The AM Forum

Now I just have to figure out what to do with the Phantom 500 11 meter amp I got for $20 at Axeman; four 6LQ6s driving eight 6LQ6s in parallel!

I suppose the tubes are worth more than I paid, although I haven't checked them yet. From what I've seen on the web I should just convert it to a couple of 811s or scrap it for the parts, it's got three power transformers in parallel! Nothing looks cooked and it looks like the power transformers are Stancor P-8339s. The tubes are all 6LQ6/6JE6C Raytheons and look unburned.

(http://img444.imageshack.us/img444/6114/img6481il3.th.jpg) (http://img444.imageshack.us/my.php?image=img6481il3.jpg)

(http://img252.imageshack.us/img252/8735/img6500vo8.th.jpg) (http://img252.imageshack.us/my.php?image=img6500vo8.jpg)


Any ideas?

If you have the test equipment, I'd be really curious to see the specs on this, since it's a typical "afterburner" cb amp. I've always been curious how those things perform, and if there's any value to them for ten or other ham bands.

73,

Bill W1AC

It'd be interesting to see what it would do as is, although I think I'd change the filter caps first. The thing is a switching nightmare, three relays and one tube to key everything.

It turns out that the three power transformers are Stancor 8339s, 650 volts ct @255ma, 12.6 vac ct filament windings, and 5 vac @ 3 amps which is unused. Someone had scratched P-8590 on the tops of the transformers which led me wrong. They're listed as TV transformers in the 1959 Allied catalog.

It may work to pull the four driver tubes and the two output tubes furthest from the fan which would give me room to install a good 80-10 pi output. From what I hear it's hard to get a good tuning with all 8 outputs in it with all the tube paralleled, at least on 10, it might be better on the lower bands.

(http://img340.imageshack.us/img340/308/phantom500uy9.th.jpg) (http://img340.imageshack.us/my.php?image=phantom500uy9.jpg)

Here is a link to the same schematic (PDFs) and a redrawn one of a 250 Maverick which is pretty much the same except for one less transformer, 4 less outputs and the driver tubes are a different type; but it's easier to read.

http://f1.grp.yahoofs.com/v1/8AolSeTHQdXYl1e3AWKArYJjykHihXGFjExfGAZlzp6fbRoIuHCBQGRuI8KIyAVLCn4bs-7BfYDgM1f9nyQsmuSq5ilmRQ/D%20%26%20A%20amplifiers/D%20and%20A%20%20extra%20schematics.pdf

Use it on 10 meters as is.
One of those 10 meter mono banders can be had at flea markets for a decent price.

What else but, MAKE IT SWING!

I'd be interested in learning what you decide to do with it. I've been considering getting something along these lines and pretty much gutting it, keeping the power xfmrs, chassis, and whatever else might be useful as a foundation of a homebrew 160-40 amp using maybe a couple of 811s or similar like you say.

If cheap enough it might be worth it vs staring from scratch.

73, Mark

With all those tubes you could rip it apart and build a series modulated hi-fi rig for 75 and 160.

I wonder what the plate impedance of the output stage is...All those Low-Z toobs in parallel.
Designing a multiband Pi-network for it might be an interesting exercise.

Bill,

Remember the Galaxy 2000 (the "real" WRL Galaxy and not the new Chinese excrement) designed to match the old Galaxy III and V line of transceivers?  Ten 6HF5 tubes in parallel with a very low plate load impedance.  Downloading the manual for that would probably be a good start for anyone who wants to try a lot of sweep tubes in parallel.

Rodger WQ9E

That looks like a meam MO-JO-MO-FO

Fred

You need artwork

I'll have to add that to the front!

There is a design that look promising in the 1972-3 ARRL handbook (available on line) that uses four 6KD6s and plug in coils for a link coupled output for 800 watts PEP. This could probably be adapted to six 6LQ6s which would give me a spare set assuming all the tubes in the set are good.

Lots to think about.