Home theater without a receiver

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Has anybody ever tried using the 5.1 outputs on a DVD player that is so equipped to supply discrete signals to three seperate stereo amps for home theater?

I want to use my tube amps for home theater and this seems to be a way of doing it without having to buy a DTS or Dolby Digital receiver or seperate preamp......

The question then becomes how to control six channels of amplification simultaneously.

Six in, six out. I can't think of anything with that capability that is readily available. I think I'll be stuck with three volume knobs.

All this would be possible with a DVD player like the Apex AD800(which we sell at the store) since it does have the six channel outputs. By the way, it's also a progressive scan machine with component video output, independent horizontal and vertical incremental zoom, and has a ton of other features, all for 150 bucks. A good unit for experimentation.......

Thought I'd throw this one out at y'all....

An alternative is to use an outboard decoder, such as the Technics SH-AC300 that I currently use. It has a single volume control that handles all six channels.

A more ambitious project (that I am in the midst of!) is to use such a decoder and upgrade the DACs.

BTW, how is the video quality on that Apex? I bought one of their earlier models but sold it shortly thereafter because the video decoding quality was very poor--a lot of blockiness that frankly drove me nuts. It was especially apparant in dark backgrounds or anime.
Hi tiroth-
We use these Apex's all around the store and we are generally pleased with the video on them.

I am curious what model Apex you had. There was one that had an interesting feature- a secret menu that allowed you to defeat the copyright protection. The FCC put a stop to that and they are now highly sought after. EBay won't allow anyone to sell them.

Apex went from nowhere to number two in DVD sales in the world in one year. Their products are loaded with features for the money, but you have to consider them on a model by model basis.

They have the first DVD that will play both SACD and DVD audio.

I would love to have an outboard decoder/preamp, but they go for as much as a receiver (or more).

Thanks for the reply!

By the way, I was born in New Castle.

Another former Pittsburgher. :)

Outlaw also makes a full featured decoder, I believe. You can generally pick up AC300s on Ebay for $50-$100. Actually a nice decoder...I measured THD+N to -95dB.

Yeah, I had one of those "highly sought after" ones...ended up selling it at a profit. ;) Thought it was terrible quality, even though most others didn't seem to think so. Maybe I've just trained myself to see artifacting though...I've dabbled quite a bit in digital video. I'll have to check out the new model...progressive for $150 sounds nice. Do you know what deinterlacer they are using?

You got me on the deinterlacer....
Is it a chip?

Actually this is an older model, but still current.

Interesting on that AC 300.
What type of digital input does it have?

It sounds like what I need, but I've never seen any preamps that cheap.

What I really need is a vacuum tube Dolby Digital decoder....

Yes, the deinterlacer is a chip. Some of the really nice progressive DVDs use the Faroudja FLI2200 IC, very nice, but hard to find stateside.

AC300 and AC500a have RCA and toslink digital inputs, the 300 only does Dolby Digital, the 500 does DTS as well. 300 has only analog pass-through (useless), not sure about 500.

If you check out the woefully underpopulated I/V section on my
DAC page you'll find a link to a tube I/V. Build your own DACs on top of the ACx00 or another decoder and you can put anything you want downstream. ;)

There is some useful info on the AC300 on my site as well:

Very interesting reading, even if it is a little over my head...

There's a couple of those 500s on eBay currently, so I'll keep an eye out for one. I appreciate your pointing them out to me. I've always been a Technics fan and it's kinda sad to see Panasonic dumping the brand name after 30 years. When you think about it, Japanese hifi has only been around for 40 years or so, making Technics one of the older names there....

I like the idea of bringing vacuum tubes to the home theater scene....multi channel sound, center channels and surround channels have been utilized in movie theaters since the thirties,and the heyday of Western Electric, so it's kinda retro(!)

Just one question- how many vacuum tubes would it take to construct a tube version of a Dolby Digital decoder??????


I am running surround w/out a reciever

I'm lucky enough to own a NAD T550 DVD player which comes w/ rca 5.1 outputs. I run my modded ST 70 for mains, a homebrew solid state for center/bass and an old crown amp for surrounds. I lack remote volume adjustments which make tweeking levels difficult, but I like the novelty and the sound doing it my way.
Well alton, I guess you beat me to this one!

I'm using an Apex with 5.1 outs.
The fronts use my Van Alstine mod ST-70.
The rears use my Triode Electronics mod ST-70.
The center is a mono amp out of a Hoffman console (6bq5).

The setup sounds awesome, although I can definitely tell all the sound is going through a chip(!)

I'm using my Voice of the Theaters up front with Altec Boleros (890C's) in the rear. I will eventually use my 604D's for center and surrounds.

Do you think five Altec 15" drivers will give me sufficient bass???

Rhetorical question--no need for a sub. I just set the output for full range speakers.

BTW, the latest Sound and Vision tested three powered subs and they were all down at least 3db at 50 cycles!!
I can only imagine where they are at 30.
The VOT's give me usable response below 25.

This is diy home theater at it's best-bare minimum circuitry and the type of speakers they really use in theaters.

Say tiroth--you got a schematic for that tube decoder??
I've got a pole barn I'm not using........


Say tiroth--
Just wanted to let you know that The Apex AD800 is performing very well, both on the 5.1 audio outputs and on the video.

I'm running component video out and I see no digital artifacts in the picture. My TV doesn't have 3:2 pulldown so there is some jerkiness in the motion, but no more than any other DVD player.

The mechanism and controls seem substantial and well made.

It's got tons of interesting fetaures like color, gamma (brightness), and x-y scaling (zoom) adjustments, remote switching to progressive scan and NTSC/PAL, and can even show you the bitrate flowing through it.

It's got a karaoke input, but I haven't played with that yet. My kid wants to see if he can run his guitar through the karaoke input so he can use my VOT's (loud!).

All in all, a neat machine. We sell them for 149 bucks. Not for the "menu challenged" but great for experimenters!

I used a Creative Labs Soundblaster LIVE! MP3 + 5.1 channels. This sound card doesn't have all the features that a decoder box has but it does have interesting features for sound fields. If only Creative Labs stop sitting on their hands and start including more features.

If anybody can design a USB dolby digital decoder box that uses sunfire amplifier technology for its pre-amp. Then I'm might consider to upgrade to that USB sound box.

Those decoder units that people suggested are good but compare each to see which one is good for you.
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There's a couple of those 500s on eBay currently, so I'll keep an eye out for one. I appreciate your pointing them out to me.

I have one of these and quite like it. There are some documented tweaks that improve its sonics (as yet not done in mine).


The amps i use are in semi-constant flux. Right now i'm using 2 NAD 7020s for fronts & sub (virtual centre) and an RS 4-channel pro-logic unit for surrounds. Soon the essential elements of my separate HT will be integrated with the main hifi, and then i'll have tubes on the fronts.

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