DYNACO QUADAPTOR schematic

[Guest spgjmf]

hi all,

I normally read the AR forum, but

have become interested in the quadaptor.

As Iunderstand it, its a passive device to create 2 more channels of

audio from the main stereo channels - difference of the signals?

Anyone have a schematic to share? I want to DIY one.

thanks

Jeff

[dynaco_dan]

Hi there;

I see them on ebay once in a while.

They have been selling for around the $35.00 range.

For one in fairly mint condition, well worth the money.

A special 3 position switch and multi-section wire-wound pot along with wire-wound resistors compose the Quadapter.

With the special case and terminal connections on the rear, I feel it would be better to pickup up one rather than attempt to assemble one from scratch.

There is also a later Mark II, not from the original Dynaco and not quite as good in it's effect, and a few copycats, licenced by Dynaco.

The simple resistor only circuit was in numerous magazine articles.

Adding a simple wire-wound resistor and re-wiring the front and rear speakers created a psuedo 4-channel/4-dimensional setup.

I have an original Dynaco record done in Dyna-Quad.

A little extra ambience at a live peformance, a train passing, just a couple of samples.

There was small list of records that contained hidden information which this sytem seemed to bring out.

I am certain that the overall enhancement, will add to any stereo system with or without special recordings.

Dynaco designed it for use with 8 ohm speakers front and rear but, AR-3a's front and AR-4X's rear would be a might fine combination, in my opinion.

Another option might be, Larger Advents rear and Smaller Advents front channel or visa versa.

Good luck.

[Guest spgjmf]

thanks vern

I think you are right...for $35 , might as well buy and

enjoy the "real" one. I'll keep my eye open ( there is one ebay now)

thanks,

Jeff

[dynaco_dan]

>thanks vern

>

>I think you are right...for $35 , might as well buy and

>enjoy the "real" one. I'll keep my eye open ( there

>is one ebay now)

>

>thanks,

>Jeff

Hi Jeff;

Just to add to my earlier thoughts.

I read somewhere that Dynaco licenced the patent use to other manufacturers, I don't know whom, other than the following.

A later, Dynaco MK II, which I believe was 5 channel.

Lafayette, I believe, used a similar one with a single pot adjustment, but with a gearing internal setup with multiple pots which were adjusted at the same time.

One or both used phono connections, rather than screw post connections.

The only slight criticism of the Dynaco I would have, in particular is, with the brass screw posts used, there is not a lot of clearance between connections.

If you use caution, you should not have any problem now, with this knowledge.

Only one strand of wire shorting out will cause you a slight headache.

The weight of the unit is only ounces and the large cables tend to tip the case upward.

If one was adept at machining, you can buy thread savers or threaded brass couplings, the same threads as the Quadapter, drill out one end only to accept a banana plug, use a brass machine screw, less head, with a lockwasher and now you have less of a chance of a short.

This isn't absolutely necessary though, just a thought I have had.

Remember that when the Quadapter circuit was invented, it was used with LP records, the result with cd's may or may not be the same, used a directed, you will still have a smile factor.

The 3 position switch, I believe, is still available from Electro Switch, not that you need to worry about it.

It is spring loaded in the up position, for balance check, normally centered, with down being a fixed position for front speakers only.

You can revert to just stereo, at the flip of a switch only.

Good luck on ebay, Jeff.

[dynaco_dan]

I see that it just went for $41.00.

It still can't be built for that price.

[Guest Eunomians]

I will be doing a review once I get the time to set up the Quadaptor. I, too, am found normally roaming the halls of the AR forum... I'm thinking of trying the Quadaptor with A25s and A10s along with my primary set up of AR3a+AR4x.

Stay tuned.

[dynaco_dan]

Hi there;

The A-25's and the A-10's are about as perfect a match as you can have for the Quadapter.

Both 8 ohms.

I only have 1/2 of an A-10, so I am not going to be having that combination any time soon.

Try to fuse your investment.

The A-10's are a little too pricey now.

Good luck with your trials.

[dynaco_dan]

>Hi there;

>

>The A-25's and the A-10's are about as perfect a match as you

>can have for the Quadapter.

>

Try to fuse your investments.

Hi again;

After looking at my old notes today, I will be adding more interesting ramblings here, real soon.

[dynaco_dan]

A quicky;

You can use 4, 8 or 16 ohm matched speakers for the front, but the rears should be 8 ohms matching speakers.

More to come.

[Guest Eunomians]

Right now I've got AR3a in front and Minimus 7 rear. It is a wonderful sounding match.

I will try AR4x rear at some point soon.

And I will try AR7 rear as well (once they arrive at my doorstep).

As I have previously mentioned, I will post my observations once I conduct my tests.

-Cheers

[ToastedAlmond]

4 of the exact same speaker is as good as it gets with the Quadaptor.

[dynaco_dan]

Hi George;

Dynaco recommended similar sounding speakers to match sound the best.

If the speaker is of one manufacturer, they usually sound similar.

Obviously 2 pair of, Dynaco 8 ohm speakers, was their intended ideal system.

Two pair of AR-4 series or AR-7's speakers would be very nice and satisfying.

A slightly improved upward match, might be, a pair of AR-4 series or AR-7's speakers in the rear channel.

AR-6's, AR-2 series or AR-5's or AR-3 series in the front channel.

My thought is, the slightly improved bass as the models are stepped upward.

With the clarity of the AR-4 series or AR-7's, being sufficiently adequate, in the rear channel.

[Guest ARStan]

I realize this is an old thread, but one of the posts asked if anyone knew of a manufacturer who licensed the Dyanco Quadaptor circuit. I have a Sherwood S-7900A reciever (same as S-8900A but with both AM and FM tuner) and this unit has the Dynaquad circuit built in. You can switch it in or out with a back panel switch. The receiver had two sets of speaker outputs, and with Dynaquad operating, the normally remote speaker terminals provided the rear channel. I used to use it with my AR-3As up front and a pair of AR-6s in the back. I was not too satisfied with it - I think the effect would have been better with AR-6s all the way around. I remember looking at the schematic, and the Dynaquad portion looked incredibly simple - just a couple of resistors between the left and right channels if I recall correctly. I think the idea was to mix both in phase and out-of-phase info between the speakers. I remember trying to hook up a speaker between the left and right "+" terminals (the transistor outputs, not the common grounds) to get just the out of phase info only. I remember that this was an interesting effect, but not enough to justify the extra hardware taking up space in my room.

Anyway, you can find these Sherwood receivers on eBay now and then for a dirt cheap price, probably less than the Quadaptor. They didn't sound too bad, were well built, and the FM section was great.

I still have that Sherwood somewhere in my basement - and come to think of it, I have the AR-6s too. Maybe I'll have to pick up another pair of 6s and try this out again..... Hmm...

[ToastedAlmond]

I had a KLH Model 52A receiver that employed it as well. I also think many Realistic and MCS model receivers also employed it. I would venture a good many more companies also.

As far as stand-alone clones of the actual Quadaptor, I have seen Radio Shacks, Archers, Lafayettes, and a Sheraton. All the knock-offs feature RCA speaker type connectors rather than just terminal posts. In fact, the Sheraton was an EXACT knock-off of the Quadaptor, except for these speaker connectors. It was packaged in the exact same box as the Quadaptor, and even had the "NULL" switch.

The newer Quadaptor II from Panor has those plastic compression spring type speaker connections, and the largest wire accepted will be around 16 gauge. I really didn't notice much if any difference in performance between Quadaptor II from Panor, and the original from Dynaco.

[soundminded]

I had a KLH Model 52A receiver that employed it as well. I also think many Realistic and MCS model receivers also employed it. I would venture a good many more companies also.

As far as stand-alone clones of the actual Quadaptor, I have seen Radio Shacks, Archers, Lafayettes, and a Sheraton. All the knock-offs feature RCA speaker type connectors rather than just terminal posts. In fact, the Sheraton was an EXACT knock-off of the Quadaptor, except for these speaker connectors. It was packaged in the exact same box as the Quadaptor, and even had the "NULL" switch.

The newer Quadaptor II from Panor has those plastic compression spring type speaker connections, and the largest wire accepted will be around 16 gauge. I really didn't notice much if any difference in performance between Quadaptor II from Panor, and the original from Dynaco.

The Quadaptor circuit could hardly be simpler to build. Just wire the hot terminals of a pair of speakers to the hot speaker terminals of the amplifier and wire the negative terminals of the speakers together without connecting them to the amplifier speaker ground or negative. That's it. I don't know how the volume control is wired, for all I know it is a variable audio taper pot in series with the speakers, say about 25 to 50 ohms. This was a simple next step after an article in Stereo Review magazine around 1962 or 1963 where they suggested wiring one speaker between the two hot terminals and placing it behind you. The speakers play the out of phase component between the stereo signals. This component was felt to contain "ambient" information. Virtually all of the matrix quadraphonic systems relied on a variant of this principle with different parameters details which were handled at the preamp signal level, not the speaker output level. The exceptions were non matrix systems, the RCA CD-4 discrete system which used frequency shifting to an outband signal above 20 khz for the rear channels on phonograph records and four channel tape recordings. None of the systems worked well and were abandoned by the late 1970s as a technical and commercial flop. From what I can tell, HT is a lineal descendant of this idea but nobody claims that it will give concert hall realism the way claims were made for quadraphonic sound in the 1970s.

[dynaco_dan]

Hi there

To keep on topic, try.

http://www.tubes4hifi.com

or

http://www.the-planet.org/dynaco

Both sites have free Dynaco manuals.

[Mark Korda]

Hi Jeff,I just joined up.I'm a Dynaco nut.I have owned all the loudspeaker line.I only got rid of different loudspeaker types(Dyna) because of the need of money.My A-35's are with Izzy,high school football.My A-50's with Gary,guard.My brother has my A-30XL's.My prize A-25 Mark2's with Gene,a football player on the opposing team.My A-40XL's with the center,Fudge.This forum was made for me.Jeff I have the manual for the original quadapter,it's small,but about 30 pages of info.Send me your address and I'll make a copy for you.There is a lot of info written down there....I loved mine when I had it hooked up.It was pre 5 channel sound and I remember Preditor with Arnold was one memory I had.There was a small rapping sound on the left rear speaker.I went to take a look and discovered my little old mom making a surprise visit with a meatloaf she cooked,not the fault of the speaker.The smoke that billowed out of my door was not from cigarettes,I don't smoke em.I'll leave it at that,bagged....Mark Korda...I'd be glad to make you a copy of the Quadapter manual.

[craig]

interesting, i think pink floyd refused to attention the opening of one of their events because it was not in quadraphonic sound. forget the event though, my friend told me about it

[dynaco_dan]

...I'd be glad to make you a copy of the Quadapter manual.

Hi there

Would you please scan and post it here.

[dynaco_dan]

Hi there

Would you please scan and post it here.

Hi there

In case I missed this comment for those that may wish to still build a Quadaptor from scratch.

The 3 section pot can be substituted with 3 equal new Ohmite pots nested with their stacking kits.

The 3 position switch was made by Electroswitch and may have been an OEM version of a model that they made back then.

My last look at their catalog showed a similar function switch but I wasn't able to confirm the exact contacts.

If the above parts can be obtained today you are likely looking at well over $100.00 to build.

It would work and the new pots are much heavier than the originals.

Perhaps there is an Asian equivalent to the pots available.

A $40.00 Quadaptor off ebuy looks pretty good to me.

Soon, when I've caught up with my housekeeping, I will post photos of the 4 different type units I have here.

Three different Dynaco and a Lafayette.

[Mark Korda]

Hi Dynaco Dan,I used to have a scanner,but I just have a printer now with my computer.I'd be glad to make you a copy of the Quadapter manual.I would need your mailing address.I would have replied earlier but just learned you have to sign in first to reply to a site.....Mark Korda

[dynaco_dan]

Hi Dynaco Dan,I used to have a scanner,but I just have a printer now with my computer.I'd be glad to make you a copy of the Quadapter manual.I would need your mailing address.I would have replied earlier but just learned you have to sign in first to reply to a site.....Mark Korda

Hi Mark

Thank you but I was suggesting that you post the pages here rather than mail them out.

That way everyone can see and enjoy them.

Thank you again, Vern