need quad receiver, adaptor, decoder....

[fec]

Hi - I was just given (for a quarter apiece) a huge collection of records. Some of them are quad. I'd like to buy a quad decoder, receiver, or anything that would allow me to fool around with these quead records. Don't know too much about this, so I don't want necessarily to spend a bunch of money. Thanks - Forrest

[lynnm]

A Dynaco QD-1 (original or more recent version can typically be found for under $50.00 and is an excellent way to experiment cheaply).

[HDBRbuilder]

First of all, you need to know what type of quad your records are encoded in. There were three types of quad-encoding used in those days: SQ matrix, QS matrix, and CD-4/Discrete.

In order to play ANY quad album, you would need either a receiver that has all three of these formats BUILT INTO it, or you would need to aquire a quad amp or receiver and buy the separate outboard decoder or demodulator units to play these different format albums. In addition to this requirement, in order to play CD-4/Discrete albums, your turntable needs to be equipped with a CD-4/discrete cartridge/stylus...and these are hard to come by...this is not necessary for QS or SQ matrix albums, but IS NECESSARY for CD-4 to operate correctly!

CD-4/Discrete was the ONLY TRUE 4 channel ever laid down on record albums...the other types were simply matrixes, which used a carrier signal to "tell" the decoder which signals from each channel were to be sent to the rear speakers. With CD-4/discrete, the rear channel signals were remodulated up to a higher bandwidth and then laid into the record tracks...this bandwidth is above the human range of hearing (IOW, whereas the left and right front signals are approximately 20-20,000 Hz, the rear channels are on the record grooves as around 25,000-45,000 Hz). In order to recover these left and right rear signals, they have to be run through a turntable cartridge that can effectively pick up these higher frequencies, then they have to be run through a CD-4 demodulator which will remodulate them down to their original bandwidth, and send them to the rear channels.

As for buying a receiver that can do all of this...my favorites are the Harman/Kardon 800+ and 900+ models...everything is built into them. All you need is a turntable and cartridge capable of CD-4 and you are all set to crank up the lava lamp, hang up the black light posters, and hear Jethro Tull's "Aqualung" album as you have never heard it before!!

[Gregorius]

Andy,

Nice to hear from you, how have you been?

I bought a Pioneer QX-949 Quad receiver at Goodwill for $14, and it works great. I don't have anything encoded in Quad so I really haven't used it except for 2-channel. I think it has all of the matrix's inside. It is a heavy receiver, about 40+ pounds, I think it cost $750 back in 1975.

Regards,

Greg

[lynnm]

Andy is correct regarding the accurate decoding of "Quad" signals....but trust me the Dynaquad does a decent job.

To test the Dynaquad concept - assuming you have an extra pair of speakers that are similar in efficiency to your mains.

Wire the front speakers as per normal

The rears will need a little weirdness in their hook up.

Connect the (-) terminals of the speakers together .

Run a line from Left (+) on the amp to Left (+) on the Left Rear speaker.

Run a line from Right (+) on the amp to Right (+) on the Right Rear speaker.

Do not make any connection to the (-) terminals on the amp. In any event the (-) circuit has already been completed via the normal Front mains connection.

(Optional but worthwhile) Wire a 10-50 watt wirewound resistor with a value of about 10 ohms in one of the lines. The resistance value so long as it is kept low is far less important than that it be a wirewound type. A non-wirewound resistor will merely reduce the signal strength without introducing a delay into the signal path. The same effect can be achieved using an inductor but I do not have the foggiest notion of the reactance value in Mh would need to be.

[fec]

I appreciate the info so far...

I do have a Dynaco qd-2 and I am amazed at what the addition of the center channel does for my albums. I rarely hear much from the rear speakers, but I suspect it may be that they are not efficient (like the Fortesand heresy in front).

Iv'e never had or been exposed to quad. Eliminate cd-4 from the mix, since i have not and probably won't ever spend the money for a cartridge to play those.

I guess my specific questions are:

1) When playing qs for example, are there four equal channels, or is more like surround sound where the back channels provide "fill" or "ambience"?

2)Does the QD-2 do the same thing as a quad decoder ( like sansui for example) from the old days?

3) If I did have more efficient speakers in the back, would I get the same thing or something close to what an old qaud receiver or amp would have done? Or to get the full effect do you need the decoder and 4 channel amplification?

Thanks for your patience - -

[garymd]

Just saw this on ebay. Kenwood quad receiver item #3038068058.

The reason I was looking was because my local pennysaver had an add for a KR-9600 like the one I've owned since the late 70s. Great SS receiver and I was hoping to get it cheap. I'm taking a look tomorrow.

Kenwood made good stuff in the 70s and that quad may be what you're looking for. It's currently at $60. Good luck with your search but as I think Lynnm said, make sure it's compatible with your new albums.