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Re: Longevity of Technics suspension

Posted: 18 May 2019 06:09
by H. callahan
yarvelling wrote:
17 May 2019 19:57
Download the service manual from here:
https://www.vinylengine.com/library/tec ... q202.shtml

read through it, and it'll show how the top plinth and sub-chassic go together. It will also indicate where/which corner, the 'silver' spring should be. It will also show where the wires from internal boards should be routed; likewise, the power/audio connectors should be routed out of the chassis.
This way, you can check to see that your turntable hasn't been opened in the past and re-assembled incorrectly.... I know how the incorrect placement of the suspension springs can completely ruin the performance on this, and similar turntables from personal experience! Likewise with wiring...if it fouls or is trapped internally, or is routed improperly to the exit points, then it can/will foul the suspension.

Oh....and you have checked - haven't you - that there are no transit/transportation locking pegs left inplace underneath the platter....? :wink:
As my tt might suffer a similar problem, could you please point out where/in which corner these "silver" springs are supposed to be? This is taken from the service manual of the Technics SL-Q202:
Technics SL-Q202.JPG
(114.15 KiB) Downloaded 92 times

Re: Longevity of Technics suspension

Posted: 18 May 2019 10:10
by Luxman78
yarvelling wrote:
17 May 2019 19:57
Download the service manual from here:
https://www.vinylengine.com/library/tec ... q202.shtml

read through it, and it'll show how the top plinth and sub-chassic go together. It will also indicate where/which corner, the 'silver' spring should be. It will also show where the wires from internal boards should be routed; likewise, the power/audio connectors should be routed out of the chassis.
This way, you can check to see that your turntable hasn't been opened in the past and re-assembled incorrectly.... I know how the incorrect placement of the suspension springs can completely ruin the performance on this, and similar turntables from personal experience! Likewise with wiring...if it fouls or is trapped internally, or is routed improperly to the exit points, then it can/will foul the suspension.

Oh....and you have checked - haven't you - that there are no transit/transportation locking pegs left inplace underneath the platter....? :wink:
Thank you Mr. Yarvelling!

There's good news and bad news. Bad news is I must admit I'm an incompetent noob who got you good people on a wild goose chase.

The good news is it WAS the subsonic filter. The mistake I made was in thinking my pre-amp has the filter built in it, while in fact my power amp has the filter. It is a NAD combo 2700THX for the power and 106 for the control.



The power amp was out of order for some time. It had a problem which I now manged to fix, but while fixing it, I used the 106 as a sort of phono-amp because it handles TT very well, the sound is much better although the amp I connected it to has its own phono input, but it's not as half as good.

That's when the trouble started, I thought the pre-amp has the filter so I ruled that out and started looking elsewhere.

In the meantime I've fixed the power amp and while giving it a test run, I connected the TT again and did all the tests and noticed the pulsating stopped. Just to be sure I've cranked it way, waay up and still nothing. When I turned the volume even higher up to like 75% of the amp it started again, but I'd consider that to be negligible.

Also, to double check, I've plugged the pre-amp into a different set of inputs offered by the 2700 power amp for home theater. These HT inputs bypass the filters as for movie sound effects you'd want your sound to extend as far into deeps and highs as possible. This started the pulsating again. In the end it probably is acoustic feedback, but nothing that filter doesn't weed out.

This doesn't rule out the suspension completely, it's obvious that the vibrations do reach the stylus, but it's not a problem at normal listening levels.

Re: Longevity of Technics suspension

Posted: 18 May 2019 14:38
by H. callahan
Ah, that´s good news, as i was racking my brain what could be the cause of your problem. I was evolving a theory, but this could have been a long story...

Re: Longevity of Technics suspension

Posted: 18 May 2019 16:38
by lenjack
So, you think your suspension is OK? I was beginning to think acoustic feedback when you said the cones were pulsating. This type of suspension should prevent that, and the old AR di, but apparently, you pushed it beyond the limits of the Technics design.

Re: Longevity of Technics suspension

Posted: 18 May 2019 21:18
by lbls1
My unit is from circa 1990, and I am having absolutely no problems from it. Technics' quality in its manufacturing would shame some of the high dollar crafts you would see today.

Re: Longevity of Technics suspension

Posted: 18 May 2019 21:53
by Luxman78
Mine is 1981, works well for the most part. Which model from the '90 you have?

Re: Longevity of Technics suspension

Posted: 18 May 2019 22:30
by lenjack
My sl-d3 dates to 1979. I'm 2nd? owner. Has been serviced knowledgeably, except tobacco stains, which I took pains to remove. Works perfectly.

Re: Longevity of Technics suspension

Posted: 18 May 2019 22:38
by Luxman78
lenjack wrote:
18 May 2019 22:30
Has been serviced knowledgeably,
I could sure use some of that! :wink:

Re: Longevity of Technics suspension

Posted: 18 May 2019 22:47
by lenjack
I could refer you, but my guy lives in Maryland, USA :(

Re: Longevity of Technics suspension

Posted: 18 May 2019 23:37
by Luxman78
lenjack wrote:
18 May 2019 22:47
I could refer you, but my guy lives in Maryland, USA :(
Across Europe and then across the pond!? :D :D
I buy the new 1500 which I secretly fell in love with (but can't say that in front of my 202 :oops: )

Re: Longevity of Technics suspension

Posted: 18 May 2019 23:41
by lenjack
I won't tell. It doesn't look all that much different, or does it?

Re: Longevity of Technics suspension

Posted: 19 May 2019 06:49
by lbls1
Luxman78 wrote:
18 May 2019 21:53
Mine is 1981, works well for the most part. Which model from the '90 you have?
SL 1200 MK2

Re: Longevity of Technics suspension

Posted: 21 May 2019 20:14
by Luxman78
lenjack wrote:
18 May 2019 23:41
I won't tell. It doesn't look all that much different, or does it?
It's the simplicity that got me. I'm talking about the new model, of course. It's not even that far from my budget.

Don't tell me you fly your TT to US to be fixed?

Re: Longevity of Technics suspension

Posted: 22 May 2019 01:45
by lenjack
Manuals are, by their nature, simple.

Re: Longevity of Technics suspension

Posted: 25 May 2019 16:25
by Luxman78
BTW, I bought a new vinyl record for testing purposes, I wanted to exclude the possibility that my cones are vibrating due to warped record.

I wanted to say that I'm very happy with how my TT sounds. Playing a new, flat, clean record really makes the system shines. The cones are still pulsating, though. I'm starting to think it has to be the feedback (or perhaps needle detecting some subsonic rumble that I can't hear).

I'll try moving my TT around tomorrow, when I finally get some free time.

Thing is; subsonic filter does fix the problem, but I think it would be better to minimize it before even using subsonic filter. I think performance would be much better if there was no distortion to start with.