the 6.3 VAC is ok ,no need to go into the fuss for dc.
dont take my word for it, after making the nice rig put some diodes on the
ac line and you will not see anythig special..
73's




--
http://www.qsl.net/sv1hao


"Biz WDØHCO" wrote in message
...
After 31 years and a bunch of parts in the garage, I am finally building
my
dream CW receiver from scratch.

Just wondering if I converted the 6.3 VAC filament voltage to a DC voltage
if doing so would be worth the effort to reduce hum.

Opinions ?

Also I would like to cut a round 4" diameter hole in the 1/8" aluminum
front
panel for the speaker grill. Is there a way to do this without a Greenlee
Pneumatic punch? I have a jig saw which I can cut square holes but round
holes are another matter. Is there a better way? I can drill round holes
up
to 7/8" with a unibit but I think 7/8" is as big as they get.

Thanks

Biz - WDØHCO

Swells8044 wrote:

Go to Home Depot get a 4 in.hole saw.They are made for wood but will cut a few
holes in al.
Steve


And use oil or something to keep the Al. from sticking to the teeth.

Bill K7NOM

W7TI writes:

On Tue, 28 Oct 2003 18:38:39 -0600, Biz WDØHCO wrote:

Just wondering if I converted the 6.3 VAC filament voltage to a DC
voltage if doing so would be worth the effort to reduce hum.

Opinions ?

AC will work fine, but here's the key: Don't ground either side of
the 6.3 volt line. Many hum problems are caused by ground loops
where one side of the filament voltage is run through the chassis.
Manufacturers used to do this to save a few pennies by having only
one filament wire. In a mass production situation this can be made
to work, but for one-off design it's easier and better to just keep
the filament voltage isolated from the chassis or anything else.
Use a twisted pair and run it from socket to socket.

If I did this I would put a 0.01 uF capacitor to ground at each
filament pin, to keep RF from propegating through the wires. I would
also put a resistor to ground somewhere in the string to bleed off any
stray leakage current (maybe 1000 ohms or so), otherwise you might get
voltage buildup that could cause problems.

What about an inadvertent short between the cathode and filament?

Allen

the 6.3 VAC is ok ,no need to go into the fuss for dc.
dont take my word for it, after making the nice rig put some diodes on the
ac line and you will not see anythig special..
73's




--
http://www.qsl.net/sv1hao


"Biz WDØHCO" wrote in message
...
After 31 years and a bunch of parts in the garage, I am finally building
my
dream CW receiver from scratch.

Just wondering if I converted the 6.3 VAC filament voltage to a DC voltage
if doing so would be worth the effort to reduce hum.

Opinions ?

Also I would like to cut a round 4" diameter hole in the 1/8" aluminum
front
panel for the speaker grill. Is there a way to do this without a Greenlee
Pneumatic punch? I have a jig saw which I can cut square holes but round
holes are another matter. Is there a better way? I can drill round holes
up
to 7/8" with a unibit but I think 7/8" is as big as they get.

Thanks

Biz - WDØHCO

Also I would like to cut a round 4" diameter hole in the 1/8" aluminum
front
panel for the speaker grill. Is there a way to do this without a Greenlee
Pneumatic punch? I have a jig saw which I can cut square holes but round
holes are another matter. Is there a better way? I can drill round holes
up
to 7/8" with a unibit but I think 7/8" is as big as they get.
=========================
Suggest you drill multiple holes ( as close to each other as possible) with
a 1/8 inch drill all around a circle with a diameter of
3 13/16 inch .
Then knock out the circular bit of aluminium and file with a half round file
to 4 inch diameter.
It is a bit of a job but will give a good result.
Alternatively you can cut out the 4 inch circular bit with a jig saw ,using
methylated spirit as 'lubricant'.
Finish with a fine file or emery paper.

Frank GM0CSZ / KN6WH

Also I would like to cut a round 4" diameter hole in the 1/8" aluminum
front
panel for the speaker grill. Is there a way to do this without a Greenlee
Pneumatic punch? I have a jig saw which I can cut square holes but round
holes are another matter. Is there a better way? I can drill round holes
up
to 7/8" with a unibit but I think 7/8" is as big as they get.
=========================
Suggest you drill multiple holes ( as close to each other as possible) with
a 1/8 inch drill all around a circle with a diameter of
3 13/16 inch .
Then knock out the circular bit of aluminium and file with a half round file
to 4 inch diameter.
It is a bit of a job but will give a good result.
Alternatively you can cut out the 4 inch circular bit with a jig saw ,using
methylated spirit as 'lubricant'.
Finish with a fine file or emery paper.

Frank GM0CSZ / KN6WH

HAVE YOU EVER HEARD OF
DRILLING LOTS OF SMALLER HOLES AROUND
THE DIAMATER , UNTILL THE CENTER DROPS OUT
AND THEN FILLING THE EDGES SMOOTH


THE GOOD OLD FLE WORKS WONDERS ...HMMMM


DE PAUL

HAVE YOU EVER HEARD OF
DRILLING LOTS OF SMALLER HOLES AROUND
THE DIAMATER , UNTILL THE CENTER DROPS OUT
AND THEN FILLING THE EDGES SMOOTH


THE GOOD OLD FLE WORKS WONDERS ...HMMMM


DE PAUL

In article , W7TI
writes:

On Sat, 8 Nov 2003 13:27:07 -0000, "uk-hamman"
wrote:

HAVE YOU EVER HEARD OF
DRILLING LOTS OF SMALLER HOLES AROUND
THE DIAMATER , UNTILL THE CENTER DROPS OUT
AND THEN FILLING THE EDGES SMOOTH

THE GOOD OLD FLE WORKS WONDERS ...HMMMM
_________________________________________________ ________

This is how our Neanderthal ancestors did it, and if it was good enough
for them....
--
Bill, W7TI

Practically speaking (as one neanderthal to another...):

That method does work if there's no drill press available. But, be
sure to buy an extra drill bit for the size desired going around the
rim. Had to do that with a 4 1/4" diameter speaker hole in an 1/8"
aluminum rack panel (alloy tougher than 2024 but not as stiff as
6061). That included light oil lubrication. The "center" didn't
"drop right out" but centerpunching the many holes right allowed
using old wire cutters to snip the narrow left-overs between holes.

A Hand File to complete?!?!? Good grief, no. A Dremel Moto-Tool
with several "mill type" cutter bits is much preferred to smooth out
the rough edges. Note: Home Depot, Lowe's, Do-It-Centers, OSH,
all carry extra bits for Dremel Moto-Tools, many which aren't
included in the Dremel kits. Use a biggie mill cutter to hog out the
worst, go to a small bit to smooth those edges. One of several
grind wheels can be used to finish it off. Takes a steady hand
(usually both hands if panel is in a vise).

Absolutely needed: A scribe marked circle on the panel as a guide!
Maybe two concentric circles, the inner one slightly smaller than
desired as a "target." If one gets sloppy, it's possible to cut farther
out than the inner, smaller "target" circle. To get the scribed circle,
use a grade-school compass in REVERSE, the "pencil" part in a
small drill hole at center, the "center" part (pointy end) doing the
scribing.

Dremel also makes a dandy mini-drill-press stand for the Moto-Tool
which is just lovely for through-hole PCB drilling. I use one for that
plus the AC line voltage adjusted with a Powerstat (Superior Electric)
variable autotransformer to control the "drill press" speed. BTW,
liquid hand soap, slightly diluted, works out as a PCB drilling
lubricant and washes out with hot water...and can be used with a
rough-surface sponge to buff out surface oxidation on the copper
foil or removing tiny burrs in the drill holes.

Len Anderson
retired (from regular hours) electronic engineer person

In article , W7TI
writes:

On Sat, 8 Nov 2003 13:27:07 -0000, "uk-hamman"
wrote:

HAVE YOU EVER HEARD OF
DRILLING LOTS OF SMALLER HOLES AROUND
THE DIAMATER , UNTILL THE CENTER DROPS OUT
AND THEN FILLING THE EDGES SMOOTH

THE GOOD OLD FLE WORKS WONDERS ...HMMMM
_________________________________________________ ________

This is how our Neanderthal ancestors did it, and if it was good enough
for them....
--
Bill, W7TI

Practically speaking (as one neanderthal to another...):

That method does work if there's no drill press available. But, be
sure to buy an extra drill bit for the size desired going around the
rim. Had to do that with a 4 1/4" diameter speaker hole in an 1/8"
aluminum rack panel (alloy tougher than 2024 but not as stiff as
6061). That included light oil lubrication. The "center" didn't
"drop right out" but centerpunching the many holes right allowed
using old wire cutters to snip the narrow left-overs between holes.

A Hand File to complete?!?!? Good grief, no. A Dremel Moto-Tool
with several "mill type" cutter bits is much preferred to smooth out
the rough edges. Note: Home Depot, Lowe's, Do-It-Centers, OSH,
all carry extra bits for Dremel Moto-Tools, many which aren't
included in the Dremel kits. Use a biggie mill cutter to hog out the
worst, go to a small bit to smooth those edges. One of several
grind wheels can be used to finish it off. Takes a steady hand
(usually both hands if panel is in a vise).

Absolutely needed: A scribe marked circle on the panel as a guide!
Maybe two concentric circles, the inner one slightly smaller than
desired as a "target." If one gets sloppy, it's possible to cut farther
out than the inner, smaller "target" circle. To get the scribed circle,
use a grade-school compass in REVERSE, the "pencil" part in a
small drill hole at center, the "center" part (pointy end) doing the
scribing.

Dremel also makes a dandy mini-drill-press stand for the Moto-Tool
which is just lovely for through-hole PCB drilling. I use one for that
plus the AC line voltage adjusted with a Powerstat (Superior Electric)
variable autotransformer to control the "drill press" speed. BTW,
liquid hand soap, slightly diluted, works out as a PCB drilling
lubricant and washes out with hot water...and can be used with a
rough-surface sponge to buff out surface oxidation on the copper
foil or removing tiny burrs in the drill holes.

Len Anderson
retired (from regular hours) electronic engineer person