721 Woes

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Legrace
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721 Woes

Post by Legrace » 24 Oct 2019 23:39

My 721 has started acting up again. Couple nights ago I'm thinking it sounds odd. Look at the strobe and its like a Hula dancer, back and forth in a rhythmic cycle. Tonight same thing, can hear it speeding up and slowing down. The restoration money I invested obviously was not well spent. I'm done with Dual.

vinyl master
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Re: 721 Woes

Post by vinyl master » 25 Oct 2019 02:49

Hmmm...Odd, but some people actually like their Duals, esp. the 721, if this recent thread is any proof... :-k

viewtopic.php?f=37&t=114503

Tinkaroo
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Re: 721 Woes

Post by Tinkaroo » 25 Oct 2019 10:34

I'm sorry about your issue with your 721.

My suggestion would be to try cleaning the speed pot and 33-45 switch in case its some oxidation causing the issue.

I've never had my 721 professionally serviced since I didn't have it back then, but I had my 604 and 621 professionally serviced about 9 years ago and from my experience it was money well spent. I wasn't a member of this site back then so had no service experience. Klaus has been a big help to many of us over the years and we all miss his input here, but his contributions are still here in print and on his website to help us if we need them.

Unfortunately the 721 and even older models are now 40+ years old now and may need a bit of TLC occasionally. The same can be said about anything mechanical or electrical of that vintage such as a turntable or even a reel to reel.

Good luck with your 721 if you decide to fix your issue.

DSJR
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Re: 721 Woes

Post by DSJR » 25 Oct 2019 10:34

The thing is as said above while I was typing this reply, the 721 is forty plus years old (my 701 is pushing 50) and although the mechanics are probably fine still, the electronics may well be getting tired, especially regarding dry solder joints, which I hope is all that's 'wrong.'

How long should a 'domestic appliance' such as a HiFi turntable reliably last? I suspect ten to maybe fifteen years is the estimate so forty odd is good going - yes I know that 1019's are fifty odd years old now and very much loved by all who own them including me, but they seriously don't perform as well as a 700 series model. For conventional simple decks used often in the past and sourced in the far east, main and motor bearing wear can be the killer after twenty years or so but that doesn't apply to these 700 Duals in my estimation (I took a sneaky peak at my 701 bearing tip and thrust plate and under the grease, there was absolutely no wear whatsoever that I could see)

Don't give up just yet. Go over the main board PLUS the external speed pots and switch contacts. May be just enough to get it running properly again.

Do please be warned that a suitable new upgrade (sonically) will probably cost you thousands, especially with a suitable (Rega based as minimum?) tonearm for the rather wonderful array of high end pickups you use! I'm suggesting (from a UK perspective) a Rega 8 for the double belt drive, excellent bearing (-80db+ rumble) and world class tonearm.

Tinkaroo
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Re: 721 Woes

Post by Tinkaroo » 25 Oct 2019 11:41

The Rega looks like a nice turntable but retails for about $4000 before taxes in Canada.

I don't know how much the OP has invested in his 721, but surely the costs to fix the current issue are nowhere near $4600 with taxes in and the 721 is a great turntable when working properly. I've got about $150 Canadian invested in mine, again a great bargain.

I've also got a 701 too like DSJR has, also a great turntable and the father of the direct drives for Dual.

DSJR
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Re: 721 Woes

Post by DSJR » 25 Oct 2019 12:56

I forget the huge price hikes getting UK goods sold over the Atlantic and corresponding hikes with US/Canadian goods sold over here.. The Planar 8 is around £2k in the UK, which is roughly where the 721 would be, with or without a cartridge I reckon.

Maybe I should have suggested one of the new Technics '1200' models instead, which now offer a 721/701/EDS1000 style direct drive system and possibly better price in the US than a Rega 6 or 8?

It's my sincere hope that this 721 drive can be sorted as, even if the OP decides to sell it on and update (if not upgrade), somebody else could enjoy what it offers for a good few years yet.


P.S. Some weeks ago, I (and my 'kind') was roundly criticised by a UK speaker manufacturer for being so 'emotionally connected' to favourite audio gear which was designed as a soul-less 'appliance' for doing the job it was made for. That person faced with a malfunctioning deck 44 years old and very difficult if not impossible parts availability, would probably sling it to the domestic recycling centre. I think that would be a terrible shame as I bet a large number of 1219/29/49 decks have suffered this fate and all for a dearing ring plus related parts.

Legrace
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Re: 721 Woes

Post by Legrace » 25 Oct 2019 13:36

Thanks to all for the reasoned advice and talking me down off the ledge! It is an elegant machine and likely only needing a little TLC.

Tinkaroo
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Re: 721 Woes

Post by Tinkaroo » 25 Oct 2019 13:46

DSJR wrote:
25 Oct 2019 12:56
I forget the huge price hikes getting UK goods sold over the Atlantic and corresponding hikes with US/Canadian goods sold over here.. The Planar 8 is around £2k in the UK, which is roughly where the 721 would be, with or without a cartridge I reckon.

Maybe I should have suggested one of the new Technics '1200' models instead, which now offer a 721/701/EDS1000 style direct drive system and possibly better price in the US than a Rega 6 or 8?

It's my sincere hope that this 721 drive can be sorted as, even if the OP decides to sell it on and update (if not upgrade), somebody else could enjoy what it offers for a good few years yet.


P.S. Some weeks ago, I (and my 'kind') was roundly criticised by a UK speaker manufacturer for being so 'emotionally connected' to favourite audio gear which was designed as a soul-less 'appliance' for doing the job it was made for. That person faced with a malfunctioning deck 44 years old and very difficult if not impossible parts availability, would probably sling it to the domestic recycling centre. I think that would be a terrible shame as I bet a large number of 1219/29/49 decks have suffered this fate and all for a dearing ring plus related parts.
In reply to your PS: Somebody selling new equipment as this speaker manufacturer does has a self interest in us buying new equipment every few years, but if something is well built and can be kept in good fettle then isn't it wasteful to trash it, let alone the damage to the environment on several levels in doing so? All of my speakers are very old, some as old as my Duals but I still love them and refoam them if needed.

As far as any investments we make in audio it's an emotional investment which a soul less speaker manufacturer wouldn't be able to relate to. :lol:

Sietch31
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Re: 721 Woes

Post by Sietch31 » 25 Oct 2019 21:47

vinyl master wrote:
25 Oct 2019 02:49
Hmmm...Odd, but some people actually like their Duals, esp. the 721, if this recent thread is any proof... :-k

viewtopic.php?f=37&t=114503
Well I do like it indeed as it is "new" :mrgreen:

But the old lady has some issues and I haven't even listen to a single disc on it (since I'm waiting for a pre-amps) :lol: :lol:

I hope Legrace will solve the issue he is facing and continue enjoying his 721 !

GuidoK
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Re: 721 Woes

Post by GuidoK » 25 Oct 2019 22:33

I wonder wat service was done for your money.
Do you have a specification for that?

Probably cleaning pots and switches, and worst case replacing the electrolytic capacitors in the direct drive electronics (I think there are 6 or 7 that matter) will solve your problems.
Unless the last guy who was in there made a mess of it of course.

But it's worth saving. Imho it's the best dual ever made.

timnor
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Re: 721 Woes

Post by timnor » 06 Nov 2019 06:09

Legrace wrote:
24 Oct 2019 23:39
My 721 has started acting up again. Couple nights ago I'm thinking it sounds odd. Look at the strobe and its like a Hula dancer, back and forth in a rhythmic cycle. Tonight same thing, can hear it speeding up and slowing down. The restoration money I invested obviously was not well spent. I'm done with Dual.
What a coincidence. It was your posts that inspired me to invest in a 721 and buy a Jico sas. I'm really happy with the combo. But last night playing a Beatles album the record suddenly sped up. I stopped the deck playing. Played some more records and the problem didn't reoccur. Still this worries me. What should I do? Some replies mentioned checking and cleaning but I'm a newbie! How does one clean these elements? With what? I'm also gutted as I was so impressed with the 721.

Legrace
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Re: 721 Woes

Post by Legrace » 07 Nov 2019 18:43

Haven't got around to opening mine up yet as have been busy with another project. But should have some free time soon and will post an update. I was overly hasty with my original comments.

Tinkaroo
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Re: 721 Woes

Post by Tinkaroo » 08 Nov 2019 13:21

Legrace wrote:
07 Nov 2019 18:43
Haven't got around to opening mine up yet as have been busy with another project. But should have some free time soon and will post an update. I was overly hasty with my original comments.
I look forward to hearing your update once you've had a chance to have a look at it.

Your thread inspired me to put my own 721 back into the rotation and I've really been enjoying my listening sessions! :mrgreen:

mrow2
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Re: 721 Woes

Post by mrow2 » 08 Nov 2019 19:40

Still not clear on what you've already had serviced in it. Might give a chance for someone to suggest something. Lots of success stories here regarding reviving/servicing this unit.

Legrace
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Re: 721 Woes

Post by Legrace » 08 Nov 2019 20:23

mrow2 wrote:
08 Nov 2019 19:40
Still not clear on what you've already had serviced in it. Might give a chance for someone to suggest something. Lots of success stories here regarding reviving/servicing this unit.
Klaus did one of his comprehensive workups. This was among the issues, and one he really struggled with. I know as he told me so himself. After consulting with co-experts at the German Dual forum he was finally able to return the deck to spec. That was a couple years ago, had been working perfectly, in almost daily use. Clearly the components he replaced must still be good. Motor lubrication (again) or contact oxidation can be viewed as possible culprits, although the traces on the motor board might need attention as well. Certainly open to additional suggestions.

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