Dual 491-A-RC

[stiften]

A friend of mine has given me two NOS Dual turntables (chassis only) to play with: A Dual 491-A-RC and a 1237-A plus one cartridge holder with an Ortofon cartridge.

The 491 is a DD, the 1237 a belt drive, and I'd like to hear some opinions about these from owners, former owners or people that have been repairing them.

Are they worth working on and invest a bit of money in, building a cabinet etc - or should I use them for parts and experiments?

I saw in the service manual, that it is possible to adjust the 491 for 78 rpm instead of 45.

As I mostly play shellac records, and have years back modified a cheap and plasticky Technics DD in similar way, adding a switch, a resistor and a potentiometer, in order to keep the 45 speed available, I find the 491 to be the most interesting.

My modded Technics performs far better than I would have expected, and it has been working with shellac records for many years now without any mechanical problems.

The Dual tonearm (the same on the 1237) seems to be very light, unfortunately with the propriety cartridge changing system - but of seemingly good construction. Probably well suited for use with a range of magnetic cartridges for example the very compliant Ortofon M20E, that came with it, or a similar Shure V15 or Stanton 680. 

I imagine that using a medium to stiff moving coil cartridge would be a mistake in this context.

The chassis seems to be well built with a sturdy top plate and a good but small platter.

Being an automatic, with quite a few levers, springs and plastic parts, it has some potential issues with mechanical rattling and wear, and the electronics may also eventually fail, but it doesn't look as bad as some of the cheaper Duals I have seen.

A major but most likely easy problem to solve is, that the units were intended for use in music centres, with radio and cassette player, so there is no power supply in the 491.

Was the stand-alone version CS-491 fitted with a transformer to plug into the wall, like for example some of the Thorenses?

I will at least for testing need to find a transformer from a lamp or similar device to test it - or perhaps use my vario-transformer.

My friend got them from the estate of a long gone repairguy, that bought Duals in bulk for fitting them in his own cabinets. I got them for free, so it is okay to invest some time and a reasonable amount of money in at least the 491, I imagine.

But what do you think?

Have you any experience with this generation of Duals?

I guess they are both from the late 70's or early 80's.

[GP49]

1237 arm is suitable for high compliance only.

I have one and it worked fine with a Stanton 681EEE.

Here in the USA, quite a few 1237s have been scrapped for their SM-860 motors, which are needed to fix some far
more expensive Duals that came from the factory with the defective SM-840 motor.  Personally I don't think those
more expensive models are sufficiently better than the 1237 to make the effort and the scrapping of a perfectly
good unit worth it.  Bigger, more impressive-looking with more gadgets, admittedly yes. 

No experience with a 491-A-RC.  Never seen or heard it.  Never heard OF it, actually.

[stiften]

Thank you, Gene, you know your Duals, I understand.

To show you and other, that might be interested in helping, I have made a few snapshots of the "Dualtwins", the 491 and the 1237:



Looked upon from the top, the two turntables looks like twins. The 1237 (belt drive) in the top of the image, the 491 below.

The tonearm, deckplate and features are the same, and the look-and-feel quality of materials seems to be about the same.



If we turn them around, they look more like two completely different turntables in most respects.





Tonearms in the headshell end - identical. I only have one cartridge holder. The TK-14 seems to be the one I'm looking for, if the deck is worth working on.



The tonearms seem to be of relatively good quality and very light, showing that the vintage is from a time where tracking force below 1 gram and almost insanely high compliance was an important feature in a hi-fi pickup cartridge. Do also note the antiskating dial mentions CD4 (four channel system).



Centerspindle of the 491 platter. And some device to feel if a record is put upon the platter?



Centerspindle of the 1237 - a stacker spindle (which?) can be mounted insted of the short one.



The 491 seems to need a wall-transformer?



The information on the 1237 indicates that it runs on a more solid diet.



The 491 motor.



The 1237 motor (sorry I didn't get the focus quite right, but it is at least possible to identify the motor).

This is what I have. I have downloaded what I could find of manuals and service manuals, but there is very little information on these late 1970's Dual models, that are somewhat different from what I have used in my career as a music lover (for the moment Technics, Fons, Thorens and Garrard turntables).

A German site indicates that the Duals are not at all bad, but the information is old, and I don't have a clue about which reference this statement is measured against.

On YouTube I have found this, that indicates that the 491 model can be programmed for remote control (originally the RC-model was intended for systems with amp, radio etc):

Another video suggest, that the turntable (like the Beogram 1000 actually) can be used at various angles:

The 1237 seems to be more common.

There is quite a few amateur videos showing how to start and stop the device and use it with a stacker spindle, but none of the videos are showing the machine room, so if anyone will help with information about the twins, their virtues and their flaws, I'd be glad to hear from you.

My only reference to the quality of Duals are two old 1019 machines that are to be restored at some point (here I also only have one cartridge holder - and one motor seems to be shot, but I have yet to get the time to open the machine and look for a possibly burnt out capacitor). I have them mostly as a decoration in my main listening room where I keep a lot of old turntables from before WWII and up to the Beograms with tangential tonearms.

All the best and have a nice weekend.

[Lynnot]

http://www.dual-vinylfreund.de/eds-500-warten-2.html

Hi,

that EDS-500 originates from the DUAL CS 604. That is a decent quality DD turntable.
You may want to get it out of that record changer chassis, and build a Kaneda style plinth for it.

That would then also allow for one or two more flexible tonearms.

Best regards, Tony

[stiften]

Thank you for the useful link, Tony!

Kaneda plinth - like this one?

http://www.oocities.org/de/bc1a69/kaneta_eng.html

Hm... interesting, although my initial interest in the 491 was the 78 option and auto shut-off feature that comes in handy when playing 78s.

In the other hand is the tonearm only suited for very compliant cartridges like the Ortofon M20E, so I imagine your idea is quite interesting!

[wega]

Dear Hans Henrik,

from my oppinion both decks are worth to be revived. The combination of these arms and decks work well and they "sing". (Well, I have to guess for the 491, but the 1237 definately does!) .
 The "A" behind the numbers indicate that these turntables were equipped with S-shaped arms as OEM equipment for musiccenter manufactures ( like Wega, Saba, Nordmende, Liesenkötter, just to name a few. Grundig always got branded (non-)slipmats). Dual-branded standalone Turntables never used S-shaped arms, always straight.
As you already said, the 1237 is a changer. The stacker spindle you would need is called "AW3" (Abwurfsäule). Look at www.pollin.de , they sell some old surplus arround 8 EUR.
To get the automatic working, you most probably will have to replace the "Steuerpimpel" (sorry even in german this word sounds made up!). It is a kind of friction clutch. It is operated by the big black lever. Under the flat end of it, close to the tonearmbase, there should be a little "pin" with a rubber/plastic cap on it. This cap des-integrates over time, leaving crumbly or greasy remains.
Remove the Black leaver, clean the flat end with alcohol (it's a wast, I know ) and replace the rubber cap with 5mm cable isolation or shrink sleve. google for pictures using "Steuerpimpel" as the search term.
When done, lock the arm on its rest and activate the autmatic "play". This will re-calibrate the automatic.

Hope this helps,
Regards,
Stefan

[stiften]

Dear Hans Henrik,

from my oppinion both decks are worth to be revived. The combination of these arms and decks work well and they "sing". (Well, I have to guess for the 491, but the 1237 definately does!) .

Hope this helps,
Regards,
Stefan

Dear Stefan.

Thank you for your kind help.

I will try to clean and test the 1237 to get a picture of how much work there is in the revival process.

One of my problems is, that I have no idea of what to compare them with. I have not seriously listened to a Dual since the 1229 model was new.

Many of the more recent Duals have - to my eye - looked pretty flimsy and fragile compared to the 1019 I have in my little "museum".

The 1237 and the 491 seems to be better built, than the last one I saw at a friend, bought new a few years ago.

But does it sing in the same way as a Project Debut, a Rega P3 - or my old trusty Fons, that also has a light tonearm and sports a belt in the drivetrain:



Best wishes from Henrik.

[wega]

Hi Henrik,

in fact I had once the chance to compare a Pro-ject Debut (II?), a Dual 1254 and a 1237 (straight arm). I have to admit that this was not under scientific correct conditions. They had to sit on a shelf, not wall mounted. The cartridges were "similar" but not same (AT95E and Dual DN 242). Some wine was involved as well...
The Dual 1254 came in last. An insult to ears and hand. The pro-ject was ok but in a way a bit - boring?That might be related to the "board on a board" situation. I liked the 1237 best. Although it moves a lot auf automatic jumble inside and has the iritating small 25cm platter.
Another thing to me is that I begin to like at least stop-automatic. In case i wander off, the stylus is not riding  the end groove for hours...
If you dont have a plinth, a test on tins already gives a good impression. (Do lentils sound diffrent than tomatoes?).

PS: My main tables are Lenco L78 with CEC SME-arm, Lenco L85, Wega JPS 350 and Dual 1247

Have fun, Stefan

[Lynnot]

Hi,

1019, 1219 and 1229 are the good ones. Appart from rumble levels, all belt drive and direct dive Duals sound worse.
(well, with possible exeption of the 701, I never heard one) This may be caused by the lighter platters of the newer players.

Rgds, Tony

[stiften]

Hi,

1019, 1219 and 1229 are the good ones. Appart from rumble levels, all belt drive and direct dive Duals sound worse.
(well, with possible exeption of the 701, I never heard one) This may be caused by the lighter platters of the newer players.

Rgds, Tony

Perhaps it is possible to add some weight to the 27 cm platter - or stack another on top - if I choose to use the 491 for a project with heavy plinth and different tonearm(s).

Edited later: For the moment I have located a cheap and almost fully functional 1209 with no cartridge and no counterbalance - but a cartridge holder. And the battered plinth seems to fit the 1237 and the 491.

I imagine this cartridge holder will fit the stock 1237/491 tonearms in order to make a short comparison with what I have already.

The next days I will look in my drawers and the thrift shops for a power supply to feed the 491 and some other parts I need for setting up a testdrive.

Thank you for good ideas and viewpoints from all of you.

[GP49]

For the moment I have located a cheap 1209 with no cartridge - but a cartridge holder.

I imagine this will fit the stock 1237/491 tonearms in order to make a short comparison with what I have already.

Yes.  Some early ones have deeper sides but they all fit (the design was modified to save a gram or so of mass and a pfennig or so of plastic).  Also the earlier ones have brass leaf contacts, newer have spring-loaded pins.

[stiften]

Yes.  Some early ones have deeper sides but they all fit (the design was modified to save a gram or so of mass and a pfennig or so of plastic).  Also the earlier ones have brass leaf contacts, newer have spring-liaded pins.

Yes, I can see, that the old one have leaf springs, but it fits the 1237/491 tonearm - but not the arm on my two 1019 machines.

For the 1019s I still only have one cartridge holder with a Shure cartridge - and have not recently seen any machines in such a bad shape, that I wanted to buy them just for this part.

Thank you for your help.

[Lynnot]

For the 1019:

TK 11 = standard 1/2" mount

TK 111 = TK 11 + Shure M44
TK 121 = TK 11 + B&O SP 1
TK 131 = TK 11 + Pickering V15/DAC

TK 12 = standard 1/2" + Dual clck-in

TK 151 = TK 12 + CDS 630
TK 161 = TK 12 + CDS 640
TK 168 = TK 12 + CDS 651

Good luck in searching!

[stiften]

The stacker spindle you would need is called "AW3" (Abwurfsäule). Look at www.pollin.de , they sell some old surplus arround 8 EUR.
Hope this helps,
Regards,
Stefan

Thanks. I got the spindle today (postage more expensive than the spindle, but Pollin had put two gift-vouchers in the package with a catalogue, so no big deal.

Has just briefly tested it in the 1209, and it seems to work fine, so I guess it will do the same in the 1237 when I have the time to work a bit on that. Thank you for kind help.

All the best.