"Stev eH"
StevehkhhSDJvhvbjjxbvvbhnvbhzjdnxzvzhzdshbvnjzvnb vnvjbvbcjbvvvvnmxvzjhjzsdgfgsfghgjsghgsljhglhdjfgh fufgfhzysgfhczgugfvzlvufzvllgfzlyfyvlgbylvdfghvbly
wrote in message ...
My first amp had 3 PL519s with a lethal power supply using a voltage
tripp{l}er direct off the 240V mains, heaters were direct off mains via a
1n5406 diode. It's still up in the parents loft somewhere, must dig it
out over the holidays and give it a try....

Steve H


Do you realize that the RMS value of half-wave rectified AC is not one half
of the applied RMS voltage but rather 0.707 of the applied RMS voltage. So
your three 40 volt filament PL519s actually saw about 56 volts RMS across
each filament. I'll bet you wondered why the filaments were so bright.

To properly measure this voltage, you need a true RMS voltmeter. Most
inepensive AC voltmeters actually measure the peak voltage and display the
result on a scale calibrated for a sine wave input. RMS (root mean square)
is the equivalent DC voltage that would produce the same HEATING in a
resistance as the applied waveform.

Most hams are quite confused by this. Looking over some websites
explaining this, one of the better ones is a Google Book Search of
"Electric Machinery Fundamentals" by Stephen J. Chapman who presents the
mathematics in detail starting on page 163:
http://books.google.com/books?id=ltg...m=10&ct=result

As an interesting side note, the Philips datasheet on the PL519 is the
first I have seen that explicitly discusses Barkhausen interference and how
to suppress it.

73, Dr. Barry L. Ornitz WA4VZQ

"NoSPAM" wrote in
:

snips
"Electric Machinery Fundamentals" by Stephen J. Chapman who presents
the mathematics in detail starting on page 163:
snips



Howdy,

Coincidence! That book is on my kitchen table at the moment.
It's ok, but this is probably more suited to the purpose;
http://www.tpub.com/neets/book7/27a.htm


73,Grumpy

On Thu, 04 Dec 2008 21:24:37 +0000, Stev eH wrote:

Registered User wrote:
On Thu, 04 Dec 2008 17:56:27 +0000, Stev eH
StevehkhhSDJvhvbjjxbvvbhnvbhzjdnxzvzhzdshbvnjzvnb vnvjbvbcjbvvvvnmxvzjhjzsdgfgsfghgjsghgsljhglhdjfgh fufgfhzysgfhczgugfvzlvufzvllgfzlyfyvlgbylvdfghvbly
wrote:

The sockets for the 807 are rare

The 807 uses a readily available 5 contact socket. The 1625 (12V
equivalent) uses a 7 contact socket which can be difficult to locate.

73 de n4jvp
I'm in the UK and haven't been able to find any at the local hamfests,
where can I get them from? Octal sockets are readily available over here.

Steve H

I have some. How many you need?

Cheers,

Gregg

On Dec 4, 1:20*pm, Registered User wrote:
On Thu, 04 Dec 2008 17:56:27 +0000, Stev eH
StevehkhhSDJvhvbjjxbvvbhnvbhzjdnxzvzhzdshbvnjzvnb vnvjbvbcjbvvvvnmxvzjhjzsd*gfgsfghgjsghgsljhglhdjfg hfufgfhzysgfhczgugfvzlvufzvllgfzlyfyvlgbylvdfghvbl
wrote:

The sockets for the 807 are rare

The 807 uses a readily available 5 contact socket. The 1625 (12V
equivalent) uses a 7 contact socket which can be difficult to locate.

Chinese Ceramic 5- and 7-pin sockets for 807's and 1625's are readily
available. e.g. P-ST5-216 and P-ST7-311 from Antique Electronic
Supply, or the same thing from ESRC on Ebay, items 130273824548 and
130273500741, or similar thigns from at least a dozen other web
suppliers. (Antique Electronic Supply and ESRC I've been doing
business with for many years). Vintage ceramic sockets from the 40's
and 50's made by EF Johnson etc. turn up at hamfests pretty regularly
too.

Tim N3QE

On Thu, 04 Dec 2008 06:23:48 -0800, JIMMIE wrote:

After years of avoiding morse code I am finally getting into it. the
ideal of operating a very simple transmitter appeals to my junkbox/
trashcan construction mentality.
I am looking for a substitue for a 6L6 that has the plate brought out
the top. I was trying to build a little Glowbug transmitter but was
having all kinds of problems neutralizing the the thing. I think I would
have better luck if I can separate the grid and plate circuits from each
other. I am considering an 807 as a replacement Suggestions would be
appreciated.

Jimmie

Dunno if it's been mentioned yet -- 2E26. The 807 is _not_ a 6L6 in a
different envelope -- it's quit arguably the 6L6's big brother, but it's
got different ratings; it could probably be shoe-horned into a circuit
designed for the 6L6, but you'd be missing out on about 6dB of final
output power.

Antique Electronics Supply has 2E26's for $6.00 each, so it's not a bad
buy -- and the 2E26 goes into an octal socket.

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html

On Thu, 04 Dec 2008 06:23:48 -0800, JIMMIE wrote:

After years of avoiding morse code I am finally getting into it. the
ideal of operating a very simple transmitter appeals to my junkbox/
trashcan construction mentality.
I am looking for a substitue for a 6L6 that has the plate brought out
the top. I was trying to build a little Glowbug transmitter but was
having all kinds of problems neutralizing the the thing. I think I would
have better luck if I can separate the grid and plate circuits from each
other. I am considering an 807 as a replacement Suggestions would be
appreciated.

Jimmie

Have you considered a 6L6 with careful shielding at the socket? IIRC the
pins that neighbor the plate pin would be at RF potential; you could put
a big, flat, high-value ceramic right between those socket pins to shield
the grid, and possible even extend the shield out if you were willing to
hand-make a cap from copper strip and Kapton tape.

It's kinda heroic measures to take on a tube that's more expensive now
than it's "high-tech" RF brethren, but if you just gotta have that metal-
tube look it may do the trick.

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html

On Dec 5, 11:28*am, Tim Wescott wrote:
On Thu, 04 Dec 2008 06:23:48 -0800, JIMMIE wrote:
After years of avoiding morse code I am finally getting into it. the
ideal of operating a very simple transmitter appeals to my junkbox/
trashcan construction mentality.
I am looking for a substitue for a 6L6 that has the plate brought out
the top. I was trying to build a little Glowbug transmitter but was
having all kinds of problems neutralizing the the thing. I think I would
have better luck if I can separate the grid and plate circuits from each
other. I am considering an 807 as a replacement Suggestions would be
appreciated.

Jimmie

Have you considered a 6L6 with careful shielding at the socket? *IIRC the
pins that neighbor the plate pin would be at RF potential; you could put
a big, flat, high-value ceramic right between those socket pins to shield
the grid, and possible even extend the shield out if you were willing to
hand-make a cap from copper strip and Kapton tape.

It's kinda heroic measures to take on a tube that's more expensive now
than it's "high-tech" RF brethren, but if you just gotta have that metal-
tube look it may do the trick.

--
Tim Wescott
Control systems and communications consultinghttp://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes,http://www.wescottdesign.com/actfes/actfes.html

I have a NOS 6DQ6 I can use in place of the 6L6s. I think they will
work. the biggest problem will be relocating the plate circuit. I will
have to add a front panel to my "fool killer" to hold the tuning
caps.


Jimmie

geek wrote:
On Thu, 04 Dec 2008 21:24:37 +0000, Stev eH wrote:

Registered User wrote:
On Thu, 04 Dec 2008 17:56:27 +0000, Stev eH
StevehkhhSDJvhvbjjxbvvbhnvbhzjdnxzvzhzdshbvnjzvnb vnvjbvbcjbvvvvnmxvzjhjzsdgfgsfghgjsghgsljhglhdjfgh fufgfhzysgfhczgugfvzlvufzvllgfzlyfyvlgbylvdfghvbly
wrote:

The sockets for the 807 are rare
The 807 uses a readily available 5 contact socket. The 1625 (12V
equivalent) uses a 7 contact socket which can be difficult to locate.

73 de n4jvp
I'm in the UK and haven't been able to find any at the local hamfests,
where can I get them from? Octal sockets are readily available over here.

Steve H

I have some. How many you need?

Cheers,

Gregg

I could do with a pair, I have several 807 in the junk box and the look
far better to me than the "Modern" style of valve. The email address is
valid BTW.

Steve H

On Dec 5, 12:27*pm, Stev eH
I could do with a pair, I have several 807 in the junk box and the look
far better to me than the "Modern" style of valve.

Even modern Chinese-made 807's have the ST glass shape.

The one that is not sexy is the 807W.

My favorite book of tube pr0n is "RCA Air-Cooled Transmitting Tubes",
TT3. Great big full-page engravings of the best tubes. Worth all 25
cents.

Tim.

On Fri, 05 Dec 2008 17:27:27 +0000, Stev eH wrote:

geek wrote:
On Thu, 04 Dec 2008 21:24:37 +0000, Stev eH wrote:

Registered User wrote:
On Thu, 04 Dec 2008 17:56:27 +0000, Stev eH
StevehkhhSDJvhvbjjxbvvbhnvbhzjdnxzvzhzdshbvnjzvnb vnvjbvbcjbvvvvnmxvzjhjzsdgfgsfghgjsghgsljhglhdjfgh fufgfhzysgfhczgugfvzlvufzvllgfzlyfyvlgbylvdfghvbly
wrote:

The sockets for the 807 are rare
The 807 uses a readily available 5 contact socket. The 1625 (12V
equivalent) uses a 7 contact socket which can be difficult to locate.

73 de n4jvp
I'm in the UK and haven't been able to find any at the local hamfests,
where can I get them from? Octal sockets are readily available over here.

Steve H

I have some. How many you need?

Cheers,

Gregg

I could do with a pair, I have several 807 in the junk box and the look
far better to me than the "Modern" style of valve. The email address is
valid BTW.

Steve H

Hi Steve,

Sent you an email :-)

Mine is geek at scorpiorising dot ca if you don't get it.

Cheers,

Gregg