Quadrophonic receivers

amplifiers, receivers and loudspeakers
Adamo0926
senior member
senior member
United States of America
Posts: 520
Joined: 26 Feb 2011 03:22
Location: Connecticut

Quadrophonic receivers

Post by Adamo0926 » 01 Nov 2019 15:28

I see a few of these selling by good manufacturers like Sansui and are very reasonably priced.

Are they simply just 4 channel amps as opposed to 2 channel amps or is there something more to them ?

The reason I ask is because right now I am running my 4 original Advents in the stacked configuration. I have them
wired in parallel from my receiver (one pair to speaker terminals A and the 2nd pair to speaker terminals B).

Would there be any advantage using a 4 channel receiver to drive the stacked Advents compared to my current
setup ?

Tinkaroo
vinyl addict
vinyl addict
Canada
Posts: 7451
Joined: 04 Feb 2011 20:00
Location: Pixie Hollow by The Bay

Re: Quadrophonic receivers

Post by Tinkaroo » 01 Nov 2019 17:09

I would think it would work well in that application although they were originally meant for quadraphonic records and tapes.

The downside would be they are more complicated electronically with a lot more circuit boards, pots, etc. paced into one box. It's like having two stereo amps in one box. It could be used in quad mode or bridged for stereo which would give more power but then you are basically in the same position you are now as far as the application goes.

The more complicated circuitry makes them more difficult and costly to service.

The companies that built the better quality stereo receivers tended to build the better quality quads.

lenjack
long player
long player
Posts: 2005
Joined: 23 Jun 2017 02:11
Location: Liverpool,PA

Re: Quadrophonic receivers

Post by lenjack » 01 Nov 2019 18:18

The quad or 4 channel record thing was a major flop in the 70s, and I think you would find these receivers to be a major pain in the keister, as they were not well received, and many of them were problematic. Could cause you headaches. Advise caution.

PioneerFan
senior member
senior member
Posts: 288
Joined: 26 Jul 2016 15:00

Re: Quadrophonic receivers

Post by PioneerFan » 01 Nov 2019 19:31

For as long as I have been out thrifting for stereo gear, I have maybe spotted one Quad receiver out there in the wild. They really aren't that common.

KentT
long player
long player
Posts: 4485
Joined: 13 Mar 2008 19:44
Location: Athens, TN

Re: Quadrophonic receivers

Post by KentT » 07 Nov 2019 16:24

You spent more for a Quadraphonic model, and they were far less powerful on average than the Stereo offerings of comparable new price. A Sansui QRX-7500 or 7500A (a very expensive higher end model with both channels bridged together is only 35 watts/channel and listed for over $750 new in the USA) and weighs some 35 pounds. When this was new, you could buy most of the current two channel Stereo 100 watt/channel receiver offerings for this price or a bit less. A new 70 watt/Channel McIntosh MA 6100 integrated cost $695 new then. The cheaper Quadraphonic models often were 20 watts/channel or a good deal less powerful. Which limits the speaker choices you can drive them with. Also, the Quadraphonic receivers are more complicated to diagnose and repair.

bernard1
senior member
senior member
France
Posts: 574
Joined: 26 Aug 2016 19:06

Re: Quadrophonic receivers

Post by bernard1 » 07 Nov 2019 19:19

Grundig made a quadraphonic receiver in the 70's :
https://www.hifiengine.com/manual_libra ... 1040.shtml
My uncle has one. I think he never used it in quad mode :!:

KentT
long player
long player
Posts: 4485
Joined: 13 Mar 2008 19:44
Location: Athens, TN

Re: Quadrophonic receivers

Post by KentT » 08 Nov 2019 01:39

And it was lower end and SQ disc only. The few European companies who did Quadro were lower powered, 4 ohm loads, Your Grundig mentioned is very limited on what speakers it can drive. And expensive for that. It's nice looking.

jdjohn
long player
long player
United States of America
Posts: 2604
Joined: 20 Sep 2015 04:14
Location: Nashville, TN

Re: Quadrophonic receivers

Post by jdjohn » 08 Nov 2019 16:03

AND you would have to have an expensive Shibata stylus to play on the very limited selection of quad records out there. Quad was kind of the original 'surround sound'. The records were made in such a way that you could hear four separate channels if you had the proper equipment to 'decode' the records' output. And of course to really hear the effect, you would have to have two front speakers and two back ones. Your stacked Advents configuration would not really do it for ya.

lenjack
long player
long player
Posts: 2005
Joined: 23 Jun 2017 02:11
Location: Liverpool,PA

Re: Quadrophonic receivers

Post by lenjack » 08 Nov 2019 17:04

Well, you could add stacked Advents in the back. #-o =P~ [-o< :roll: :wink:

spensar
senior member
senior member
Canada
Posts: 742
Joined: 04 May 2014 02:40

Re: Quadrophonic receivers

Post by spensar » 08 Nov 2019 17:18

Some gear is marketed as quad but took 2 channels and made it into faux 4 channel, so it is buyer beware.

Adamo0926
senior member
senior member
United States of America
Posts: 520
Joined: 26 Feb 2011 03:22
Location: Connecticut

Re: Quadrophonic receivers

Post by Adamo0926 » 08 Nov 2019 18:15

lenjack wrote:
08 Nov 2019 17:04
Well, you could add stacked Advents in the back. #-o =P~ [-o< :roll: :wink:
hahahahah

lenjack
long player
long player
Posts: 2005
Joined: 23 Jun 2017 02:11
Location: Liverpool,PA

Re: Quadrophonic receivers

Post by lenjack » 08 Nov 2019 21:21

I've almost got you thinking about it. You'd never leave your listening room. There's an easier way, that doesn't require additional electronics. It's the Hafler Dynaquad circuit, developed by David Hafler, of Dynaco and the Hafler Company fame, in 1974, requiring only speaker wire and a potentiometer. You can use any rear speakers, or only one speaker. Ask Dr. Google for details. See http://techtalk.parts-express.com/forum ... ound-sound, for a simple diagram. There's also a simple upgrade involving a cheap Hafler Quadaptor. Just look up Hafler Dynaquad circuit. Fun to play with, and costs next to nothing. It recovers out of phase ambience information, present in the recording venue, the level of which, you control with the pot.

JoeE SP9
vinyl addict
vinyl addict
United States of America
Posts: 5088
Joined: 23 Feb 2009 19:20
Location: Phildelphia, Pennsylvania

Re: Quadrophonic receivers

Post by JoeE SP9 » 08 Nov 2019 22:56

jdjohn wrote:
08 Nov 2019 16:03
AND you would have to have an expensive Shibata stylus to play on the very limited selection of quad records out there. Quad was kind of the original 'surround sound'. The records were made in such a way that you could hear four separate channels if you had the proper equipment to 'decode' the records' output. And of course to really hear the effect, you would have to have two front speakers and two back ones. Your stacked Advents configuration would not really do it for ya.
For most quad recordings (matrixed QS or SQ) no special cartridge or stylus is needed. For QS or SQ encoded LP's an ordinary stereo cartridge is all you need. For the very few CD-4 recordings (discrete four channel) you need a quad cartridge W/Shibata stylus and a CD-4 decoder. The labels on all QS and SQ encoded LP's say Quadraphonic on the LP label and on the cover. For CD-4 LP's it usually says discrete 4 channel on the label and album cover

QS and SQ recordings respond quite favorably to a Dolby Pro-Logic decoder which is in all HT/Surround receivers.

FWIW: I tried SQ QS and a CD-4 decoder. That I got rid of them almost immediately should tell you something. A Dynaco Quadaptor is not really compatible with QS and SQ recordings. I didn't keep that very long either. I speak from actual experience.

lenjack
long player
long player
Posts: 2005
Joined: 23 Jun 2017 02:11
Location: Liverpool,PA

Re: Quadrophonic receivers

Post by lenjack » 08 Nov 2019 23:37

The thing about the Dynaco Quadaptor, or even the Dynaco quad circuit, without the quadaptor, is the simplicity, and the almost zero price. Nothing to lose. No special cart or stylus. Works with any source.

Bill_Ashton
senior member
senior member
Posts: 261
Joined: 05 Jan 2015 23:30

Re: Quadrophonic receivers

Post by Bill_Ashton » 09 Nov 2019 16:26

So, what kind of impedance load does a two channel receiver see with four speakers connected by the Hafler method? Must one run only 8 ohm speakers or could you mix 8 ohm and 4, or even use four r ohm speakers?

Obviously a quad unit with four amplifiers wouldn't care, but would a regular stereo piece go into protection mode?

Post Reply