Film-Tech Forum ARCHIVE: Dolby Digital equipment.

This is topic Dolby Digital equipment. in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Stephen Furley (Member # 1277) on 01-11-2003, 08:56 AM:

What is the difference between the DA-10 and the DA-20?

I think the difference between the soundheads is that the 699 had a separate rack mount power supply, the 700 had the power supply built in, and the 701 had an LED light source, is this correct?

Is there any likelyhood that early equipment will become available secondhand in the next few years at a price that I might be able to afford? (This means at a very price, I'm not a rich man) [Frown]

I would like to preserve an example of the system as it was when first introduced, and since most things digital seem to have quite short lifespans I'm not sure how nong they are going to be around for. Would anyone care to guess when this kit might become available for about 5-10% of its new price? Old analogue processors seem to keep quite a good value, does the digital stuff depreciate faster, or does the fact thatt there are still very many cinemas without digital keep the demand, and therefore the prices, for the older gear high?

How difficult is it to set up a digital system? I can do an alignment on an analogue system, but I have no idea what's involved with digital.

Posted by Gordon McLeod (Member # 33) on 01-11-2003, 10:14 AM:

The DA10 basically has more boards doing the functions that single chips are doing in the DA20

Posted by Aaron Sisemore (Member # 145) on 01-11-2003, 02:37 PM:

The Cat 699 had the external power supply, and a cooling fan for the lamp and a couple of extra rollers. The 700 had the power supply on-board, no cooling fan, and eliminated the unnecessary extra rollers. The 701 is the one with the LED instead of the incandescent lamp.

As far as 'setup' goes, you hook the reader to the decoder, and the decoder to the aux/digital inputs of the processor (if you are using a CP50 or CP55 you have to modify the processor some to get 5.1 digital to work properly).

Reader alignment for SRD requires a scope and optionally, the DRAS software running on a PC. The DA10/DA20/CP500/CP650 manual details the reader alignment procedure. Fortunately the Cat 699/700/701 do not require any real tweeking unless the reader has been tampered with or damaged in some way.

A suggestion: DTS is still the least expensive way to get into the digital game.

-Aaron

Posted by John Walsh (Member # 168) on 01-11-2003, 05:05 PM:

I think the "DA" and the reader are independent, that is you can plug in any reader (699, 700, or 701) into any DA unit (10 or 20.)

I was talking to someone at Dolby recently, and (offhand) they mentioned that a DA10 has a lot more processing power than a DA20. I'm guessing they overbuilt the DA10, but found later they didn't need all that power.

Posted by Bobby Henderson (Member # 840) on 01-11-2003, 09:37 PM:

Wasn't the DA-10 the original 1992 Dolby Digital playback model? The DA-20 wasn't introduced until early 1995. I would be surprised if the DA-10 had MORE processing power. The DA-20 and Cat No. 700 reader package seemed a bit more streamlined in design.

I remember talking to Rich Petersen about the differences between the two models. He ran the Casa Linda 4 and Astro Drive-In theaters in Dallas and was a partner in the West End Theater that used to be in downtown Dallas. Rich said they had all kinds of glitches with the the DA-10/Cat. No. 699 combination they had installed in the West End 10. He had two DA-20 systems put into the Casa Linda 4 theater in 1995 and regarding them as being far superior. From my own viewpoint as a humble movie watcher, I noticed fewer dropouts to analog --but, hell, that could be coming from any number of things.

Posted by Scott Norwood (Member # 30) on 01-11-2003, 11:14 PM:

Also, the DA-20 has the LED error count display and the DA-10 doesn't.

Posted by Mark Gulbrandsen (Member # 72) on 01-11-2003, 11:37 PM:

Its extremely doubtfult that the DA-10 had any more overall processing power than the DA-20. It had just to do the same job that the 20 does. The DA-20 utilizes alot of LSI type integrated circuits including the famous Zoran DSP processors. This allowed the DA-20 to accomodate only half the space inside the same mainframe. The power supply was also made smaller as the current demands were alot less. The DA-10 is really a dinosaur by todays standards...
Mark @ CLACO

Posted by Brad Miller (Member # 2) on 01-12-2003, 12:59 AM:

Bobby, dirt and projector abrasion can wreak havoc on SRD (SDDS too). I remember the West End 10 being an unfinished booth and particularly dusty. They also had incredibly dirty prints there. I'm betting anything that was the cause of their dropouts/reliability issue with the DA10/cat699.

I used the DA10/cat699 at Northpark and Hollywood, and we never had dropout issues at either place.

Posted by Joe Redifer (Member # 3) on 01-12-2003, 04:18 AM:

We had a few problems with the DA10 waaaaaaaaaay back in the day when it was around. Never any problems with a DA20. Never any problems with the Cat 699 reader, but a few problems with the 700. I wouldn't be surprised if the DA20 had slightly better AC-3 decoding amd error correction than the DA10. But who knows? Not me. Not yet.

Posted by Steve Guttag (Member # 268) on 01-12-2003, 10:20 AM:

The DA-10 DID have more processing power...it had more DSP power in it. What the DA-20 allowed was only having to pay for what you needed. The Zoran chips allow that since they were application specific (ASIC) as opposed to the (I believe) Motorola DSP chips that were general DSPs.

The DA-10 DID have an error thermometer just you had to know where it was! If you removed the front cover, one of the colums of LEDs (near the middle of the whole unit) would display the error rate...the LEDs would walk up or down to indicate the error rating such that no more than two LEDs in the column were lit at one time. How many LEDs were in the column? 8! Hence the DA-20 (and CP-500) only also count up to 8.

The DA-10 and DA-20 used the same input and output cards...only what came in between was different. As to the DA-10 being a dinosaur...it is on par in that department with the DA-20....they are of equivalent technology.

The DA-10 did have a potential fatal flaw, or so I'm told, it could download new software (via the film) once...on the next download to new software, it could get corrupted.

I must admit, I preferred our DA-10 at the Uptown to our DA-20...we generally never had DA-10 problems...in fact, we didn't have a power supply problem until Dolby came around and did a "free" upgrade to the DA-10. I know they changed the timing of the changeover between the time our DA-10 came out and the DA-20...mucked me up for a couple of shows after the new unit arrived.

In fact, I'd swear that the DA-10 kept better track of the operator's changeover command and not just the rigid time out like the DA-20. That is...with the DA-10...I never noticed any time where the sound was precisely tracking through a changeover...upon installing the DA-20...the operator had to adjust his/her delay to match the DA-20.

In my opinion, the DA-10 was a better unit but Dolby has dropped their support for it in the software department...hence they snapped them all up and replaced them with DA-20s.

The readers, as some have already mentioned...are completely interchangable...the DA-10/20 or CP-XXX don't know or care what is hooked up to it.

As to the penthouse readers...I much prefer the Cat. 699 film path...the Cat. 700's omission of rollers while fine for some is stupid for others. I prefer the Cat. 700 and later's more massive flywheel. I prefer the Cat. 700 and later...ability to adjust and optimize the performance of the CCD. Overall, the Cat 699 was a better built unit though.

Steve

Posted by Joe Redifer (Member # 3) on 01-12-2003, 11:40 AM:

I definitely agree about the Cat 699 reader. I liked the threading path much more and was a bit baffled when we got our first 700 in at the change.

Wow. This was a significant post that really contributed to the thread! [Smile]