Marantz DP-870 RF Demodulator

In order to get Dobly Digital 5.1 sound out of a Laserdisc player, you need two things. First you need a player that is capable of outputting an AC-3 signal (AC-3 is the old school name for Dolby Digital) and a RF demodulator to decode that signal. My Pioneer CLD-704 Laserdisc player is AC-3 capable so I needed a RF demodulator. They don’t sell RF demodulators anymore so you are forced to look for used ones. They often pop up on eBay so if you need to get one that is a good place to look. I happened to have been able to find one locally through the classifieds and I got it for a great price too.

The problem for me with most RF demodulators is that in order to get the sound from them into your receiver you need a set of analog 5.1 inputs. My receiver has a single set of 5.1 inputs but I have two devices that need one. The Marantz DP-870 and my Pioneer DV-45A SACD/DVD-A player. This is the main reason I picked the DP-870; it has a set of 5.1 inputs, most of the other RF demodulators do not. So I run the output from my Pioneer DV-45A into the Marantz’s 5.1 inputs and then run the output from the Marantz into my Outlaw 1050’s 5.1 inputs. I was a little worried about sound degradation due to running the Pioneer through the Marantz but the Marantz has a bypass mode. When you activate the bypass mode the input and output jacks are connected through relays which have no active circuits in them so if there is any sound degradation it is kept to the bare minimum.

I have been very happy with my Marantz. It doesn’t see a whole lot of use because I primarily watch DVDs, but when I break out a Dolby Digital Laserdisc it is nice being able to hear them in all of their 5.1 glory.

Marantz DP-870 Features/Specs

Comments & Questions

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7 Questions/Comments/Trackbacks so far

  1. Posted by: John Anderson
    October 1, 2009 9:57 pm

    How are you, I’ve got a bit of a story and also a question for you.
    My situation is similar to yours, around about 1999 I bought a marantz sr 96, no onboard DD decoding. And about two years ago I bought a Pioneer DVD/HDD recorder, when my old vcr finally crapped out. Once home I remembered back to ’99 and remembered that you have to have a seperate decoder to get DD, so I went back to the shop and asked to see/test a couple.
    This salesman looked at me with a confused look on his face and said “a what?”.
    A couple of months later I was getting really pissed off with having a flash dvd machine but no way of getting DD out of it. So I went and bought a Denon DVD1910 with 5.1 output on it.
    I don’t like it, it dosen’t fit with the rest of my system, and it’s as slow as buggery.
    I’m thinking of buying a second hand 870, getting rid of the Denon and running movies through the Pioneer DVD rec.
    What I don’t know, is wether the Denon, being 10 years newer might do a better job of DD than the DVD rec and a DD decoder?.
    I just dont know.
    What do you think?
    The pioneer rec was the top of the line model two years ago.
    Thanks for your time.
    Any help would be appreciated.

  2. Posted by: Moe
    October 2, 2009 9:38 am

    At this point in time if I were in your shoes I’d just bite the bullet and by a new receiver that did DD decoding. You can get a nice one for pretty cheap these days, especially if you don’t mind buying used, and it would just simplify your life.

    As to which would sound better, a separate DD decoder or a modern DVD player, I can’t say for sure but my money would be on a modern DVD player. I never used my Demodulator with a DVD player, I only used it for Laserdiscs since that was the only way to get 5.1 sound from a Laserdisc player.

    Good luck!

  3. Posted by: subhasd
    April 24, 2011 2:58 am

    i buy dp 870 marantz digital processor i hav no knowlegde plsz send me how to play

  4. Posted by: Kelly McClanahan
    October 30, 2012 8:35 am

    I bought a DP 870 Marantz thinking that I would eventually pair it with a Marantz SR 96. I had the idea that this would Explode my TV surround sound into something far superior to my present surround sound receiver. (Sony) I am now confused a little as to what the DP 870 does. Is it primarily for use on components such as Lazer disc or DVD players. If this is the case then woould it have little or no improvement over my present surround sound receiver when watching TV?
    Thank you

  5. Posted by: Edward Lin
    January 5, 2013 4:41 am


    I am interested in Marantz DP-870. Please let me know if it still available. Please drop me a note to my email address. I can provide my cell number if needed.

  6. Posted by: Ed De Oliveira
    August 24, 2014 9:31 pm

    Im so gladd I looked at your web site. I was shopping for a used AC3 demodulator on ebay when I came across this site and read your article on the Marantz DP-870. I had completely forgotten that I have one. I purchaced a new one like back in the 90s. I take very good care of my AV equipment so it is in pristeen condition. Now I can watch my collection of LD movies that I had put a side for Blu-Ray movies.
    I have heard from people that AC3 is still a great sound. I will test it and let you know.



  7. Posted by: Adit
    December 1, 2020 12:11 pm

    Hi,I have a Yamaha HTR-6063 receiver and pioneer Cld-D515 laserdisc player with AC-3Rf.
    My receiver doesn’t have AC-3RF.Do I need a AC-3 RF demodulator or a AC-3 decoder?
    Please let me know how to connect to get Dolby-digital sound when playing Dolby-digital encoded laserdisc.
    I have about 2000 movies on laserdisc and 60 of them have Dolby digital 5.1 and my st AC-3?