A subject got sidetracked a while ago, with numerous people getting
nostalgic about the boxes of old 807's they had sitting around waiting
to be used - has anyone built a HF linear using these things - and not
QRP or max 100watts - found one reference to 4 of them in // giving
250 watts - getting there , but a bit more power out, perhaps? - any
pointers to info or sites - there MUST be a use for these things, I
have been hoarding them for 30 years now!
73 de VK3BFA Andrew

"Andrew VK3BFA" wrote in message
om...
A subject got sidetracked a while ago, with numerous people getting
nostalgic about the boxes of old 807's they had sitting around waiting
to be used - has anyone built a HF linear using these things - and not
QRP or max 100watts - found one reference to 4 of them in // giving
250 watts - getting there , but a bit more power out, perhaps? - any
pointers to info or sites - there MUST be a use for these things, I
have been hoarding them for 30 years now!
73 de VK3BFA Andrew

About 25 years ago a place was maiking 27 mhz CB amplifiers using them in
combinations of 4 to 12 of the 1625 tubes, the 12 volt version of the 807.
They would put out about 25 watts of carrier for each tube used. The
circuit used was push pull. It seemed to be a copy of a design in a very
old QST (maybe a 50's version ) design . I don't know how clean the output
was but the amplifier sounded fine on the receiving end. I would guess that
for ssb you could push the output to 3 or 4 times this ammount.

You're kidding, right?

The 807 was the most-used amplifier tube in history. It still beats the
6146 in popularity, given the time it was used. From audiophile tube amps,
to RF modulators to RF linears and class-C self excited power oscillators,
the 807 was/is there :-)

RF schematics are all over. Check Google, check the ARRL Handbook, CB
websites and pirate radio websites.

Russia and China still make it. Russian ones are the best and called
G-807.

If you want to play with an 807 at audio, for all practical purposes, it's
a 6L6GC ;-)

--
Gregg t3h g33k
"Ratings are for transistors....tubes have guidelines"
http://geek.scorpiorising.ca

Gregg wrote:
You're kidding, right?

The 807 was the most-used amplifier tube in history. It still beats the
6146 in popularity, given the time it was used. From audiophile tube amps,
to RF modulators to RF linears and class-C self excited power oscillators,
the 807 was/is there :-)

RF schematics are all over. Check Google, check the ARRL Handbook, CB
websites and pirate radio websites.

Russia and China still make it. Russian ones are the best and called
G-807.

If you want to play with an 807 at audio, for all practical purposes, it's
a 6L6GC ;-)

There are MANY variations on the 807. The 807 is actually a 6L6G with
a plate cap. The 6L6GC has a bit more plate rating than the 6L6.
The 6BG6G/6BG6GA sweep tube is an 807 with an octal base, minus some
sheilding.
The 1625 is an 807 with a medium 7 pin base and a 12.6 volt heater.
The 807W is a smaller squat glass version of the 807 that is more
rugged. It can be pushed harder.

Some 1625's and 807's had the beam deflection plates (suppressor)
brought through the glass with their own wire lead connected to
the cathode at the base. You can debase these tubes and connect the
suppressor to it's own pin (1625) or tie it to one of the
grids (807) and then run the tube in true grounded grid operation.
There were quite a few linears in the 50's built this way.

I recall one amp used a voltage quadrupler to get 600 volts from
the 120v ac line and had 10 tubes with the heaters wired in series.
One tube was a driver, and 9 were grounded grid finals.
(A bit of a shock hazzard perhaps.)

In article , Andrew
VK3BFA wrote:

A subject got sidetracked a while ago, with numerous people getting
nostalgic about the boxes of old 807's they had sitting around waiting
to be used - has anyone built a HF linear using these things - and not
QRP or max 100watts - found one reference to 4 of them in // giving
250 watts - getting there , but a bit more power out, perhaps? - any
pointers to info or sites - there MUST be a use for these things, I
have been hoarding them for 30 years now!
73 de VK3BFA Andrew

The thing that immediately pops to mind about an old 807-based
push-pull parallel amp (6 tubes) was that it was a #$!!*% to
neutralize!

--
Namaste--

artie wrote:
In article , Andrew
VK3BFA wrote:


A subject got sidetracked a while ago, with numerous people getting
nostalgic about the boxes of old 807's they had sitting around waiting
to be used - has anyone built a HF linear using these things - and not
QRP or max 100watts - found one reference to 4 of them in // giving
250 watts - getting there , but a bit more power out, perhaps? - any
pointers to info or sites - there MUST be a use for these things, I
have been hoarding them for 30 years now!
73 de VK3BFA Andrew


The thing that immediately pops to mind about an old 807-based
push-pull parallel amp (6 tubes) was that it was a #$!!*% to
neutralize!

Cross over neutralization circuit should be simple
to set up. A six tube 807 circuit should have about
the same g-p cap as say a 2 tube 811A setup, though
a bit more output C (would be absorbed into the tank
though). Trick with 807's is to sub mount the tubes
below the chassis so the bottom of the plate
is just a hair above the chassis. This lets the chassis
serve as a shield between the plate and the grid circuits.
Millen sold a tube shield for the 807 that would do the
same thing with the socket mounted at chassis level.

....nostalgic about the boxes of old 807's they had sitting around waiting
to be used - has anyone built a HF linear using these things - and not
QRP or max 100watts ....

I can't find it right now, but somewhere I have an article from a ham
magazine that used TEN of them (actually 1625's), with their filaments
series'd across the 120-volt mains and their outputs paralleled on one
of the lower ham bands.

I, too, have been saving them and will find the round tuit someday.

--Myron.
--
Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge
PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785) 539-4448
NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol)

On Thu, 16 Sep 2004 07:40:25 -0700, Bill Turner
wrote:



The problem with 807's is that having only a 25 watt plate dissipation
rating and running a pair in a linear with about 66% efficiency, you're
only going to get out about 100 watts. Today's generic transceiver
already puts out that much, and if you're looking for an HF "brick" for
a QRP rig, solid state is a better way to go.

On the other hand, a nostalgia-driven project could be lots of fun.

Back in the olden days they were a useful tube, but not so much anymore.
Too bad.

the more important limiting parameter for application as ssb linear
amplifier is max cathode current.

It could be mentioned that 4-65 has the same max PEP input as 4-125
because the cathodes are the same

-jm
---
J. M. Noeding, LA8AK, N-4623 Kristiansand
http://home.online.no/~la8ak/c.htm

Gregg wrote in message news:kGe2d.33750$KU5.29372@edtnps89...
You're kidding, right?

The 807 was the most-used amplifier tube in history. It still beats the
6146 in popularity, given the time it was used. From audiophile tube amps,
to RF modulators to RF linears and class-C self excited power oscillators,
the 807 was/is there :-)

RF schematics are all over. Check Google, check the ARRL Handbook, CB
websites and pirate radio websites.

Russia and China still make it. Russian ones are the best and called
G-807.

If you want to play with an 807 at audio, for all practical purposes, it's
a 6L6GC ;-)

No, I am not kidding - if I wanted to use them at audio thats simple
enough - havent been able to find many references to them via Google -
perhaps you could post a few? - and most designs of the 50's in push
pull had bugger all output filtering so were not up to todays more
rigorous standards for spectral purity. As well, were reltively low
powered. My dilemma is with simple aerials I can hear stations 5 by 9
but they cant here me on a band where everyone is running 400w plus
with gain directional antennas. Sure, could buy a Yaesu FL2100, but
the price of tubes is outrageous (by my standards, anyway) and the
amps using 4CX series are even more so. The Ameritron stuff using
811's look better, but dont have any of them in the junk box - this IS
a homebrew website, after all.

Have built in the past with 807's, from fading memeory 2 tubes in
push pull would give about 60 watts - since most modern HF rigs give
100 watts, there is little point in doing a design like that except
for nostalgia.

I should clarify my question - they are available dirt cheap,
(sometimes free) power supply requirements are relatively modest (at
750v plate) and they are certainly more rugged and forgiving than
modern ceramic tubes.

And I know the evolution of the things, thats basic radio history.

73 de VK3BFA Andrew

Ken,

I recall one amp used a voltage quadrupler to get 600 volts from
the 120v ac line and had 10 tubes with the heaters wired in series.
One tube was a driver, and 9 were grounded grid finals.
(A bit of a shock hazzard perhaps.)

I've seen something similar here in the UK 20+ years back and remember
the amateur who built the thing. I think he was playing around the Kw
level and with no transformers in sight.

We do have a head start on you fellas with 240v @ 50Hz :-)

A 'bit' of a shock hazard is kind of an understatement don't you think.
--
Philip de Cadenet G4ZOW
Transmitters 'R' Us
http://www.transmittersrus.com