Dual 721 turntable - opinions/advice?

I just picked up a Dual 721 for under $20. Seems to run fine. Looking at the strobe, it looks like it is maintaining speed. It has a "supposedly" new AT120E cartridge. Maybe new 20 years ago? Dust cover is thrashed.

I thought I might have someone put new RCA cables on it, a little oil on the bearings, and put my Sumiko Pearl cartridge on it.

• Any advice? Thoughts?
• How does this TT compare to others?
• How does this compare to my Akai AP-Q80 direct drive TT?
• Any ideas where to get a dust cover in decent condition?

I'm not sure the Sumiko is a good match for the Dual ULM arm. I would stick with the AT120E and simply replace the stylus. I just sold a Dual with that same cartridge and the combo was very good. The Dual was designed in an era where high compliance cartridges were the norm. The opposite is true today. But the Ortofon OM series, as well as Ortofon's new 2M line and the Shure M97xE, are widely available and match well.

I have no direct experience with the 721 but I've had my share of Duals from that era (and with that same basic tonearm) and my guess is that the drive system is at least equal to that of your Akai and the arm is probably far superior. You traded up, especially considering you spent only $20.

As for the dustcover: You've heard of eBay, right? That would probably be your only shot, but any dustcover that old is going to be at least somewhat worn. So you might try buffing it out with plastic polishes like those from Novus or Meguiars. If it's really bad, it can be first wet sanded, then buffed. There are people who advertise dust cover restoration service, but the cost is somewhere around $100 plus shipping both ways.

So...$20 for the table, $50 for a new stylus unit, $7 for some plastic polish and rags and a few hours worth of elbow grease. For well under $100, I'd say you have a very nice turntable that should be comparable in at least some respects to the entry-level stuff of today. Enjoy.
Actually, I paid $10.

The dustcover is cracked all the way across the middle, side to side. And I know cosmetics are not critical to function, It would be nice if it looked better.

I don't understand "high compliance" or why the brand new Sumiko wouldn't be a good fit. I'd appreciate whatever you can do to educate me on this topic of matching tone-arms with cartridges. I was worried that the Shure or AT would be too bright for me in the highs. What is a "ULM" arm?

Phono cartridges have suspensions, just as cars do. If you were to put a very stuff suspension on a very lightweight car, the ride quality would be stiff and unbearable. Conversely, if you put a very compliant suspension on a heavy car, it would be squishy and prone to bottoming out.

The same is true for phono cartridges. The Dual ULM arm is Ultra Low Mass -- very lightweight. So, you need a cartridge that has a very compliant suspension so that is can be loaded properly. A low compliance cartridge will be too stiff, and it will introduce audible resonances.

Today, most tonearms are medium to high mass, and most cartridges are accordingly designed with stiffer suspensions. The Sumiko is best matched with medium mass arms. The Dual arm will likely not have enough mass to properly load the suspension...the cartridge will just sort of ride on top of the grooves. At best, it could sound like crap. At worst, it could possibly damage your LPs. Now, you could add extra weight to the headshell...but that defeats the purpose of the ULM concept.

Therefore, it would be best to stick with one of the cartridges I recommended. If you have a cheap phono stage, the Ortofon OM10 would be an appropriate solution as would the Shure M97xE. If you have a decent phono stage, then I would recommend the Ortofon 2M Red or a new stylus for the Audio-Technica. And if you have a better-than-average phono stage, it would not be unreasonable to suggest the Ortofon 2M Blue. I'm using one now on a Dual CS-505-3 and it sounds great.

In any event, the Audio-Technica AT120E is a more resolving cartridge with a finer stylus unit than the Sumiko so regardless of compatibility issues, replacing the AT120E stylus would be the cheapest path.

As far as the dustcover....it keeps the dust off, right? It's best to remove it anyway when listening. If you leave it up, it acts as a "sail" for resonances. If you put it down, it can allow static electricity to build up. Remove the hinges and rest it on top of the table so you can easily remove it during use. If you think of it as a dustcover rather than an aesthetic part of the turntable's design, then you can buy virtually any replacement that rests comfortably on top.

I really think you made a fine buy there. The fact that your Dual is still functioning as intended 30 years later speaks to its enduring quality. Like an old car, you have to put a little bit more effort into replacing parts (in this case, the cartridge) but assuming you use properly suitable replacements, there's no reason why the Dual can't sound good even by modern standards.
Thanks, very clear information.
Since the owner claimed that it "had a new needle", how can I evaluate the condition of the stylus?

My phono stage is a Proton 1100 preamp. It likely doesn't stack up against preamps in the multi-hundred dollar range, but my understanding is that the innards are essentially identical to a NAK of the same class. So, from what I gather, not a bad little pre.

Now what to do with the Sumiko cartridge.

I misspoke. My Proton 1100 is pretty much identical to a NAD 1130.

Is there a thread here to help a newbie evaluate the condition of a stylus?

Just replace it. A new stylus is about $60 for the Audio-Technica. Cheap insurance. There is really no way -- aside from gross mistracking -- for someone without a microscope and experience to effectively evaluate the condition of a stylus. Besides, even if the stylus is fine, the suspension bits may be dried up and damaged. A new stylus unit insures against both possibilities.

Your Proton has a pretty good phono stage. Like NAD stuff, it can sound a bit 'dark.' So, provided your speakers aren't overly bright, I would go with the Audio-Technica AT120E you already have or the Ortofon 2M. Both have detailed enough treble to counteract the preamp's tendencies.
I just came across this thread. Craig your 721 does NOT have the ULM arm, it has the 4 point gimbal. It will accept a 1/2 inch cart from 4.5 to 10 grams. I have a CS-721 late model. You can tell if yours is late or early by the platter. The early only has one strobe band on the platter versus the late model with a seperate band for 33/45 and 50/60 hertz. I have an ortofon 2M blue on mine which is my primary cart but depending on what I'm listening to I'll switch to my V-15iii with a super tracker plus. Don't take this TT lightly as it is very good if its in good working condition. It was duals TOTL when it came out and it also has the EDS-1000 which, according to the "big mag audio folks" is the quietest direct drive motor made. I tried the M97xe from my DUAL 1246 on the 721 and I didn't like it but hey, thats me. I have a Nagaoka MP-150 in route from LP Gear. A bud has this cart on a 701 and he sez its all good.
This was my standard for many years. I owned a 701 then moved to the 721 back in the late 70s. It was a very quiet and reliable table. Some days i do miss that automatic function on the table.
I've has a Dual 721 for about 15 years. When I took is out of the plinth to replace the RCA cables, I couldn't help being amazed at how clean it is. This turntable had been sheltered all of it's life...a life of more than 40 years!
I'm not having any trouble with it but recently decided to upgrade the entire sound system. I started with a SCHIIT phono preamp. Schiit Vadar amp and Magnapan speakers should be here this summer but in the meantime, I bought a Fluance RT 85. It comes equipped with a Ortifon Blue cart. I was very impressed with the cart but the turntable had some sort of grounding issue on one of the channels, so I sent it back. I then decided that, being so impressed with the M2 Blue, that I would upgrade to the Ortofon Bronze and install it (with a new cartridge sled) on my Dual 721.
Here is where I am seeking advice and counsel.
Either my ears decieve me or the M2 Bronze is being muted in some way on the Dual 721. I'm wondering if, at a certain point, it is possible to hit the wall on a Dual 721 with cartridge upgrades!
If true, I wonder what aspect of the Dual 721 is driving this limitation?
Assume the tonearm to be balanced and the vertical tracking angle good, what other tweaks could translate to getting maximum benefit from this cart?
I did notice that the output of the M2Blue is 5.5 mV and the M2 Bronze is 5.0 mV, but the preamp certainly makes up the difference.
Does anyone have any thoughts?
Define “muted”.
I'll try.
Keeping in mind that at the point that I heard the 2M Blue on the Fluance RT 85, I had been used to hearing the the Dual 721 with a Vessel A3SE mounted on it. I only had the 2M Blue for a couple days but the color words chosen by Ortofon seem appropriate. The Blue was bright and precise....at first test, the acustic guitar on Beggars Banquet came out from behind the wall and even at low volume (especially at low volume) seemed to be in the room. At the next listening session I tried Strauss' Also Sprach Zarathrustra and Rimsky-Korsakov's Scharazade. The treble was sharp and the base precise. I heard individual stikes of drums instead of boom, even with the limitations of speakers that need to be replaced. When I compare specs of the Vessel with those of the 2M Blue, there is no doubt that the brilliant and precise sound I was hearing from the 2M Blue was objectively a better reproduction of sound..... The difference between the view of a landscape on a foggy morning versus a view of the same landscape under a crisp azure sky. 
After ordering a new cartridge sled and mounting the 2M Bronze on my Dual 721, I expected to appreciate another leap ahead in response. The difference was not that obvious. Of course, I was not comparing oranges with oranges. The 2M Blue was mounted on a different turntable and the 2M Bronze on my Dual 721. Did my ear acclamate to the 2M Blue after only two listening sessions? Was it more that I was expecting to objectively notice some aspect of the performance to be superior? The 2M Bronze, relative to the blue, sounds capable but not brilliant....that could be the difference of 0.5 mV in output? 
I have no doubt that the 2M Bronze was the right decision but I do hold to my original question. I wonder if the Dual 721 will supress the perceived performance of cartridges beyond a certain point and, if so, what is that limitation caused by.
I obsessed for a couple days over the stylus rake angle but after ascertaining to the best of my ability that the tonearm is parallel to the record surface and after getting photos of dynamic tracking, the rake angle alas looks fine. I have the Ortofon test record on order. 
I think the Dual is currently adjusted appropriately but if there is any problem with the azimuth, hopefully it will be identified by use of the test record.