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--- wrote
"To attenuate RF interference, has anybody thought about
using grounded aluminum or copper foil inside the unit, or
maybe wrapping the tank with copper tape?"
John:
I think Dave Wronski wrote about this topic once here at
SG101...
maybe he was discussing "in the pickup cavity" guitar
shielding, but that's almost the same concept as "in the
tank" shielding.
-dp
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John,
Your idea has merit. I've never seen it done, but
there's an easy test to make to see if the pan is
indeed the culprit.
Simply remove the pan, leave it connected to the
circuitry, and fire everything up. Make the problem
appear, and then see if you can make it disappear
by moving the pan around. If you can, then you
need to sheild the pan. If not, then the pan
isn't the problem.
If your test says "shield it!", then make sure
that you don't hook up several pieces of wire
from each individual shield piece to one point.
Instead, run a wire from one piece to the next,
and from the last one over to the ground lug
on one of the jacks. DON'T hook up a wire from
the first piece to the ground lug, that creates
a ground loop, which means a hum will be heard.
One more thing..... If you wrap the tank with
a tape, make sure you have enough clearance so
that the springs can't hit against the tape.
If any of the tape's adhesive were to transfer
to the springs, I don't think it would be a
pretty picture. <g>
unlunf
> --- john.blair@s... wrote
>
> "To attenuate RF interference, has anybody thought about
> using grounded aluminum or copper foil inside the unit, or
> maybe wrapping the tank with copper tape?"
>
I have been wondering if the pan itself could have been the problem with RFI,
but I don't think so because it operates at a much higher level than the input
or driver stages. It is post 6v6 (6k6). But something on that pc board is
acting as an antenna. The old units with point to point just don't have that
problem (I have two of them). I have only had it pick up stations in several
isolated cases. But it was screaming some awful country station at the Beach
Boys show. I even bought a "Holy Grail" as a "Hail Mary" backup should it
ever be needed......The Holy Grail is no real substitue. If we keep this up,
we may get to the bottom of this........thanks for the inputs guys.......eddie k
the culprit.
Simply remove the pan, leave it connected to the
circuitry, and fire everything up. Make the problem
appear, and then see if you can make it disappear
by moving the pan around. If you can, then you
need to sheild the pan. If not, then the pan
isn't the problem.
If your test says "shield it!", then make sure
that you don't hook up several pieces of wire
from each individual shield piece to one point.
Instead, run a wire from one piece to the next,
and from the last one over to the ground lug
on one of the jacks. DON'T hook up a wire from
the first piece to the ground lug, that creates
a ground loop, which means a hum will be heard.
One more thing..... If you wrap the tank with
a tape, make sure you have enough clearance so
that the springs can't hit against the tape.
If any of the tape's adhesive were to transfer
to the springs, I don't think it would be a
pretty picture. <g>
unlunf
> --- john.blair@s... wrote
>
> "To attenuate RF interference, has anybody thought about
> using grounded aluminum or copper foil inside the unit, or
> maybe wrapping the tank with copper tape?"
>
.
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[Non-text portions of this message have been removed]
I don't have RFI problems with my reverb, heck, I don't even have a
stand alone reverb (I plan to build one soon), so I can't try this, but
if you are having problems, it might be worth while to try using
ferrite beads in a few judicious places (input/output jacks, power
chord, reverb cables).
Info on ferrite beads here:
engineers.com/RFI_Kit/rfi_kit.html and
I am posting this on behalf of Dave Wronski. He tried to post it
himself, but somehow somewhere someone's reverbtank's Rob seems to be
screwing the internet now, hence this post took the via netherlands
route...
"Remember that the transducers in the spring pan are single coil
pickups. If you have a buzz problem, try slowly turning the reverb
unit until the buzz is canceled out. Do this like you do with your
guitar when it buzzes. There will be a direction you point the neck
where the buzz stops.
I shield Fender tanks two ways. With my '65 I took aluminum foil and
folded it about three layers thick, and put it over the grill cloth,
under the logo and front board mounting screws., Use a wire attached
under one of the front board mounting screws to the chassis ground,
or input jack.
On my '62, putting the foil on the outside didn't work as well. I had
to put the foil on the inside surface of the front board, and wrapped
it in saran clear plastic wrap to isolate it. Don't forget to ground
the foil if you try this.
If you have an old Fender unit, make a foil shield for the back
panel. It will be grounded when you screw the back board on.
This really can make a nice difference in the noise level. Another
tip for shaky stages... Put the reverb unit on it's end, instead of
on the long flat side.
--- dave
--dave_wronski"
Surf guitarists are only a couple of problems away that plauge us that
we start to wear aluminum foils caps or we just start wrapping
everything foil.
All of my Fender reverb units (two so far, plus a Weber kit and the reverb on my
Twin) have
been susceptible to radio interference to some degree. I kept one reverb unit in
a box
fully-lined with aluminum foil, and still had problems! Often, the issue was -
now, sit
down - the cable running from the foot pedal. While eliminating this didn't
always solve
the problem, it did minimize the problem on both my amp and one of my boxes.
Gavin
--- In , John McCorvey <eddiekatcher@y...> wrote:
>
> I have been wondering if the pan itself could have been the problem with RFI,
but I
don't think so because it operates at a much higher level than the input or
driver stages. It
is post 6v6 (6k6). But something on that pc board is acting as an antenna. The
old units
with point to point just don't have that problem (I have two of them). I have
only had it
pick up stations in several isolated cases. But it was screaming some awful
country station
at the Beach Boys show. I even bought a "Holy Grail" as a "Hail Mary" backup
should it
ever be needed......The Holy Grail is no real substitue. If we keep this up,
we may get to
the bottom of this........thanks for the inputs guys.......eddie k
>
>
>
> the culprit.
>
> Simply remove the pan, leave it connected to the
> circuitry, and fire everything up. Make the problem
> appear, and then see if you can make it disappear
> by moving the pan around. If you can, then you
> need to sheild the pan. If not, then the pan
> isn't the problem.
>
> If your test says "shield it!", then make sure
> that you don't hook up several pieces of wire
> from each individual shield piece to one point.
> Instead, run a wire from one piece to the next,
> and from the last one over to the ground lug
> on one of the jacks. DON'T hook up a wire from
> the first piece to the ground lug, that creates
> a ground loop, which means a hum will be heard.
>
> One more thing..... If you wrap the tank with
> a tape, make sure you have enough clearance so
> that the springs can't hit against the tape.
> If any of the tape's adhesive were to transfer
> to the springs, I don't think it would be a
> pretty picture. <g>
>
>
> unlunf
>
>
> > --- john.blair@s... wrote
> >
> > "To attenuate RF interference, has anybody thought about
> > using grounded aluminum or copper foil inside the unit, or
> > maybe wrapping the tank with copper tape?"
> >
>
>
>
>
>
>
>
> .
> Visit for archived messages,
bookmarks,
files, polls, etc.
>
>
>
>
> SPONSORED LINKS
> Guitar music theory Stringed instruments Guitar music book
Guitar sheet
music Guitar music sheets Guitar technique
>
> ---------------------------------
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>
>
> Visit your group "SurfGuitar101" on the web.
>
> To unsubscribe from this group, send an email to:
>
>
> Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
>
>
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>
>
>
>
>
>
> ---------------------------------
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> [Non-text portions of this message have been removed]
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