Need some quick Technics help

[fletchdirect]

Hi All,

I am now embarking on a modification project for one of my Technics 1200s and clearly this is the best place online to get some knowledge from!!
I basically need to know 3 main things to help me:

a) It seems that the mods are arm/psu/mat/feet/bearing. What is the correct ranking of upgrades in order of % difference. So if 100% is a huge difference, does the arm make up 60% of that, and then PSU 30%, mat 5% etc etc. I just want to ensure that I invest in the right areas. Cartridge budget is about £500.

b) Based on the above, how do you apportion a budget? I am not really sure what to budget yet. I am sure that an SME V would reveal the differences in more expensive feet than a Jelco or Rega arm. I am just getting a feel for where to invest most - e.g. cheaper arm will do, but don't skimp on the PSU.

c) Are there any particular standout products or arm and cart combos to note, that have really worked well?

I know that a lot of info exists on the Techiepedia and I am sure that there was a thread to answer point (a), but can't find it.

System is Kenwood L-1000C+M, Trichord phono stages, Yamaha NS1000, Scanspeak and Vita homemade speakers.

BIG THANKS!

Cheers
Julian

[Macca]

Any veteran Techie modders out there who can assist with this?

[Stratmangler]

Here's a good place to start http://theartofsound.net/forum/showthread.php?26620-SL-1200-DC-Power-Supply-DIY

[fletchdirect]

can no-one help me?

I know that there is a huge amount of posts and info regarding the Technics mods in this forum, but I just wanted a quick guide as to where to start first and what will make the most difference.

Please help!!

Thanks

[CageyH]

Get the power supply out of the deck, either by DIY methods or fitting an external PSU. This will help reduce noise in the cartridge. The next big hitters in my experience are the arm and cartridge.
Everything else after that just builds on the solid foundation given by a good arm/cartridge combination.
The bearing will make a big difference if you have a worn bearing, but subtle if your bearing is in good condition.
A set of decent feet help open up the sound, and platter mats make subtle changes.
Then we are into platter upgrade territory, depending which route you decide to go, this could be as simple as an SDS isomat to a MN ETP or Funk Strata.

[Wakefield Turntables]

This is my 5 year adventure into 1210 modification.

http://theartofsound.net/forum/showthread.php?9568-Me-and-the-1210-are-gunna-have-us-some-me-time

Just about every weird and wonderful idea has been tried. I run a SME V so you might get some help with this thread.

The adventures still continue as I may try the new Bo!ng feet which are supposed to be better than my Isonoes.

Enjoy.

[Mike_New]

Hi Julian,
I have to be careful of the advice I offer as I could be accused of being horribly biased.
This is the path that a great number of people have followed.

a) Replace the internal power supply with an external unit, There are a number to choose from but the KAB unit is probably the economical choice and easy to fit and wire up. You could then graduate to the Paul Heynes multi voltage unit at a
later date.

b) Fit a replacement bearing in order to reduce harmonics and noise generated by a far less than perfect bearing design currently fitted to the SL1200.
For the ultimate choice you would be considering my High Precision Bearing. The housing of which is machined from a solid bar of brass and the shaft hand fitted to a precision honed sintered and oil impregnated bearing insert.

c) This could then be followed up by the fitting of my Bearing Base Plate which is a 6mm thick steel plate which is
bonded to the bottom of the Chassis. The Bearing is then bolted to this using three strong tensile bolts threaded into the steel plate, allowing a very rigid connection.

d) And then if funds permit you could fit the ETP Platter which is reckoned to give great results.

However I do recommend that you look at replacing the power supply as your first step.
After attending to the electrical and mechanical updates you would then be in a position to take full advantage of the improved sonic resolution of any Tone Arm you may choose.

[jostber]

I agree with Mike that the bearing is a significant upgrade and will give a better sound all over. Recommended. If you want to start off easily with not too much work, I would suggest to invest in a quality cartridge, change the rubber mat to a more audiophile one, and change the feet to something like the Isonoe feet. These changes will quickly give you great synergy effects, and you can enjoy your deck until later more advanced upgrades if you want that.

[Stratmangler]

can no-one help me?

I know that there is a huge amount of posts and info regarding the Technics mods in this forum, but I just wanted a quick guide as to where to start first and what will make the most difference.

Please help!!

Thanks

See my post #3 in the thread.
Just getting the PSU out from under the platter and into a separate external box - this is covered in post #1 of the thread I linked to, and in that post there's a link to another thread. Follow the links.

While you're under the bonnet take the bearing out and pop an O ring in the bottom of the bearing well. This will damp a lot of the bearing vibration.

[dmckean]

I agree with everyone else, get the vibrating transformer out of the deck first.

Even though arms and cartridges can make a big difference in sound, it's always best to take care of the deck first. If you do all the table upgrades, when you eventually do upgrade the arm, even an inexpensive cartridge will sound fantastic.

[Marco]

Yup... Great advice there, Dave :thumbsup:

Marco.

[Khom]

I did some measurements a few years ago, see picture. Checked hum when cartridge is over vinyl and on it, inner and outer groove. I was surprised by the second harmonic (100 Hz) and tried to lower it by removing upper part of transformer permalloy shield, but no luck. Obviously, it's mechanical hum. So, moving transformer into separate case is absolutely necessary action.
http://i1159.photobucket.com/albums/p625/USSR_Rik/613d2ab6-6243-4cf3-91a5-d5c0f0c0a8ad_zpssptcsqqg.png

[Mike_New]

Interesting traces Valery, I like coloured wiggles!!
I notice that the "power ON in outer groove trace at 100Hz, which is further from the transformer; is somewhat higher than the
"power ON" inner groove which would be much closer to the transformer.
At 50Hz they are identical but slightly higher in amplitude. How would you explain this??
One possible analysis is that the platter is vibrating at the second harmonic due to bearing looseness allowing it to do so.
The outer edge of the platter would of course have a higher amplitude than the inner part.
What would happen if you put a heavy weight onto the centre??

[Khom]

Sorry for delay. I don't have suitable explanation for the same levels at 50 Hz. I can suspect only interference between waves coming through two ways for transformer vibration propagation. First: base -> main bearing -> spindle -> platter -> needle and second: base -> tonearm pivot -> tonearm tube -> cartridge. I'm not sure. Besides, it was a quick test and I could be wrong.

100 Hz can be explained by transformer coil vibration, because we have bridge rectifier and current consumption has the form of short and high amplitude currect pulses at 100 Hz. Additionally, it can be magnetostriction effects or transformer shield vibration.

When I got Techie I knew that transformer must be removed in short time and I didn't make detailed experiments. I just removed it and forgot.

[guardofmagog]

I did some measurements a few years ago, see picture. Checked hum when cartridge is over vinyl and on it, inner and outer groove. I was surprised by the second harmonic (100 Hz) and tried to lower it by removing upper part of transformer permalloy shield, but no luck. Obviously, it's mechanical hum. So, moving transformer into separate case is absolutely necessary action.
http://i1159.photobucket.com/albums/p625/USSR_Rik/613d2ab6-6243-4cf3-91a5-d5c0f0c0a8ad_zpssptcsqqg.png

Back in 2009 there was a debate between two PSU manufacturer regarding this 100Hz issue. If I recall well, one was saying that it was the AC 50Hz harmonic (2 x 50Hz) and the other one was saying that it was the strobe light generating this. I tend to believe that it is the strobe light since the 100Hz tone was also apparent in USA where we use 60Hz. The harmonic should have been 120Hz right? KABUSA strobe disabler does remove this 100Hz tone.

[CageyH]

So does fitting an external PSU and having just the strobe on the switch.
That is the way I have mine connected, and without the platter dots, the strobe serves little purpose.

[guardofmagog]

So does fitting an external PSU and having just the strobe on the switch.
That is the way I have mine connected, and without the platter dots, the strobe serves little purpose.

Hi Kevin,

I don't know if your strobe switch is sufficiant to remove the 100hz tone, I am no expert but it seems a bit more complicated than that. Here's an insert of KABUSA.COM website explaining this issue. You can find this info in the What's new section at the end of the page. For the PSU and Strobe light disabler you can find information in the Everything Technics Starts Here section.

I'm sure it will be helpful,

Eric


Jan 4, 2009
SL-1200 Power Supply Controversy
Just as there was lots of criticism of the '1200 arms before they were rewired and fluid damped, now there seems to be a new focus on the 1200's internal voltage regulator: A textbook 3 transistor slow start circuit that maintains the operating voltage at 21VDC at a runnung current of 259mA. You know, I did all this research years ago, so when I first looked at this UK site's data, I thought they had something, but I have looked closer and can now comment more intelligently.

A UK website is showing 'scope photos suggesting that the load regulation of this circuit is somehow unacceptable. I feel I have to point out a big error with this conclusion. It's so obvious when you study the numbers: Their data is not the showing the motor current at all, it is showing the strobe lamp current! Just look at the repitition rate, it is symetrical 10ms(100hz). Motor currents pulse at a very slow rate(1.65 Hz). If the motor was pulsing at 100 hz, like their 'scope photo shows, the motor would be humming along at some 2,000 rpm(100/3x60)! And it can't be ripple from the main capacitor either for that waveform would not be symetrical like they show. It is so easy to mis read data when you are expecting a certain result in advance. We see this done with tonearm resonance flexure plots as well as harmonic distortion plots. It is always important to actually "run the numbers" to get the true impact. It also helps to know what you are looking at.
Installing an outboard PS after the internal regulator may reduce the strobe artifact, but disabling the strobe itself is a better solution for then, the noise source EMF no longer exists.

The internal regulator responds very well to motor load currents, but is not "fast" enough to completely extinguish the strobe lamp currents. However, note that it is doing quite a good job as the regulation is still only 0.05% of the 21VDC operating voltage. When I saw this in my own research, I saw a much more cost effective solution to it: our SX-1200 Strobe disabler circuit completely removes this artifact and EMF at a very low cost. Because while you may only see 10mV RMS on the 21V main rail, on the other side of an isolation resistor, you have 16VP-P which produces yet another EMF field. The only way to remove it is to disable the current path to the strobe LED's.

[CageyH]

From what I read in the above, disabling the strobe to reduce the noise is very similar to not turning it on?

[guardofmagog]

From what I read in the above, disabling the strobe to reduce the noise is very similar to not turning it on?

Sorry I can't help you on this. If you are worrying about it you may contact Kevin at KAB by email. I emailed him a few times on different products and he is very generous in providing information.

[Marco]

That's rather interesting, and I suspect that Kevin is right again (as usual) ;)

The strobe light-disabler mod is one of those I chose to have carried out years ago, when I bought my SL-1210 from Kevin, and had it fully 'KAB modified'. I now feel vindicated in doing so, as indeed I do combining it with the use of a quality off-board PSU, although no longer one of Kevin's.

In any case, the strobe lamp no longer performs any useful function, once you've changed the platter!

Marco.

[Qwin]

The strobe light firing transistor needs removing from the board to silence it.
Even if you remove the strobe light, the transistor continues to ground the circuit at 50 times a second creating noise in theory when firing, though I don't know if anyone has measured this. The LED's in the strobe only flicker due to this transistor grounding the input at a speed of 50Hz. The trigger/controler for the transistor is one of the large chips on the board nearby, if you look at the PCB layout in the service manual the tracks are pretty easy to follow. I removed this transistor on my 3 modified decks and think I mentioned it in one of my build threads.

Also agree that removing the power supply and making it external should be the first step.

If you don't need the pitch fader or cueing light remove these as well.
When you unplug the pitch fader you need to bridge two of the pins on the board header, this is covered by someone on one of the threads and I may have covered it on my first build. EDIT: Its pin No 6 and 7 you need to bridge (join together). see this thread for details: http://theartofsound.net/forum/showthread.php?15537-Technics-1210-mk2-pitch-fader-fix-%28and-instructions-on-its-removal%29

There is a brief summery of my three projects on my website linked at my signature below. But the threads have discussed details not on their, you would have to search for them.

EDIT: I have bumped my three build threads so you can spot them easily. I also cover a straight arm modification.

[Khom]

I can't imagine how the strobe light electrical pulses can affect to mechanical hum. Yes, these pulses have a huge value (I measured approx. 80 mA peaks), but I checked needle positions on the disc (i.e. contact) and 1 mm above - results was different, it means that 100 Hz hum caused by mechanical (more precisely electro-mechanical) issues.

I replaced also some time ago strobe LED's with modern ones and reduced strobe current pulses to 5 mA, so this issue now is theoretical for me.

[Qwin]

I don't think anyone mentioned mechanical hum, more likely introducing electrical interference.
I was making the point that the x4 LED's will not be contributing much in the way of electrical noise.
Any electrical noise produced is more likely to be coming from the switching transistor that dims them, so removing the LED's without removing the transistor isn't achieving much. And yes how much, if any effect any of this has is somewhat theoretical, I don't think anyone has measured it, but in theory it is good practice.

The strobe on a Technics sl-1200 deck is after all a redundant device, the quartz lock guarantees it runs at the right speed. The pitch fader only cons the circuit into thinking it is running at the wrong speed and it increases/decreases speed by the amount set on the slider. The pitch fader needs correct calibration for the deck to run at the right speed when set to zero, but remove it and bypass its input by bridging pin 6 and 7 on the PCB header and the deck reverts to running and maintaining the correct speed.

I simply remove any of the items which are surplus to my requirements, it costs nothing, if I had a valid use for any of these I would leave them in. I suspect any gains by removing these devices would be small anyway, moving the PSU external and upgrading it or the internal regulator should give greater gains.