8mm Forum: Braun visacustic earthing

8mm Forum

my profile | my password | search | faq | register | forum home

next oldest topic

next newest topic

»	8mm Forum » 8mm Forum » Braun visacustic earthing

UBBFriend: Email this page to someone!

Author

Topic: Braun visacustic earthing

Jose Artiles
Master Film Handler

Posts: 357
From: Spain
Registered: Oct 2005

posted September 06, 2017 01:46 PM

Email Jose Artiles

Send New Private Message

Edit/Delete Post

I have a Braun visacustic 1000 that have a plug outside, on the projector chassis for earthing,,can someone tell me how i can proceed to do the earthing please?
Thanks in advance friends!

--------------------
As Steven Spielberg says....
Nothing beats old school projection. Digital is just an imitation.

| IP: Logged

Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

posted September 06, 2017 02:40 PM

Email Steve Klare

Send New Private Message

Edit/Delete Post

It looks like this is an interesting one:

Visacustic Grounding: towards the end of the first post

I guess they were trying to avoid ground loops by offering the user the ability to connect ground as they saw fit

I don't like the idea of operating this kind of equipment ungrounded (been shocked a few times...professional liability!).

If it were me I'd ground that banana jack and bust the ground loops some other way. You'd probably need to make a special cable.

It could be worse: my Eumig 800 series has the three prong power inlet but came with a two prong line cord. I guess the idea there was just float the machine and ground it thorough other connected equipment...or the customer!

(I fixed this.)

--------------------
All I ask is a wide screen and a projector to light her by...

| IP: Logged

Renzo Dal Bo
Film Handler

Posts: 70
From: Mogliano Veneto, Italy
Registered: Dec 2016

posted September 07, 2017 03:47 AM

Email Renzo Dal Bo

Send New Private Message

Edit/Delete Post

Hi
from the Visacustic user manual:

| IP: Logged

Maurice Leakey
Film God

Posts: 5895
From: Bristol. United Kingdom
Registered: Oct 2007

posted September 07, 2017 06:27 AM

Email Maurice Leakey

Send New Private Message

Edit/Delete Post

Well.
I'm still alive after using my Braun Visacustic 1000 Stereo after nine years, and only connecting to the 2-pin plug with a standard "kettle" lead.
And, no earthing. [Smile]

[Smile]

--------------------
Maurice

| IP: Logged

Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

posted September 07, 2017 06:31 AM

Edit/Delete Post

I think the standard mains IEC plug, lead and socket provide more than adequate earthing for the projector itself.
I would be most surprised if Braun themselves did not use the earth terminal provision on the IEC socket to chassis for the machine itself.

It would appear this is just an additional measure to reduce hum possibly only experienced when the projector is connected to other audio equipment just to reduce any unnecessary hum through the loudspeaker(s).

What I find a little odd about this particular machine, is it is a full true Stereo model yet was only ever supplied originally with one speaker. [Confused]

[Confused]

--------------------
"C'mon Baggy..Get with the beat"

| IP: Logged

Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

posted September 07, 2017 06:41 AM

Email Steve Klare

Send New Private Message

Edit/Delete Post

To me it looks like there is no ground through the mains plug, as it says in the post I referenced.

Is it safe to operate the machine ungrounded? Probably. It would be safer to ground it, though.

There's a lot of older machines than this one with metal chassis without any grounding at all. Just like if you take a seat at the wheel of many classic cars there are no seatbelts (never mind airbags).

Your chances of coming out OK are still good in either case, just a lot better with grounded line cords or seatbelts and airbags.

Does this machine have some kind of safety agency mark of it? It just may be double insulated, which would make operating it without the third prong OK. If it has this it's the only projector I ever heard of that does. (This is something usually associated with corded power tools.)

--------------------
All I ask is a wide screen and a projector to light her by...

| IP: Logged

Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

posted September 07, 2017 06:45 AM

Edit/Delete Post

This is very modern machine by Super 8mm standards so despite it's all plastic exterior (double insulated), I have never seen any other similar models without the earth terminal used from the IEC mains inlet socket.

Stuart Reid also has one of these machines so I will check with him how the actual mains socket appears and is connected on these models.

--------------------
"C'mon Baggy..Get with the beat"

| IP: Logged

Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

posted September 07, 2017 06:48 AM

Email Steve Klare

Send New Private Message

Edit/Delete Post

A plastic case helps. Many double insulated appliances have this.

It also looks like the supplied inlet is 3 prong, but the original supplied cord is two (like my Eumig).

If the third inlet prong is grounded (and it should be), you could ground the machine by subbing a standard IEC power cord. This is what I did with my Eumig machine.

--------------------
All I ask is a wide screen and a projector to light her by...

| IP: Logged

Maurice Leakey
Film God

Posts: 5895
From: Bristol. United Kingdom
Registered: Oct 2007

posted September 07, 2017 06:58 AM

Email Maurice Leakey

Send New Private Message

Edit/Delete Post

The projector only has two pins on its mains input plug. I thought I had made this quite clear.
It does, of course. accept the 3-pin socket on the end of the mains lead, but there is no pin for the earth connection.

--------------------
Maurice

| IP: Logged

Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

posted September 07, 2017 07:03 AM

Edit/Delete Post

That is really unusual then Maurice and thank you for clarification with this.

I cannot for the life of me understand the mindset of the design regarding this appliance then, especially given the era these were made. [Wink]

[Wink]

I cannot think of one similar machine that utilizes this arrangement or any advantages from doing so. [Confused]

[Confused]

Maybe it has an all rubber transformer including it's windings! [Big Grin]

[Big Grin]

[Big Grin]

If it were mine, I would place a standard connected socket to it and earth it back to the chassis and transformer just to feel safe using it as these things age.
You never want to risk giving any electrical apparatus the easiest path to earth through the water in your body!

--------------------
"C'mon Baggy..Get with the beat"

| IP: Logged

Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

posted September 07, 2017 08:04 AM

Email Steve Klare

Send New Private Message

Edit/Delete Post

Not just water, salt water!

Most of us don't have that kind of musical talent, but at least electrically we are all good conductors!

I can't help but think a reputable company like this went the double-insulated route, and that would include how the transformer is constructed too.

Grounding and audio is a major pain in the butt. This is a creative way to deal with it, to say the least.

It's interesting: I visited my own Eumig 800 series this morning on the way to work, and saw there is no Underwriters' Laboratory mark on the label. I'm betting with a metal case and a two prong cord, they couldn't get the cert.

--------------------
All I ask is a wide screen and a projector to light her by...

| IP: Logged

Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

posted September 07, 2017 08:29 AM

Edit/Delete Post

Yes i'm sure you are quite correct Steve, an attempt to combat the dreaded ground hum issue quite prevalent on smaller bodied machines where the transformer cannot be fitted far enough away really, by attempting this double insulated method of approach again.
i cannot say i am a fan especially as our machines reach old age and if it were my own i would be exchanging that two pin IEC socket for a standard three pin arrangement in a heartbeat!

I'd leave the existing one as is (earth socket) as it is as it is probably routed more directly to the amplifier section and just route some earth flex from the IEC socket terminal to two mounting points on the internal metal chasis at suitable points, one being the transformer and perhaps the motor body also depending on the voltage supplied to it.

--------------------
"C'mon Baggy..Get with the beat"

| IP: Logged

Stuart Reid
Jedi Master Film Handler

Posts: 720
From: Worthing, West Sussex, UK
Registered: Feb 2009

posted September 07, 2017 08:41 AM

Send New Private Message

Edit/Delete Post

Bang on Andrew, excellent belt and braces approach to stop you bracing for a belt! [Big Grin]

[Big Grin]

| IP: Logged

Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

posted September 07, 2017 08:44 AM

Email Steve Klare

Send New Private Message

Edit/Delete Post

I'd almost have to go three prong: I'm a member of the electrical safety committee at work! Being electrocuted would be not only deadly but embarrassing!

Actually the ground loop issue and the internal hum issue are different. The ground loops we usually fight are caused mostly outside the audio components and mostly from voltages induced on the ground conductor by the currents in the hot and neutral wires inside the building wiring. Internal hum is stuff like supply ripple and pickup by the sound heads (you can have a local ground loop inside the projector too).

This is why hum problems can be perplexing to fix: You can have them both, fix either one and still have hum from the other. It's tempting to give up even though you are actually halfway there.

--------------------
All I ask is a wide screen and a projector to light her by...

| IP: Logged

Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

posted September 07, 2017 09:47 AM

Edit/Delete Post

It may very well be trade off by permanently earthing this projector but so long as hum during ordinary playback isn't excessive after doing so, I personally would rather live with that as opposed to handling something that could potentially leave me not watching any films at all in the future! [Wink]

[Wink]

This arrangement could be trialed first without disrupting any of the current set up regarding the IEC socket.

--------------------
"C'mon Baggy..Get with the beat"

| IP: Logged

Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

posted September 07, 2017 10:37 AM

Email Steve Klare

Send New Private Message

Edit/Delete Post

True,

The machine could be grounded to the outlet through the banana jack first.

My Amp has a similar arrangement: two prong mains lead and a ground lug on the chassis. I don't use it though. Ground there is through RCA cables to my TV, then through coax to my cable TV provider. (Grounding gets ugly sometimes...) This is why I need ground loop isolation to my cinema setup: it's just plugged into house current and grounded to the water pipes.

-I actually measured 3 volts between these two "grounds" once!

--------------------
All I ask is a wide screen and a projector to light her by...

| IP: Logged

Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

posted September 07, 2017 04:08 PM

Edit/Delete Post

Not bad Steve for something where there should be no real potential difference when you measure across them all! [Big Grin]

[Big Grin]

--------------------
"C'mon Baggy..Get with the beat"

| IP: Logged

Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

posted September 07, 2017 05:17 PM

Email Steve Klare

Send New Private Message

Edit/Delete Post

Should be for certain. Unfortunately it's closely bundled with other wires and their magnetic fields give you kind of an unwanted transformer with the ground wire being the secondary. (I think the major culprit my case is the cable TV system.)

For what grounding is really meant to do, this is no big deal: human contact becomes dangerous above 60 volts. What's a few volts among friends by this standard?

-but then we start mixing line level audio into this mess: a great big 1V RMS signal.

No wonder things hum!

--------------------
All I ask is a wide screen and a projector to light her by...

| IP: Logged

All times are Central

Move Topic

Delete Topic

next oldest topic

next newest topic

Printer-friendly view of this topic

Visit www.film-tech.com for free equipment manual downloads. Copyright 2003-2019 Film-Tech Cinema Systems LLC

UBB.classic^TM 6.3.1.2