Film-Tech Forum ARCHIVE: Problems with distorted music w/Kintek sound system.

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Posted by Brad Allen (Member # 470) on 02-20-2008, 07:35 PM:

Please, no lectures about the poorness of this system. [Big Grin]

This is a center surround setup.

This setup was used successfully for several years. It was recently removed and installed in a differant situation and have the following problem.

When music is played on a film sound track, it has a raspy quality to it. I don't know how to better describe the sound.

NON-Sync sounds perfect, no problems.

Voices and other sounds from film sound track are near perfect. You can especially hear this trait in piano music. This system has two adjustments that are related to the sound reader. One is called Balance, manual discribes that this balances the output from each channel of the solar cell. In my case a Kelmar visible red light reader.
This is adjusted by turning on the sound reader LED, with no film in projector, and adjusting pot so that the BAL light is lit.

Then there is the setting of CAL, again, your suppose to adjust the pot for this indicator light to come on with sound reader on and no film in projector. I can't get this light to come on. I'm assuming this is an adjustment sort of like Dolby Level, to get the proper light level driving the pre-amp?

Can this be caused by the LED not being turned up bright enough?
See my other thread on the proper ma setting to use.
And I'm assuming this is possibly the cause of the "raspiness" to music.

Sound reader is a Kelmar Reverse Scan reader that was originally designed for IR LED, but was upgraded to a Visible LED.
Is it possible the Visible LED is not working correctly with the rest of the kit that was designed for IR LED?

Any suggestions or thoughts are greatly appreciated.
Thanks!

Posted by Steve Guttag (Member # 268) on 02-21-2008, 02:10 AM:

This is a known incompatibility with the Kintek/red reader set up. The Kintek preamp is looking for the DC offset caused by a typical solar cell to set its "CAL" level. As I recall, they used this DC offset to bias their 1st stage in the preamp, which was an unbalanced device. With a reverse scan red reader you have a pre-preamp that eliminates the DC offset...as such I don't think (though have not confirmed) you will ever get the preamp biased properly.

You could always try bypassing the preamp on the red reader and see if the Kintek preamp has enough gain to light the Cal light but I suspect not without significantly raising the LED intensity.

Whereas virtually every other form of optical preamp strips the DC offset off of a solar cell feed at the very first stage, this a problem almost only with Kintek.

Steve

Posted by Sam D. Chavez (Member # 1841) on 02-21-2008, 10:14 AM:

Steve, you are wrong. God, that is fun to say as the opportunity happens rarely.

The Red readers were all built to have a DC offset precisely for this reason. This was a Dolby requirement as mentioned in a related thread. This was a Lonny Jennings bow to General Cinema that had a lot of these installed. Sadly or not, both Kintek and GCC are long gone.

Now whether the reader works as anticipated is open to question as there a precious few Kintek's around to try out the feature.

Posted by Jack Ondracek (Member # 1466) on 02-21-2008, 10:33 AM:

Did kintek have slit lens correction? It's been Sooooo long, I don't remember. Wasn't there a pot next to the "cal" pot on the preamp? Even if there was a fixed curve in there you could have some trouble. High frequencies could be "hitting the rails" because of it, and that might be the cause of the brightness and splatter that Brad's hearing.

Posted by Jeremy Weigel (Member # 4208) on 02-21-2008, 12:09 PM:

Experienced the same raspiness or static like sound when we switched to red LED's (BACP) on our Kintek center/surround systems (KT-2010). Even though I was able to get CAL/BAL. I noticed it more when there seemed to be more high frequency in the soundtrack. Switching back to the original solar cell/exciter setup eliminated it, so I concluded it was an incompatibility issue. Figured it had to do with the better high frequency output of the LED's?

Anyway, it gave me a good reason to strongly suggest to the bosses to upgrade to newer/better equipment in those houses; which they did. I also had the same problem with the KT-700 we had, but it was, for some reason, not as noticable. Finally pulled it out of service last month.

Posted by Brad Allen (Member # 470) on 02-21-2008, 02:40 PM:

Thanks All, gives me some things to check on, but alas, it almost confirms my initial fears of the Kintek not playing nice with LED readers.

Posted by Steve Guttag (Member # 268) on 02-21-2008, 10:19 PM:

Sam,

While I don't have experience with your reader on the Kintek...I have witnessed other brands (CE comes to mind and I think Kelmar) NOT allow a CAL light and the sound was indeed distorted, regardless of level. Have you personally seen a production Kelmar or CE reader on a KT700 or KT2010?

On the KT-700 preamp, there was a "slit loss" of sorts...it behaved like a shelving filter so one could not really correct for slit loss but one could boost HF response.

Steve

Posted by Mike Spaeth (Member # 524) on 02-22-2008, 01:49 AM:

We figured that red LED time was a good excuse to junk the Kinteks and replace them with Ultra-Stereos. Easiest (and more expensive) solution!

Posted by Catalin Balaceanu (Member # 3712) on 02-22-2008, 03:45 AM:

I have the same issue with a ASR-40 CE reverse scan reader and a USL DSP-60 processor. It looks like the reader is way too sensitive to dust and scratches on the soundtrack. The better the reader is focused , the higher the dust/scratches noise. Fist I thought the processor is miss tracking, as the noise was obvious mostly during dialog. But listening to the signal straight at the test points of the processor, I noticed that the noise was present all the time while the movie was running. Pretty similar to the noise of an old, scratched vinyl record. Is there a way around this issue?(besides getting rid of the processor/reader and buy dolby)
Thanks

Catalin

Posted by Mark Gulbrandsen (Member # 72) on 02-22-2008, 08:45 AM:

There has been bad engineering, poor enmgineering and faulty engineering and Kintek is certainly the best example of the latter. One would certainly be better off with any OTHER used piece of equipment... even a used USL JS Series or a Smart Mod 7 or 8 on the cheap!!! I would highly reccomend the new USL JSD-80... The last Kintek system I removed was promptly taken to the rifle range and shot to pieces... It got what it deserved!

Mark