Film-Tech Forum ARCHIVE: Smart Mod VI alternative

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Posted by Bill Yacey (Member # 6102) on 06-15-2012, 11:40 AM:

I have a dead ModVI that I have traced the problem back to the matrix board. It appears Smart is defunct, and I haven't had a reply on my information requests.

Is there a similar product available from other companies?

Posted by Pete Naples (Member # 761) on 06-15-2012, 12:00 PM:

Not really is the short answer.

Ultra Stereo JSD80 is an excellent processor, will handle 35mm analogue and AES/EBU + SPDIF from digital sources.

Or you should be able to pick up a used Dolby CP55/65/500 or even CP650 for little, if any money.

Posted by Bill Yacey (Member # 6102) on 06-15-2012, 01:00 PM:

I can't seem to find anything at a reasonable cost. I just want to run stereo. Perhaps i could just use a 2 channel balanced mic preamp and a DBX PA driverack for EQ and X over.

Any thoughts on this?

Posted by Monte L Fullmer (Member # 2797) on 06-15-2012, 01:05 PM:

Can work, just no 4channel stereo.

Feed L/R solar cell feeds into mic imputs if the output leads are balanced.

Bet there are tonnage of CP 55's out there that can be had for a dime. But, do have a lead .. I'm sending you a PM or email.

-Monte

Posted by Paul Gordon (Member # 3320) on 06-15-2012, 01:16 PM:

There is a Cp-55 with cat 441 split surround card on ebay right now for a buy it now price of $125.00 You really can't go wrong with that.

Posted by Randy Stankey (Member # 64) on 06-15-2012, 03:12 PM:

Are any of the cards in the Mod VI common with the Mod 2B?

I've got a Mod 2B that's not being used. [Shrug]

Posted by Gordon McLeod (Member # 33) on 06-16-2012, 02:01 PM:

There are several matrix cards for the Mod6 usually the only ones with issues were the early DSP ones and often it was the 5volt rail of the powersupply
Contact Tom at Independent THeatre Supply in Edmonton we do have a few Mod 6 on the shelf

Posted by Bill Yacey (Member # 6102) on 06-16-2012, 11:52 PM:

I got the room up and running; I fed the reader head into a couple of balanced mic preamps and then to a 2 way active crossover, so I could drive the sub.

The reader is a BACP RSTR 2000. I noticed when setting the preamp gains there appears to be some high frequency distortion (fuzziness) in the audio, I was monitoring on headphones. I checked it with some different trailers and the feature that was scheduled to run in that room. I cleaned the reader head lens and the LED, adjusted focus for best high frequency response, but the distortion remains, both channels. I checked the lateral adjustment, but I didn't have my scope with me, so I just put it back to where it was, more or less centered, however it didn't improve in any way.

Any thoughts?

Posted by Tony Bandiera Jr (Member # 2365) on 06-18-2012, 12:26 AM:

quote:
The reader is a BACP RSTR 2000. I noticed when setting the preamp gains there appears to be some high frequency distortion (fuzziness) in the audio, I was monitoring on headphones. I checked it with some different trailers and the feature that was scheduled to run in that room. I cleaned the reader head lens and the LED, adjusted focus for best high frequency response, but the distortion remains, both channels. I checked the lateral adjustment, but I didn't have my scope with me, so I just put it back to where it was, more or less centered, however it didn't improve in any way.

I really cringe when I read about someone adjusting a reader without the proper test loops and without using a 'scope by "putting it back where it was, more or less". [Eek!]

Redo your reader adjustments properly, using a 'scope AND an RTA.

As for the HF "fuzziness" you need to make sure your reader's grounding is done EXACTLY as BACP instructs. The LED power supply is (and Sam will correct me if I am wrong) a HF "switch mode" type of supply and it can induce oscillation in the output of the reader if not grounded properly.

Or another (stronger) possibility: what you are hearing is HF artifacts because of the lack of proper Dolby NR decoding (most likely) or impedance/response mismatch because of using a non-standard preamp setup....or both.

Get a used CP55, 65 or 500 and do it right. Especially if this is a public venue. If it is for your personal screening room, no real harm in experimenting really.

Posted by Bill Yacey (Member # 6102) on 06-19-2012, 11:08 AM:

I don't believe it's supply noise. It comes and goes consistent with the high frequency content in the audio track, so most likely it's Dolby pre-emphasis.

At the time, I didn't think I could make it any worse, even though I didn't have a test loop or my scope with me. The focus was out considerably, after adjusting I was getting audio considerably higher than 3Khz, which is about all it was reproducing before. After centering the lateral adjustment as best I could, I now have pretty even balance between L and R channels, even if there is a little bit of phase shift. After adjusting, at least the audio quality is 80% better than what it was.

When I get back on site to install a new processor, I'll do a proper alignment.

Posted by Tony Bandiera Jr (Member # 2365) on 06-19-2012, 10:02 PM:

Bill, PM me if you're interested in a CP500 (with Dolby Digital installed) I have one just pulled from a screening room in good condition.