Topic. Is any AC3 demodulator better than any other in terms of demodulation? Or do they all do the same thing, and output the same quality?

As I understand it, they all contain the exact same IC. Absent some severe error in power supply design or something, the actual demodulation should be identical over all models.

Publius,

you are fully right, all AC-3 RF Demodulators contain the PM4007A asic from Pioneer, this is the hart of the demodulator, remainder are the I/O and filtering circuits, so no difference in quality.

I have always wondered why Pioneer never integrated this circuit directly into their LaserDisc players.

Apparently, it was a cost issue. As in they thought their players were expensive enough! Adding the Demodulator would make it even more expensive.

As far as I know, the only player made with demodulator built in is the MSB LS-2X Silver, which is a souped up Panasonic LX-900u.

I have there are some legal reasons as Precision LaserDisc released an internal demodulator kit, and was shut down shortly thereafter.

Nice to know they are all the same. I have seen some people claim in the past that there is something special about the Pioneer RFD-1 over all others. Since this is the case it makes one wonder why there is such price disparity between the different brands of stand alone demodulators.

Some have more functions than others though like the transparent "pass-through" of the RFD-1.

A little more details on my eBay guide for AC3RF:

http://reviews.ebay.com/How-to-properly-handle-AC3-Dolby-Digital-on-Laserdisc_W0QQugidZ10000000010320266
https://www.lddb.com/help_ac3rf.php

Julien

Julien, I like the link with some information above

Because the technical specifications of Dolby Surround EX were not finalized when the first few EX LDs were released, your A/V Amp will not detect a 6.1 soundtrack but only 5.1. This is normal because the information flag that tells your system it actually is a Surround EX encoded soundtrack is missing. You will have to manually force the 6.1 mode to take full advantage of it.

I guess that also answers my question on the STAR WARS DVD with so called Dolby-EX It's only triggers the Yamaha RV-X650 I think only on "The Empire Strikes Back" while I have to ether manually switch it ON its like gimmick for Sensurround that had pulse code on the 35mm to trigger the Sensurround module to rumble the cinema or "Flag" well at least there's worked.



Hi publius

I think I have seen a thread I'm sure you started? Listing all AVR receivers with built in RF demodulators. But never mind that now. What about the standalone models the ones with this power issue can you list the ones that have the power issue and the ones that don't have power issues so I and others can at least remember in some part.

cheers

I've never heard of one which actually had such an issue. It was merely speculation on my part.

I see so its safe to buy just any model, providing I can find a sensible priced up model.

julien, you mention in your ebay page that the lexicon unit you had had issues? can you explain further? is there a common issue with these? you mentioned something about not locking to signal

Since I was living in Canada at that time, the shipping costs from US were not too bad, I took a chance on a seemingly nice unit.

Received it. It did power on but wouldn't lock on AC3RF signal => no output.

I had to negotiate hard -- the seller initially said I was a liar and a thief -- to make the seller admit that he had no idea what he was selling, that the friend who tested it for me just turned the power on and saw the LED coming to life. Had to pay for tracked shipping back to get my refund. He even implied that I was shipping him back a broken unit while keeping his unit for free (that's why you should note the serial number just in case). Had to escalate on eBay all the way.

I will pass on LDD-1 for now until I can test the unit myself first.

Julien

It looks like a nice one. It switches between rf and digital automaticly. It has a fine tune switch which i am not sure what it does or there is a need for it. But the reason why i realy like that one is its 17" wide,same as any component.

I just won the e-bay auction for a Sony SDP-E800 processor. I have been wanting one for years but was never able to afford it. This one I got for $20.50 with $19.00 for shipping. I hope it works okay. I won't know until I get it and test it. The main reason for getting it was its AC3-RF input.

Now, the next step is to either have the AC-3 output added to one of my players or buy a used player with the AC-3 output already installed (either factory or after market). Right now, a used player looks like the cheaper alternative.

Let us know how you like it as I have one of these as well. I just ordered a AC-3 mod kit for my CLD-97 and after I have that installed I will be trying it out myself.

I've heard more than one story about demodulators not being able to lock on to the AC-3 signal but functioning perfectly aside from that. Failed caps would certainly cause this. It would be nice to know which hardware is more or less reliable in this area because when you are buying old junk from eBay or Craigslist the person selling it often does not have the requisite mountain of hardware to test the AC-3 function.

I recently bought a Harmon Kardon DD processor for $40, much less than all the standalone demodulators I've seen on eBay recently. It only outputs multi-channel analog though, so you pretty much have to have a receiver from the same era to be able to use it. I'm hoping it functions when it gets here since this is the last thing I need for a DD LD setup. Also, I had to buy a boatload of interconnects to hook the thing up.

Is that the one which is the same as the Pioneer SP-D07, with the 4-channel audio inputs on the back for a MUSE decoder? If so, you got a good deal, in my opinion. I imported mine from Japan, which is a decision I find hard to justify, given that the same model was also sold here as the Elite SP-99D. I like it a great deal, though.

Nah, nothing so fancy. This is a ADP303. It wouldn't surprise me at all if it were a clone, but it has no MUSE functions. It mainly just turns DD (via AC-3, SPDIF, or TOSLINK) into six line level outputs. There are some trim and delay functions, but that's about it.

http://www.harmankardon.com/resources/B ... 3%20om.pdf

I received my Sony SDP-E800 digital surround processor yesterday. So far, all functions work on it with the exception of the AC-3 RF input. I have no way of testing that right now as I don't have a LD player with the AC-3 RF output. I tested the processor with a BD player playing a DVD with surround sound and it decodes the DD surround sound with no problems.

I will have to get used to this processor as it seems to do just about everything with the sound coming in from the digital inputs. It has Dolby, Movie, 3D, Music, Sports and Game genres. Each genre has from 1 to 10 modes. For example, the 3D genre has virtual enhanced A and B, virtual rear shift and multi rear(?) modes. The virtual enhanced A can create virtual rear speakers.

The processor has 3 digital inputs and 1 analog input. I am using digital 1 for my LD player, digital 2 is for my BD player, digital 3 is unused as it is audio only and the analog input is for an A/V switcher which has a CED player, LD player and VCR off it.

I just wished it would wash the windows for me (lol).

I also own this but I bought it to use solely as an AC3 demodulator. I have heard reviews that say the analog sound quality is pretty terrible on this unit and that it can have background noise with the analog output? Any troubles like this with your unit? I plan to use only the digital AC3 demodulator and then output the digital 5.1 signal directly to my receiver for decoding.

I bought a Lexicon LDD-1 some time ago. I had a chance to test it today. I used Star Trek Generations for ac-3 and Apollo 13 DTS to test pass-through. Overal I am very pleased. If there is a ac-3 track available, it locks to the signal and switches to RF in. If there is not ac-3 signal, then it switches to spdif digital. There is a front switch for digital coax and optical. you can connect 2 seperate digital sources (one optical, one coax) and use the front switch to select. There is also a calibration switch with 3 positions(normal, low and high), I tried all 3 which didnt alter the sound. Lexicon claims this is for timing of the signal. the manual has a chart for different manufacturers and which should be selected. My McIntosh is recommended at normal. It is about 17" wide, 2"high and about 4" deep. I placed it above my DVDO VP30 on the same shelf and my McIntosh is on the lower shelf by itself.