Film-Tech Forum ARCHIVE: will is Oscilloscope work

This is topic will is Oscilloscope work in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Jeremy M Smith (Member # 4913) on 08-10-2008, 03:58 AM:

I am look at this http://cgi.ebay.com/Hameg-HM303-6-35MHz-Dual-Chan nel-Trace-Oscilloscope-H9_W0QQitemZ200244666475QQcmdZViewItem?hash=item200244666475&_trkparms=39%3A1%7C66%3A2%7C65%3A15&_trksid=p3286.c0.m14.l1318

so I can do my own a-chain allignment would this work or do i need a 100mhz one

Posted by John Wilson (Member # 269) on 08-10-2008, 04:09 AM:

You know that's in New York, right? They are heavy buggers so go see the bank right now for the loan to pay for the shipping.

No offence Jeremy, but if you have to ask if it will do the job, do you really think you should be messing around with the sensitive adjustments on your machinery?

Posted by Jeremy M Smith (Member # 4913) on 08-10-2008, 04:30 AM:

No offence taken I have had people show me what i need to do. my boss just doesn't want to fork out $1000nz for a Oscilloscope. thanks for your concern. It is a really hard time for the movie industry of here in NZ not sure if it is the same over there so I am trying to save money anywhere I can.

Posted by Randy Stankey (Member # 64) on 08-10-2008, 09:19 AM:

1) It will work. 20 MHz would be enough.

2) If you decide to do your own work, be DAMN SURE you study everything you possibly can BEFORE you start fooling around.
Most bosses will be happy if you can fix the projectors and make them better but they will be VERY unhappy if you fuck things up!
If you have the process 100% fixed in your mind and you are certain you can do the job correctly and you can do it correctly the first time, go ahead and do it. But, if there is any possibility that you could fuck things up, don't even try.

3) It will cost you at least $75.00 US to ship to Australia. Add that do the $15.00 it already costs to win the auction and you're at $90.00 already. I wouldn't be surprised if your total cost is $150.00 or better once you get the thing shipped and insured.

Posted by John Wilson (Member # 269) on 08-10-2008, 10:24 AM:

quote: Randy Stankey
It will cost you at least $75.00 US to ship to Australia.

And then probably a bit more to get it to New Zealand. [Wink]

Posted by Mark Gulbrandsen (Member # 72) on 08-10-2008, 10:25 AM:

quote: Randy Stankey
1) It will work. 20 MHz would be enough.

Dolby actually recommends a 60mhz for working with SRD. Don't you guys have E-Bay over Australia? Shipping would be far less than from NY. Thats also not a very decent grade of scope and should you pay for one to be shipped over from that distance I suggest spending a few hundred US dollars to get a decent used Tektronix 4XX series scope. The 465B is built like a tank and lasts forever. Min's been battering around in the back of the service van for going on 10 years now. I also have the roll around cart and I use it in maintainance in big plex's where I have to knock out alot of A-Chains in just a few hours time. Both scope and analyzer are set up on the cart and I just go at it. Don't forget you'll need some sort of 1/3 octave audio spectrum analyzer as well...
Ebay Tektronix 465B Shopping Link

Posted by John Wilson (Member # 269) on 08-10-2008, 10:34 AM:

quote: Mark Gulbrandsen
Don't you guys have E-Bay over Australia?

Yes we do.

They even have a New Zealand version of eBay which (as you'll see by his profile) is where Jeremy is. [Razz]

(We Aussies like to be confused with New Zealand about as much as someone from the USA likes to be confused with a Canadian or vice versa.)

Chances of finding one on either .au or .nz are pretty slim I'd imagine. Better to look at absorbing the potential cost of $150 and buy something locally...even if it's new. [Razz]

Posted by Louis Bornwasser (Member # 3063) on 08-10-2008, 08:46 PM:

Mark is right on this one. We have found that the higher numbers (60Mhz 100Mhz) also give a brighter picture; very important if you are old and eyesight isn't what it once was. Louis

Posted by Steve Guttag (Member # 268) on 08-10-2008, 09:21 PM:

I have set up many a DD reader with a 20MHz scope. Since one is doing a relative measurement...kinda like focusing an image, you can tell when it is best.

That said, everything is much more crystal clear with a 100MHz scope...which I now use in the field as well as the shop.

Steve

Posted by Jeremy M Smith (Member # 4913) on 08-11-2008, 06:25 AM:

"1/3 octave audio spectrum analyzer"

this is only for b chain right?

Posted by James Falloon (Member # 1933) on 08-11-2008, 06:36 AM:

Hi Jeremy

There are a few on trade me (New Zealands own version of eBay) keep an eye out on there, it's easier to get one already here than importing one, also don't forget you may have to pay GST on it as well if you are bringing it into the country.

Also listen to Randy, it's not what you know but what you don't know that will land you in hot water.

Getting the sound fixed is your bosses problem, if he doesn't want to fork out to fix it well it's not your problem, crappy sound it shall be. (side note: I believe its attitudes like that that got the industry into the pickle that it's in). will you be getting paid extra to use your gear to fix your bosses sound? what if something unforeseen does go horribly wrong? then what?

I don't take my scope into work, I leave allignments up to the professionals, who have all the proper tools and experience and know what they're doing, and my hands are clean if it does all turn to crap.

I know it sucks, I too care about presentation but it's just not worth me taking the risk, a noble gesture none the less.

Posted by Kenneth Wuepper (Member # 1174) on 08-11-2008, 08:45 AM:

Jeremy,

The spectrum analyzer is also used for proper "A" chain alignment. It is possible to see the high frequency response on the analyzer and the phase relationship of the channels on the oscilloscope. Those tools and the proper film loops are essential for proper and complete alignment of the "A" chain.

The "B" chain is the fitting of the sound into the auditorium and provides the opportunity to make some correction for the acoustics. The best solution to acoustics is to correct the room and do as little to the system equalization as possible.

There is no magical approach to booth maintenance but observation of professionals and studying the manufacturer's manuals is how you will learn. Experimentation on operating equipment owned by someone else is very risky. You have everything to lose and little to gain by experimenting with other people's equipment.

KEN [Wink]

Posted by Jeremy M Smith (Member # 4913) on 08-12-2008, 08:55 AM:

thanks for all the comments it has given me a lot to think about. I have many things to fix at the moment but I will look into this in the near future. Our cinema is falling apart at the moment. so many things the place hasn't had maintenance on the only thing that has is the sound. thanks to technicians that when thing do go bung I can call on. Just need to try and get the booth flowing again.

Posted by Gordon McLeod (Member # 33) on 08-12-2008, 04:43 PM:

Has anyone tried this item
http://www.ezembedded.com/product_info.php?products_id=35

Posted by Mark Gulbrandsen (Member # 72) on 08-12-2008, 06:41 PM:

Gord,

Thats an interesting scope add on for a laptop and it actually has useful bandwidth... I have to wonder though if the USB connection is actually capable of that bandwidth or not.

Mark

Posted by Jeremy M Smith (Member # 4913) on 08-12-2008, 06:49 PM:

Looks cool my only concern is will it work seems kind of cheap for a digital Oscilloscope isn't it?

[ 08-12-2008, 09:54 PM: Message edited by: Jeremy M Smith ]