Panasonic SA 6400X Quad Receiver?

[Superthrift]

Hello. My name is Mark, and I am new to this site. What has brought me here, is a nice Panasonic SA 6400X Receiver. I thrifted it the other day for $10. This unit has gone way beyond my expectations. How good of a unit is it overall? I have noticed a very faint hiss in the background. Otherwise flawless. I am not complaining for $10. Has the owners manuals, and balance control. I have not set it up for Quad use yet. -Thanks-

 

[sspsandy]

I have a similar model, the Technics SA6700X with the audio scope built in. The interesting feature of these units is the matrix decoder, which consists of two sliders. It allows you to adjust the width and depth of the decoding, similar to the panorama mode in newer Pro Logic II processors. I've always suspected that the decoder itself is based on the Variomatrix engineered by Sansui, since QS decoding was royalty free and Panasonic was another Japanese company.

Regardless, when both sliders are set all the way to the right it is in SQ mode, although to my ears it sounds like it sends the information equally to all 4 channels. Depending on the stereo source, adjusting the sliders will give better decoding with less artifacts. Another cool feature of the decoder is that it allows you to send any 4 channel information, such as CD-4 or info from a stand alone decoder, and process it through the built in decoder, allowing you to adjust the width and depth of the sound.

These units also have an early feature which gives you 90 degree phase offset (the Panasonic also has 180 degrees). This shifts the info going to the speakers so the front becomes the side (or the rears). I never use this feature.

As to the noise you are hearing, it is probably due to the age of the components. I had my receiver serviced by Classic Audio (.com) but could not get the capacitors replaced. Quad Bob might be willing to take it on, you'd need to ask him. It won't be cheap.

The decoder in theses units is decent compared to most of what was available at the time. It is no Tate, but is does a good job of creating pretty discrete separation. I've always wondered if there were blend resisters that could be removed to increase the separation, like in the Variomatrix models.

 

[Superthrift]

Thanks for the info. The hiss is very faint. I am not going to concern myself with it. I have a good tech in the area. For the money, I am very pleased. I doubt I would have difficulty reselling this unit for a profit. I think it is a keeper. What is Tate? I am always hearing a name I have never heard of. Thanks Again -Mark-

 

[sspsandy]

The Fosgate Tate II 101A was a high end wave matching logic decoder that was designed by Jim Fosgate at the tail end of the quad era (along with the Audionics Space & Image Composer, a very rare beast). They were originally over $1000.00 new, so not many were produced and sold. It is generally regarded as the best SQ decoder ever made. Around the same time Sansui developed the QRX 001 series of receivers with Variomatrix decoders, along with the QSD-1, QSD-2, and QSD-1000. These give the ultimate in QS (RM) decoding, and are regarded as the best for synthesizing surround from stereo, although the Tate does a fine job of it as well. Check the thread on the QQ Swap Meet and you will see a Tate that one of the QQ members has for sale.

 

[Q8Repair]

Nice score dude! I have a mint SA 8500X... I LOVE IT!

 

[Superthrift]

How much did you pay for the SA 8500X? I like this unit I have so much, that I will pursue a higher model. I have read that the Sansui QRX models had problems that the earlier QR models did not.
I did see a Harman/Kardon 150 on Epay for $150. Might get a bid. It seems to me you can get a nice quad unit at a much more reasonable price, than many regular 2 channel units. And Panasonic? I would have never thought that this unit would be this well made. I am guessing that it is 38 WPC in 2 Channel. -Mark-

 

[Q8Repair]

Panasonic= technics, FYI. As for going up a model.. I'm not sure you can. I think the SA-8500X was the top of the line in 76-77, and the 6000 series was top of the line in 78-79? I can't remember... there used to be a whole bunch of specs here:

http://vintagetechnics.com/

But for the past month I haven't been able to access this site. I hope it comes back, with all the pictures. Until then, you can use archive.org I think.

Yeah. Check out specs here:

http://web.archive.org/web/20060424082417/www.vintagetechnics.com/menu.htm

 

[sspsandy]

The thing to bear in mind with quad receivers is the decoders that are in them. The Harman Kardon is a nice powerful amp, but the decoder is not that great. Many of the receivers in the quad era had non or half logic decoders that offered only 3 dB of separation, not discrete at all. The Panasonic and Technics series that include the ones discussed here, all contain the Accoustic Fidelity Dimension decoder that is controlled by the 2 sliders. I have a copy of a brochure that describes it, it was pretty advanced for the era.

The QRX 001 Sansuis are excellent in the decoder department, but need to be overhauled by Quad Bob before they can be seriously useable. Certain of the later Lafayette receivers, and the SQ-W decoders are some of the best SQ decoders around. The Marantz quad receivers, which are powerful and well made, take a plug in decoder module, and the later ones, the SQA-2 and SQA-2B, were the full logic ones. They are rare and expensive, and still not as good as the other ones described here.

The rest of the quad era receivers, and integrated amps with preamp/decoders, were not very good at quad decoding. Some, like the Phase Linear 4000 amp and preamp, were beautiful and powerful, but you'd be better off using a separate decoder unit than the built in one. Even the half logic Sony SQD 2020 was better that the vast majority of them. Especially steer clear of Pioneer decoders, even though some of the receivers had cool looking scope like meters.

One of the nice features of the Panasonic SA 6400X and the 6700X is that they have three tape monitors. This allows you to run all manner of separate decoders (like the Tate that I have), demodulators, and in my case the fronts and rears from SACD and DVD-A players (I use a separate stereo amp in mono mode for the center channel). Add in a few switches and you can have a pretty cool home entertainment system run through the vintage quad receiver. And they are pretty powerful, mine is super loud at 3 on the volume dial. I also like the high and low filters, and the loudness button which brings old mono movies, VHS tapes, and lps to life.

 

[Superthrift]

Wow. Thanks for all the info. And I concur with the power. I have used a Pioneer SX 850, SX 650, Yamaha RX-V660, CR 620, and a Kenwood KA 7100 Integrated, and a KR 4050 that my Father bought new, and I like this unit better then all of them. None of them were quad as you know. I doubt I will be running a Television throught it anytime soon. But I was thinking about how neat it would be to do so. And Lafayette is an interesting one. Can someone recommend a model by them. Saw a mediocre condition LA 44 on Ebay. Sure had a lot of input/outputs.

 

[Q8Repair]

Yeah, but why bother with all those decoders? Just get a new technics surround/dts decoder, and move into the 20th century, sorta, with super heavy duty equipment. The only quad I'll probably ever play will be discrete quad 8 track.

 

[Superthrift]

Quad or not. For what I spent on this unit, and how good it sounds, I am very, very happy.

 

[Q8Repair]

Exactly. Post pics if you can... here's a few of mine:

It's PURRRRRTTYYYY.

 

[Superthrift]

Sorry. I do not have a Digital Camera. I have never posted a picture on the net. I would like to though. It's been hindering my ability to resell the stuff I have accumulated on either Ebay, or Craigslist. I think I may get one in the next week.
That is a nice looking unit. I was checking some of the photos of these, and input/output wise I prefer the Panasonic. I have checked and there are two units above the 6400X in the same model year. The one posted here, the 6700X, and the 6800X. I really don't think there is much difference between the three. 38, 45, and 53 WPC in two channel. Here is a link to a current auction of a 6400X on Ebay: http://cgi.ebay.com/ws/eBayISAPI.dl...MEWA:IT&viewitem=&item=160074996530&rd=1&rd=1. I wouldn't mind chasing down a 6800X, but Ebay is a waste of time, unless you find a good buy it now. I will not pay the absurd prices I see on Ebay. -Superthrift-

 

[sspsandy]

The main difference of the Technics SA-6700X is addition of the 4 channel audio occilloscope. Technics made good scopes, they also came as a separate unit. It's cool watching the X shaped wave forms as the music is playing, and it allows you to actually see the information going to the various channels, useful for seeing how your setup is working. The reality is that I don't use it that often, it is somewhat distracting when on for long periods, and you have to shut it off when not in use or it will burn a dot in the center of the screen.

If you follow the link here to Tab Patterson's website, he has video clips of various decoders run through a scope on a Marantz 4400 (one of the only other quad units with a built in scope, perhaps the only other one). The scope shows how well the various units separate the sound in the 4 channels.

 

[Superthrift]

I have never been a fan of something with a scope. @: All that is is groovy embellishment. And something to add unnecessary heat. Burning a dot in the center of the screen? Does the scope improve the sound quality? I wouldn't pass up on one at the local thrift, but I would not go out of my way to aquire one. The only difference is the 7 WPC between each of the three models, and a scope. That's not enough to make me pay a premium beyond what I spent. But that's me, I am sure somebody else would pay that premium. And I wish them the best in their decision.

 

[sspsandy]

I got a good deal on the unit, and the scope is fun. Like I said I don't use it all that often. I don't notice it getting hot. All scopes need to be shut off when not in use, when no music is playing only a dot appears in the center of the screen. It is my understanding that if you leave it on like that it is not good for it. It is a neat precision analogue device. I've always had an interest in things like occilloscopes, telescopes. microscopes, and telephoto equipment.

 

[Q8Repair]

Yeah, I have the component sized audioscope that panasonic offered, and I like it a lot. I don't use it much either, but it IS pretty awesome. It can help you 'tune' your system, or it can be used on special occasions, when you're really enjoying the music and are in a certain state of mind. Wink wink nudge nudge.

 

[ChristopherLees]

The QRX 001 Sansuis are excellent in the decoder department, but need to be overhauled by Quad Bob before they can be seriously useable.
.

since this thread is the fourth one found in google on a Quad Bob search... it needs to be currently updated ,it's now a long sad tale that will probably never end..

https://www.quadraphonicquad.com/fo...uadbob-has-not-returned-my-equipment-or-money

 

[w.a.reid]

hey thanks - yeah i dont think anyone would google bob herndon robert herndon quadbob or quad bob and not get these results - but on a side note - this thread is relevant for me - i have two of the technics sa6700x - and have all manuals and stuff for it if anyone needs to take a peak - i am missing a knob on one - and the other is with chris ready - doing a professional fix - a fix i wouldnt trust quad bob to do - for fear i would never get my machine back and my deposit would pay his electric bill.

 

[JonUrban]

I'll leave this thread open, but I would suggest doing some research before sending any equipment or money to ANYONE!!!