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In a pinch, you "could" use a pink noise test loop. Play the film and eq the center channel. You will have to turn the left and right amps off while doing the center channel. Short the right cell input to common to force the left channel to play and short the left cell to common to hear the right channel.

This technique was "developed" while working for a now defunct chain that often did not have the ability to get the test gear to arrive in a given location at the same time I was there! Ah! Memories!

The scope does connect to the left and right main outputs on the processor.

Oscar should catch this thread soon and will know exactly what to do.

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Sorry it took me so long to pick up on this topic. I did not look at this forum or anything else on the web all weekend.

The SR300 was designed sometime in the early 80's, and it was not the most convenient product in terms of setup. However, it was a popular product that allowed many theaters to have stereo who could not otherwise afford the higher priced brand. There are still very many in use today, even though the product was discontinued around 1985.

Regarding the a-chain scope hookup, there were no test points available, a serious oversight. However, if you have some small grabber clips on your scope test leads, you can try clipping on the right hand terminal of each of the preamp gain trimpots which are accessible behind the left hand security cover on the front panel. These are hard to get hold of, but these points will give you access to the preamp signals before they go through the trimpots. These are good places to look at soundhead alignment for checking focus and azimuth.

You can inject pink noise directly into the EQ600 inputs after first removing the input leads from the EQ600. Instead of removing the EQ600 input leads, you can just ground the MUTE terminal on the SR300 which will effectively disconnect the inputs to the EQ600. One of these techniques is necessary to avoid loading down the pink noise generator with the low output impedance of the SR300. Then just eq as you normally would.

Another method is to put the SR300 in MAG format and inject the pink noise into the SYSTEM IN terminals on the SR300. If you use this method then the SR300 MASTER FADER and output trimpots will affect the house pink noise levels. Again, do the eq as you normally would.

You may also want to download the SR300 manual from the SMART website if you do not have one. It is available at
http://www.smartdev.com/pdf/sr300.pdf

Thanks to all for the other suggestions made here. And MANY thanks to Mark and Stan for the kind comments.

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Oscar Neundorfer
Chief Engineer
SMART Devices, Inc.

oscar@smartdev.com

Personally I would stay far, far, away from the real old Smart processors. Anything MODII and later are excellent processors for those on a budget!

Aaron
http://www.cinema-west.com

No offense taken. However, even though the SR300 left a lot to be desired, noise was not typically a problem, your experience to the contrary. Considering the hum and noise problems you had, I am not surprised at your opinion of this product. I can honestly say that I have heard a number of systems that used SR300's, and they were as quiet as anything else out there at the time.

There is a jumper inside near the right rear corner that connected the circuit ground to the chassis ground. Sometimes this jumper could be cut to eliminate ground loops which caused hum. This was not directly the fault of the SR300, but rather it was a system problem.

The SR300 also had some problems with rigid header connections between the main board and the back panel board which could get intermittent and cause crackling and pop noises. We updated the product with flexible headers which pretty much solved that problem.

We offered several updates over the years to improve the reliability and quality of the product.

I am not trying to change your mind or rationalize the problems you have seen, but I do want you to know that many customers did not experience the problems you have witnessed. And for many customers, the product did a more than acceptable job of providing a decent stereo capability where price was a consideration.

What amazes me is that more than 18 years after its introduction, there are still quite a few out there working every day. Heck, we still have SR130's out there working every day, and that product is even older. And in case anyone is wondering, we still support and repair these old products although I for one am in favor of discontinuing support for these antiques.

Come on, guys, buy something new!

Best regards,

------------------
Oscar Neundorfer
Chief Engineer
SMART Devices, Inc.

oscar@smartdev.com

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