small, tall, and rectangular with the top 3/4 of it being made of that punched screen type caging. something like 6X4X8" or so. Hope this helps, if I ever see one for sale I will buy it. Hope this is of a little help, It hurt my brain to try to remember so far back so don't shoot me if I goofed on a detail ha., ha...
73
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Crafter
Posted on Thursday, July 10, 2003 - 2:04 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Think It runs a 6gk6 or something Basically the same cabinet as the JB 76 AC power supply. I used mine on my mark 3's. Great little driver.
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Browningboy
Posted on Thursday, July 10, 2003 - 8:05 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

the tube is a 6bq6 or a 6bq5 depends on the series of jb12 you have dudes and they work great i can get you guys an RM 100 now that's like a jb150 has 1 8417 tube in it guy wants 150 for it mint says he gets em NIB I Myself use a jb200a now that's a 2 piece unit with the tubes and power transformer seperate they run 2 8417 tube I key 4 watts into the jb then tune the jb for 3 watt dead key and she swings 3 to 200 watts now how's that for swing and is a modulator not just an amplifier and yes there's a differance
BT634 Browningboy John in R.I.
If you here the north east skip in there give us a shout I'll be in there with my birds
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2600
Posted on Thursday, July 10, 2003 - 8:32 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

The JB-12 uses a 6BQ5 tube, roughly the same size tube used as the final in most tube-type AM CB transmitters. The carrier control in the back should be set for around 2 to 3 Watts carrier. It will typically swing 30 to 40 Watts PEP. 30 years ago, that looked like a lot, compared to the 16 or 18 Watt peaks that a lot of small tube base radios would swing. Too much carrier, and the 6BQ5 roasts pretty soon. Most of the modern "black radio" base stations will deliver as much as the JB-12.

It's still popular with folks who use big amplifiers for setting the carrier level with an old radio that has no variable power control. On the other hand, a DX2517 will deliver roughly the same power as a JB-12, all by itself.

If yours is old enough to have a second, skinnier tube behind the 6BQ5, that is the keying circuit. All that one does is to sense your transmit RF power, and close the relay when you key the radio. Newer ones have a 12-Volt relay and a more modern transistor keying circuit (and only one tube).

73
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Crafter
Posted on Friday, July 11, 2003 - 2:40 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I got a 200a but someone painted it gold But I thought it was a JB76 base unit. Cause the jb76 mobiles I seen were the same basic set-up. My SUPER MODULATOR has a 6bq5 I used to buy them in packs of 5! LOL...

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