Mod: Sl1200mk2 Improving Wow And Flutter

[alfonso]

FWIW I have repeatedly measured an SL-1200 against a GyroDec.

The Technics has less wow (<4Hz).

Flutter (4..10Hz) is roughly the same on both.

But if you look at higher modulation frequencues, you see
that the Technics has a bulge from 100 to 300Hz or so,
which is totally absent on the Michell.

This is the flutter band that normally doesn't get measured on
TTs (especially not when weighted), but in a tape machine it
would coincide with scrape flutter, which is known to add
aggression to the sound.

Aha! So this is what i heard as a smoothness difference between a Lenco and the typical Technics DD.

Do you have a graph?

OneyedK, i have the same question as you, but i'm guessing that this is a motor/drive circuit issue, not a plinth or bearing-related issue.

So...you stated that under 0,06% wow and flutter are inaudible..and now you're saying that you were able to listen with you OWN EARS some flutters not visible NEITHER by looking at the strobe?! Is that possible?! Also,that a lenco l75 sounds smoother than a sl1200 has yet to be proven for what we know..tough there's no doubt that can be preferred

Alfonso, "0.06% wow and flutter" is shorthand for saying "0.06% wow and flutter considered at only certain frequencies, measured by the manufacturer and weighted using a weighting curve that may not represent the ears' real sensitivity to speed variations".

Werner's post above is clear: You can measure little wow (<4Hz), little flutter (4-10Hz) but some other things can be happening at higher frequencies, where the ear is more sensitive.

Yes,of course but all tt's are weighted at certain frequencies that not represent all the frequencies that our ears can handle! So,probably,all tt's have way more speed instability than those measured by the manufacturer! Even Lencos...and thorens.Of course the michell is in another level cause is way more expensive. Anyway everybody's happy with sl1200 speed stability wich is considered to be outstanding in that price range..even those who can stand how it sounds appreciate its accuracy! So we can't all be deaf! Lenco's l75/78 have never been more accurate in terms of speed stability than a technics sl1200/sp25...that doesn't mean they can't sound as good...and if you think about it,if what you say was true,then means that everybody has believed with their minds and ears something totally wrong in the last 40 years!!! Is that possible?! And i obviously consider lencos l75/78 as great sounding decks

[shhh...listen]

http://www.vinylengine.com/phpBB2/viewtopic.php?p=292419#292419

[alfonso]

http://www.vinylengine.com/phpBB2/viewtopic.php?p=292419#292419

Hi
this article has been already discussed in a lot of forums and by reading those discussions you'll see how hated it has been .It has to be one of the more useless articles ever wrote and,what is even worst is that is based on totally wrong assumptions,like the fact that dd's are constantly in search of the right speed,that inside the sl1200 the board is generating jitter (wich is impossible as that turntable is fully analog). I strongly suggest,instead,to read the excellent review of the sl12oo wrote by Werner himself who,in the introduction of that review,dismantles all the false myths about direct drive tt's and all those about the belt drive supremacy.You can also search in the kab website,where all these false myths have been dismantled aswell.

[cafe latte]

http://www.vinylengine.com/phpBB2/viewtopic.php?p=292419#292419

Hi
this article has been already discussed in a lot of forums and by reading those discussions you'll see how hated it has been .It has to be one of the more useless articles ever wrote and,what is even worst is that is based on totally wrong assumptions,like the fact that dd's are constantly in search of the right speed,that inside the sl1200 the board is generating jitter (wich is impossible as that turntable is fully analog). I strongly suggest,instead,to read the excellent review of the sl12oo wrote by Werner himself who,in the introduction of that review,dismantles all the false myths about direct drive tt's and all those about the belt drive supremacy.You can also search in the kab website,where all these false myths have been dismantled aswell.

I come in in the evening and enjoy my TT. I dont really care what others think of it, If you enjoy it as I do that is what is important
CL

[Eoin]

I come in in the evening and enjoy my TT. I dont really care what others think of it, If you enjoy it as I do that is what is important
CL

Me too! My turntable's probably a heap of junk compared to some, but I love it.

Now playing "Have a Cigar" by Pink Floyd through my new amp. Cheers!

[alfonso]

http://www.vinylengine.com/phpBB2/viewtopic.php?p=292419#292419

Hi
this article has been already discussed in a lot of forums and by reading those discussions you'll see how hated it has been .It has to be one of the more useless articles ever wrote and,what is even worst is that is based on totally wrong assumptions,like the fact that dd's are constantly in search of the right speed,that inside the sl1200 the board is generating jitter (wich is impossible as that turntable is fully analog). I strongly suggest,instead,to read the excellent review of the sl12oo wrote by Werner himself who,in the introduction of that review,dismantles all the false myths about direct drive tt's and all those about the belt drive supremacy.You can also search in the kab website,where all these false myths have been dismantled aswell.

I come in in the evening and enjoy my TT. I dont really care what others think of it, If you enjoy it as I do that is what is important
CL

Hi cafe
you're right...but at least let's try to spread some knowledge! I mean...just for the fun of it
Of course...spinning vinyls is even more funny

[alfonso]

I come in in the evening and enjoy my TT. I dont really care what others think of it, If you enjoy it as I do that is what is important
CL

Me too! My turntable's probably a heap of junk compared to some, but I love it.

Now playing "Have a Cigar" by Pink Floyd through my new amp. Cheers!

Wow...Pink Floyd + Roy Harper's vocals...now that's how to enjoy a record player!

[thegr8brian]

I own a SL-1200M3D and I do indeed have the 220nf in there. I plan on getting my hands on a 330nf cap this weekend and I'm gonna try this mod out. Has anyone other than OneyedK tried this out?

[martinwtaylor]

IMO, mats that are not glued to the platter don´t help no matter what mats.

Agreed, I've experimented with a few mats and settled on an Achromat on the Mike New platter on my 1210. The trick to getting this combination to sound excellent is to use a thin layer of petroleum jelly to bond the mat to the platter. This gives good damping and coupling characteristics and sounds tonally neutral without the dark Technics sound being at all evident.

[shhh...listen]

The motor of the 1200 has poles that do not overlap.

That's something that is misunderstood.
The motor itself has indeed poles that do not overlap.
But, the three phase driver takes care of that, those phases do overlap. And there is no cogging...
That's one of the reasons why DJ's like the deck so much, you can slow it down by hand and it will go back to speed smoothly.

This is worth reading
http://www.answers.com/topic/wow-and-fl ... easurement

Thanks for the link!

Can you elaborate a bit on the basic operation of the motor. Attached is illustration I made in trying to understand what is going on with the motor, but it didn't help.

Technics motor with representation of 16 pole ring magnet superimposed. Green segments are where poles align with coil and plus sign is the next pole in sequence to align.

[album]17889[/album]

[OneyedK]

Can you elaborate a bit on the basic operation of the motor.

Very difficult without using hands and feet. English is not my native tongue.

If there were 12 "magnets" and 12 coils, this would become a 3 phase 3 coil motor. Still not much cogging, since the three phase driving circuit uses overlapping sinewaves (as a normal 3 phase motor, used in the best idler drives in the world).

Now there are 16 "magnets" and 12 coils. The coils driven in 3 phases, overlapping. But, there is a 12/16 reduction in efficiëncy.
This trick makes sure that only one polepiece at a time is 100% aligned with a coil. Not 4 as in the 12/12 example.
So if you make a new drawing, draw lines between the North and South of the polepieces.

Hope this clarifies things.

For me it's time to set the Technics aside and to start working on my Thorens machines. I couldn't find an improvement over the 220nF//330nF mod (yet), maybe I restart later...