Help! camera flash clicks in audio system

[bradp015]

Just some more info:

I have a PC Back-UPS Pro® 1000 on some of the recording rig, (enough time to do a safe shutdown) (no filtering I believe, just basic UPS, It's an older model)

and I've just tried a Tripp Lite 4 outlets, 6ft cord, 3330 joules, All-metal housing with LED's - Isobar Surge Suppressor (ISOBAR4ULTRA) on the monitor system.
No change in the clicks. However, Im not sure how good this ac filter is. (borrowed from friend)

Thank you

[Lotus 7]

Originally Posted by bradp015

Just some more info:

I have a PC Back-UPS Pro® 1000 on some of the recording rig, (enough time to do a safe shutdown) (no filtering I believe, just basic UPS, It's an older model)

and I've just tried a Tripp Lite 4 outlets, 6ft cord, 3330 joules, All-metal housing with LED's - Isobar Surge Suppressor (ISOBAR4ULTRA) on the monitor system.
No change in the clicks. However, Im not sure how good this ac filter is. (borrowed from friend)

Thank you

That's an excellent filter which includes serious EMI and RFI filters, and should stop the noise from getting into whatever equipment that is plugged into it, unless the noise is actually riding on the ground leads. Have you tried unplugging all external devices from the mixer to see if the noise is still there? It should be possible to tell where it's getting into the mix. Is it still there if you turn down all channels and all AUX inputs?

Also please try the Tripp Lite on the flash unit. It will work both ways. If the flash is putting crap into the power lines, the Tripp Lite should drastically reduce it. If not, it's beginning to sound like it's radiated energy. Did you try the radio tuned to an open channel to listen for radiated noise.

[bradp015]

Originally Posted by Lotus 7

That's an excellent filter which includes serious EMI and RFI filters, and should stop the noise from getting into whatever equipment that is plugged into it, unless the noise is actually riding on the ground leads. Have you tried unplugging all external devices from the mixer to see if the noise is still there? It should be possible to tell where it's getting into the mix. Is it still there if you turn down all channels and all AUX inputs?

Also please try the Tripp Lite on the flash unit. It will work both ways. If the flash is putting crap into the power lines, the Tripp Lite should drastically reduce it. If not, it's beginning to sound like it's radiated energy. Did you try the radio tuned to an open channel to listen for radiated noise.

With just the monitors powered up, with out the outs from the console connected, all equip except for the monitors powered off, i get clicks in the monitors. The level trims on the monitors dont allow for gain to be reduced to infinity, so there is no way to turn the outputs of the amps down/off. so I would say, clicks are coming in from power, not sure what side, hot neutral or ground.

Q: for a test, if I lifted the ground on the monitors, would that tell me if the clicks are entering the system on the ground side? (or ground and neutral as they are bonded at the main breaker) Well, just typing that, It doesnt seem like a feasible test, since they are bonded anyway...(I never really understood the duplicate "earth ground". The neutral side is the same thing.)(may be showing my non understanding of electricity here, sorry)(I do know about the safety of the duplicate "ground" when having a hot fault to ground with a broken neutral tho)

I did try the am radio, ha ha, it had a digital tuner, doesnt let you tune to a open fq!!! Imagine my surprise! Looking for an analog tuner...

Thank you!

[Lotus 7]

Whew, that's really nasty interference if it's getting into just the monitors by themselves. It sounds like it must be getting in via the power line but may also be getting in via RFI. The Adams are well shielded, so that's really a long shot.

Noise being caused by the voltage drop during recharge is pretty unlikely too, since that flash unit is actually a pretty low powered unit as those things go. The unit your photographer has is only 300 watt/seconds capacity. Many modern line-powered flash units run at 1200 or 1500 watt/seconds today. I found a manual for it and it's fused at 5 amps but can have a instantaneous surge current of up to 10 amps max.. That should not be causing any problems with anything like decent wiring.

1. Try the Tripp Lite filter again on just the monitors.

2. Disconnect the input cables and put a small piece of wire in the monitor XLR input connector to short pins 2 & 3 together. Be sure the subwoofer cables are also disconnected.

3. Just for diagnostic testing you can try a 3-wire to 2-wire line cord adapter to float the ground pins on one of the speaker IEC power cords. That will isolate one of the Adams from the power line ground connection. USE CAUTION. Just plug a speaker into the 3-wire to 2-wire adapter and then plug the adapter into a power outlet. Don't touch the speaker and anything which is grounded at the same time. Floating a power ground is not safe and should be done very carefully. It's very unlikely that a Adam monitor will have any leakage current, but anything is possible. Disconnect the line adapter immediately after performing the test.

Again, if you can, try the Tripp Lite filter on the flash power supply.

[bradp015]

Originally Posted by Lotus 7

Whew, that's really nasty interference if it's getting into just the monitors by themselves. It sounds like it must be getting in via the power line but may also be getting in via RFI. The Adams are well shielded, so that's really a long shot.

Noise being caused by the voltage drop during recharge is pretty unlikely too, since that flash unit is actually a pretty low powered unit as those things go. The unit your photographer has is only 300 watt/seconds capacity. Many modern line-powered flash units run at 1200 or 1500 watt/seconds today. I found a manual for it and it's fused at 5 amps but can have a instantaneous surge current of up to 10 amps max.. That should not be causing any problems with anything like decent wiring.

1. Try the Tripp Lite filter again on just the monitors.

2. Disconnect the input cables and put a small piece of wire in the monitor XLR input connector to short pins 2 & 3 together. Be sure the subwoofer cables are also disconnected.

3. Just for diagnostic testing you can try a 3-wire to 2-wire line cord adapter to float the ground pins on one of the speaker IEC power cords. That will isolate one of the Adams from the power line ground connection. USE CAUTION. Just plug a speaker into the 3-wire to 2-wire adapter and then plug the adapter into a power outlet. Don't touch the speaker and anything which is grounded at the same time. Floating a power ground is not safe and should be done very carefully. It's very unlikely that a Adam monitor will have any leakage current, but anything is possible. Disconnect the line adapter immediately after performing the test.

Again, if you can, try the Tripp Lite filter on the flash power supply.

I will try this test...

OT: Lotus, What do you think about me looking on ebay for an oscilloscope?
I would not know what features to search for, to do AC testing. Would you be willing to do a quick search for me? and send some links to appropriate units?
If you dont have time for this, no prob., I'm still searching for someone around here with one)(just a thought here)

[Richard Crowley]

I would NOT recommend probing around the power mains if you don't know what you are doing. It is potentially dangerous (to both equipment and personnel) even for experienced engineers to probe the power mains.

I can't see how purchasing an oscilloscope is going to help resolve this problem. The equivalent $$$ would be much better hiring an experienced professional to connect a power line monitoring/logging device for a few days, and then interpreting the results.

[Lotus 7]

Originally Posted by bradp015

I will try this test...

OT: Lotus, What do you think about me looking on ebay for an oscilloscope?
I would not know what features to search for, to do AC testing. Would you be willing to do a quick search for me? and send some links to appropriate units?
If you dont have time for this, no prob., I'm still searching for someone around here with one)(just a thought here)

If you have a scope handy, connecting it between a known, clean earth ground might yield some useful info. Since you don't have one, it's certainly not worth buying one (just for this task) and learning how to interpret the readings.

Try to do tests I suggested, they won't cost anything and will give us a little bit more info. Especially try the line filter between the flash PS and the wall outlet.

So far we don't even know if the noise entry path is via the power feed to your audio gear or via RF or both.

It's especially troubling that it's getting into the monitors with nothing connected to them.

[Richard Crowley]

Originally Posted by Lotus 7

It's especially troubling that it's getting into the monitors with nothing connected to them.

I would find it troubling if the noise was getting into the monitors with the inputs TERMINATED. But with the inputs OPEN (disconnected), it doesn't seem that unexpected because it isn't really a valid test.

Ideally "terminated" means the + and - input nodes connected to a resistor of a value equivalent to the output impedance of the source. And the termination resistor would be shielded/screened (within a Faraday cage connected to ground). Alternatively, simply shorting the + and - nodes together would be more of a "valid" test than simply leaving the input OPEN. It is rarely valid to test or measure a circuit without proper termination of the input and output nodes.

[bradp015]

I tried to condense this as much as possible and still be specific and thorough in my observations, my apologies on it's length.
FLASH CLICK ISSUE TEST RESULTS

TRANSFORMER: iso transformer on console and monitors:
1. using tnsfrmr in CR on Tascam console and monitors: click present.
note:
The flash boxes have 2 faders, 1 for flash intensity, 1 for modeling light intensity (always on, but variable intensity)
When the model light is on, the flash box/bulb flicker every 5seconds or so, those clicks are audible in CR.
When the flash intensity fader is set to minimum, those clicks are farther apart in time.
When the flash intensity fader is set to maximum, those clicks happen much closer in time.
When model light is off, Flash intensity is full. clicks happen every 200-500ms or so. A lot quicker than when set to half flash intensity.

Disconnecting Audio interface (unabal.) from Tascam console: clicks are much lower.(connecting increases click volume a lot)
Disconnecting all unbalanced source/destinations from console: clicks very low but still audible.

2. using trnsfmer on flash boxes: clicks gone, can hear noise of recharge in monitors, very faint
-plugged 4 flash units into the txfrmr, no clicks, can hear the recharge faintly.
(with all studio equip. in normal settings, connected and powered on for normal use)

Mackie mixer substituted for Tascam console:
1. mackie connected to monitors: no channel inputs plugged into mackie. : no clicks
2. Unplugging the balanced lines going to monitors from mackie (at its outputs, with cables still plugged into monitors) faint clicks.


GROUND LIFT:
1. lift ground on monitors: clicks present
2. lift ground on flash: clicks present
3. Flash box with batter power only (no AC plug) no clicks.

LINE FILTER, tripp lite model

1. Connect filter on 2 flash boxes: click present

Uninterruptible Power Supply:
plugged in in CR for mac, HD and vid monitors only: when flash boxes powered on, I can hear faint clicks inside the UPS, sim. to the audible clicks in monitors.
These clicks are coming from the UPS itself, not the monitors. Unplugged mac, HD's, and vid monitor, same clicking in UPS.
Turning flash boxes off stops the clicking in the UPS.


Comments:
The unbalanced connection from the audio interface is problematic. However the console only has unabal. tape and channel line inputs. It does have balanced Mic inputs. I tried connecting Audio Interface outs to Mic inputs and got the same clicking as the unbalanced connection.

I find it odd that using the iso transformer on the studio equip. doesn't stop the clicking.

Even with the iso trnsfmr on the flash units, I can still here the recharger in the monitors. Acceptable, but still concerns me. Has to be more I can do about this.

Upon listening for the clicks, it was hard to determine if the clicks were there sometimes. (When I describe the clicks as "faint" in the above.) Due to background noise and noise floor (which is actually pretty low)

Tascam console has a CR section to control monitor level, when this pot is rotated from off to max, I hear clicks very similar to the flash clicks. I would say this pot is shot. Very dirty indeed.

Thank you all, for your input!

[brianroth]

curious....did you ever try the suggested test using a battery powered radio which covers the AM broadcast band to see if you hear garbage when the radio is tuned to the low end (540-640 kHz) of the band where there are no audible broadcasts?

I've found that to be a means to "find clues at the scene of the crime".

Bri

[Richard Crowley]

All this time I was assuming that the clicks were only happening when the flash is triggered (when he takes a photo). But now it sounds like the clicks are happening when the power supppy is "topping-off" the high-voltage charge in the photoflash capacitor bank. That is why it clicks more frequently at higher power settings. It also sounds confirmed that the noise is being TRANSMITTED via the lights' power connections, but it seems to be RECEIVED by the your signal wires (i.e. airborne) rather than through the power mains (which is why the filters at your end don't seem effective.)

Maybe time to consider the aluminum foil wallpaper again. :-) Although it also depends on the nature of the ceilings, also. If the wall between you goes up only into the attic, even if you had a solid mu-metal wall, interference can come in over the top.

[bradp015]

Originally Posted by brianroth

curious....did you ever try the suggested test using a battery powered radio which covers the AM broadcast band to see if you hear garbage when the radio is tuned to the low end (540-640 kHz) of the band where there are no audible broadcasts?

I've found that to be a means to "find clues at the scene of the crime".

Bri

Hi brian, yes I did try the am radio thing. I tuned to a low fq 500-600 inbetween stations. I got just pink noise. The flash system was in use by the photo guy. NO CLICKS! I tried this in different locations and turned the radio to physical attitudes.
thanks

[bradp015]

Originally Posted by rcrowley

All this time I was assuming that the clicks were only happening when the flash is triggered (when he takes a photo). But now it sounds like the clicks are happening when the power supppy is "topping-off" the high-voltage charge in the photoflash capacitor bank. That is why it clicks more frequently at higher power settings. It also sounds confirmed that the noise is being TRANSMITTED via the lights' power connections, but it seems to be RECEIVED by the your signal wires (i.e. airborne) rather than through the power mains (which is why the filters at your end don't seem effective.)

Maybe time to consider the aluminum foil wallpaper again. :-) Although it also depends on the nature of the ceilings, also. If the wall between you goes up only into the attic, even if you had a solid mu-metal wall, interference can come in over the top.

See am radio previous post.

I have found someone that will loan me an oscilliscope. He says he can show me the test proccedure for checking the sine on the main power. (but he is a dc guy mostly, airplane radio installation etc..)
I think I should check the power with it. thoughts?

I am going to ask a electrician about installing iso txmrs on the main power circuits that feed the flash units. the portable hospital grade ones are some bucks. And I would really need two, as the flash flash system is spaced all over the room. (abouts, 30x20)

No one has commented on using a balanced power unit for the CR.
Balanced Power from Equi=Tech -- The Son of Q for Pro Audio Applications
I'd like to hear some!

Alum Foil: eeek!, I cringe a bit when you say that. How bout alum. wallpaper?

[bradp015]

I only had a DDV with me yesterday.

What would you say if I said I thought I saw a Voltage dip on the flash triggers.

I wonder if my analog meter would would have a needle deflection on a .5 to 1V dip. And does that little of a dip matter.

I had thought I saw one of the CR outlets at 123V a one time, and 119.9 at another. Could be I didnt zero out meter.

Do you think a Voltage Regulator would make the "flash recharger noise" go away?
Furman AR-1215 Voltage Regulator at zZounds

[Ike Zimbel]

PHP Code:

"Mackie mixer substituted for Tascam console:
1. mackie connected to monitors: no channel inputs plugged into mackie. : no clicks
2. Unplugging the balanced lines going to monitors from mackie (at its outputs, with cables still plugged into monitors) faint clicks." 


I think this, coupled with the fact that using the iso transformer on the flash units helped, speaks to a susceptibility issue with the Tascam console. Love em' or hate em', Mackie consoles have always had their Pin-1 and shielding issues together, with all jacks grounding directly to the steel chassis. I don't know the Tascam desk, but most Japanese made desks, even ones that have the Pin-1 thing together (Yamaha, Ramsa for example) use plastic jacks that use machine screws, sometimes 1 screw per pair of jacks, to make the chassis ground connection. It may also have an aluminum chassis. It's been my experience that steel is more effective at blocking radiated noise than aluminum. In any case, it would be worth the time to check that all chassis and jack screws on the Tascam are tight. I have seen "Pin-1 problems" emerge on consoles that don't have the Pin-1 problem (Yamaha PM-4000, PM-3500 for example) because the jack and or chassis screws were loose or missing. Think of the chassis as the roll-cage on a racing car...it has to be intact to protect the insides properly.
Best,
Ike

[bradp015]

Originally Posted by Ike Zimbel

[PHP]

I think this, coupled with the fact that using the iso transformer on the flash units helped, speaks to a susceptibility issue with the Tascam console. Love em' or hate em', Mackie consoles have always had their Pin-1 and shielding issues together, with all jacks grounding directly to the steel chassis. I don't know the Tascam desk, but most Japanese made desks, even ones that have the Pin-1 thing together (Yamaha, Ramsa for example) use plastic jacks that use machine screws, sometimes 1 screw per pair of jacks, to make the chassis ground connection. It may also have an aluminum chassis. It's been my experience that steel is more effective at blocking radiated noise than aluminum. In any case, it would be worth the time to check that all chassis and jack screws on the Tascam are tight. I have seen "Pin-1 problems" emerge on consoles that don't have the Pin-1 problem (Yamaha PM-4000, PM-3500 for example) because the jack and or chassis screws were loose or missing. Think of the chassis as the roll-cage on a racing car...it has to be intact to protect the insides properly.
Best,
Ike

I should add that when the audio interface was connected to the chan input of the mackie, no clicks. When I plugged it into the rca "tape inputs", I did get clicks. Sorry, my description in orig posts should of included this info.
Aside from that, I do think the tascam console has it's own grounding issues.
Agreed on that point.

[bradp015]

Today, I disconnected the earth ground on the panel that feeds the flash boxes. Click were still present in the CR.
I measure this ground as well, near 0 ohms.

I disconnected the earth ground from the studio main entrance. clicks present.
This ground is measured at 1 ohm.

I separated the flash main panel ground from the studio main panel ground: Flash earth ground going to the town water supply pipes. The studio earth main ground going to the 4 ground rods. Clicks present.

thank you guys!

[Frost]

Breakers on neutral and hot in a non balanced system will never pass inspection today. In some states it might if the two breakers are connected permanently but not in IL Wi or Mi. And nec code says this is a bad idea.

[Frost]

To the main topic, what's the resistance between your ground and their ground? How about between your neutral and their neutral?

[Ike Zimbel]

Originally Posted by bradp015

I should add that when the audio interface was connected to the chan input of the mackie, no clicks. When I plugged it into the rca "tape inputs", I did get clicks. Sorry, my description in orig posts should of included this info.
Aside from that, I do think the tascam console has it's own grounding issues.
Agreed on that point.

Aha! The RCA's on the Mackie are the one exception to the rule. They are grounded via the screw that is between the two jacks.
iz

[bradp015]

Originally Posted by Frost

To the main topic, what's the resistance between your ground and their ground? How about between your neutral and their neutral?

What "should" the resistance be?
Considering the resistance between the panel grounds and earth ground was very low, I would expect btwn the 2 panel grounds and neutrals would be very low as well? sound right?

"Breakers on neutral and hot in a non balanced system will never pass inspection today."

can you clarify? Your saying if I had both hot/neutral installed on breakers, it would not pass inspection.? (the panel is not installed that way, did I give that idea?) I'm not sure how that relates to my issue. Can you explain?

thanks

[bradp015]

Originally Posted by Ike Zimbel

Aha! The RCA's on the Mackie are the one exception to the rule. They are grounded via the screw that is between the two jacks.
iz

Ike, can you clarify? (the meaning of "grounded on screw btwn the two jacks")
(and how it relates to chassis ground?)

thanks

[bradp015]

I had posted:
Uninterruptible Power Supply:
plugged in in CR for mac, HD and vid monitors only: when flash boxes powered on, I can hear faint clicks inside the UPS, sim. to the audible clicks in monitors.
These clicks are coming from the UPS itself, not the monitors. Unplugged mac, HD's, and vid monitor, same clicking in UPS.
Turning flash boxes off stops the clicking in the UPS.

Any ideas on why this is happening, and from what component inside the UPS?

thanks

[Frost]

If there is a breaker on the hot and another on the neutral line it's dangerous. You could flip a neutral breaker and gear would turn off but if you tried to work on the line you would still have a hot leg. If not I could have misread.

You said the neighbors panel was on city water ground and you were on a copper rod. The resistance should be high to infinite between them. If not move grounding rod. Neutrals should be near infinity also if not you are technically speaking bonding neutral to ground in more than one place which is not great for a host of reasons.

Another test, unhook monitors from board, do they still click? Cover with heavy foil, do they still click? Use a cheater plug for testing only to remove ground from speaker. Do they click? If all of the above still has clicking its probably in the neutral.

Finally maybe your speaker psu just doesn't have enough filtering if other speakers are not having the same problem.

[Frost]

Sorry was typing when u posted the above post. No idea what's clicking in the ups.

[Richard Crowley]

Originally Posted by Frost

If there is a breaker on the hot and another on the neutral line it's dangerous. You could flip a neutral breaker and gear would turn off but if you tried to work on the line you would still have a hot leg. If not I could have misread.

Absolutely correct. For a 115V ordinary circuit, only the "hot" side is protected with a breaker or GFCI. Green-wire ground is ALWAYS permanently connected to earth ground, and white-wire neutral is bonded to green-wire ground in the breaker/distribution panel. A 230V circuit is actually two 115V circuits "back-to-back" and both black wires are hot, and are protected with a 2-pole breaker. (Colors used in this example are North American standard. European would be green/yellow for safety ground, brown for neutral, and light blue for "hot".)

You said the neighbors panel was on city water ground and you were on a copper rod. The resistance should be high to infinite between them. If not move grounding rod.

I think you mean zero, not infinity. In a perfect world ALL the green wire grounds and white-wire neutrals would be exactly 0.0000 ohms to earth. In the real world there may be several ohms between ground/neutral and earth. Of course you go for the lowest number possible.

Neutrals should be near infinity also if not you are technically speaking bonding neutral to ground in more than one place which is not great for a host of reasons.

Again I think zero is meant vs. infinity. And very true that the white wire neutral and green-wire ground should be bonded ONLY in one place (in the breaker/distribution panel).

Another test, unhook monitors from board, do they still click? Cover with heavy foil, do they still click? Use a cheater plug for testing only to remove ground from speaker. Do they click? If all of the above still has clicking its probably in the neutral.

Indeed, you are making the same point I did a few rounds back. Testing the monitors with the inputs "flopping around in the breeze" (i.e. unterminated) is NOT a valid test.

Finally maybe your speaker psu just doesn't have enough filtering if other speakers are not having the same problem.

It is not clear what the issue may be with the monitor speakers (if there is any) because the test was not valid (inputs unterminated).

[bradp015]

Originally Posted by rcrowley

Indeed, you are making the same point I did a few rounds back. Testing the monitors with the inputs "flopping around in the breeze" (i.e. unterminated) is NOT a valid test.


It is not clear what the issue may be with the monitor speakers (if there is any) because the test was not valid (inputs unterminated).

Ok, I'm not sure why I can't get "do the terminated test with the monitors"
sorry, I will do this.

Regarding the "ground/neutral? bonded at more than one place. I plan on making a block diagram of my system. I'd like your thoughts on how the electrician did the install.

Advise: "ground to neutral bonding" If I want to test for "bootleg" ground condition (ground/neut connection not at panel) If I disconnect ground from panel on a branch circuit, measure resistance btwn ground/neut., will this tell me if they are connected somewhere on the branch circuit?
Q: Would this condition create an antennae situation?
(the tech panel is setup with IG, isolated(insulated) ground, 4 conductor)

thanks

[doulos30]

ask the guy to buy a iso transformer for his flasher then you buy a iso transformer for your console input if that doesn't work then physics has failed me. since you would be decoupling and isolating each end of the system.

[Ike Zimbel]

Originally Posted by bradp015

Ike, can you clarify? (the meaning of "grounded on screw btwn the two jacks")
(and how it relates to chassis ground?)

thanks

Usually, when you have a pair of RCA jacks or sometimes a group of four jacks,
there will be a screw in the middle of the jacks that A) holds the jacks against the panel, and B) provides the chassis ground connection for the jacks by holding a metal plate (part of the jack structure) against the inside of the back panel. That's in contrast to all of the 1/4" jacks on the Mackie, which use the sleeve of the jack itself, fastened with a nut and washer directly to the back panel. This makes for a much better ground connection with more tension, more surface area, and no voids. Hope that's clear.
Best,
Ike