The Technics SL-1200 GAE/G/GR general questions thread

The start button on my GR is 'loose', has some freedom of movement, I think it's built that way. I imagine the switch is made by a contractor and it's the exact same switch no matter where it's made.
'jap'?
Not cool

 

The start button on my 1200G is like an exact replica of the ones I had on my MK2, MK4 and M5G...
Same for the speed selection buttons, other than the LED color (and the MK4 having 3).

 

Bottom of switch assembly
switch
Push button

 

Switch is made in Japan by Omron and shipped the Malaysia

 

Are you sure those are 1200G/GR parts?
The PCB looks like the one used in the legacy 1200s because of the wavy traces (typical for hand drawn traces used back in the days - PC drawn are generally straight unless it’s for HF applications).
And the black connector looks like the ones used until mid 90s.

 

Yeah, for some reason, there are people who take issue with some of us utilizing features that are part of the appeal of this design (what would the purpose of interchangeable headshells be if not to, you know, change headshells?). I would do exactly what you explain in that situation, too. Why not, right?

 

Yes, also the fact that it’s not mentioned in the manual. I don’t think Technics means for it to be done, but that doesn’t mean it can’t be done.

 

As far as I can tell, there is one lone source for that 9 gram figure, and that source doesn’t cite its source or explain how that was measured. Since the GR arm wand doesn’t seem substantially different from a mk2 arm wand, most people assume it’s 12 grams, which was the published spec for the mk2 arm. I’d imagine the G could be different because it’s a different metal. But, no, I haven’t seen anybody give a definitive answer.

If someone was to choose a cartridge assuming 12 grams is right and then measures the resonance only to find it needs weight added, that’s easy enough to accomplish with a different headshell. Hard to go the other direction, though, if assuming it’s 9 grams and finding things are too heavy. So I think the safe side may be to assume 12? Maybe?

 

The resonance tests I did a few weeks back lead me to believe that it’s closer to 9 than 12. Using a calculator, I should get about 8Hz resonance with an Ortofon 2M Red if it’s 12g, but I measured 9.04Hz, which I would expect if it was 9 or 10g. I haven’t measured the arm or done extensive testing, so I’m not making any declarations. But it wouldn’t surprise me if the effective mass is less than 12g.

 

But if you really measured 9 Hz resonance frequency and think the Ortofon lateral compliance spec is accurate, that would imply the tonearm effective mass is about 7.5 grams, which seems pretty unlikely.

You said a few pages back that you tested the VM540ML, do you know what frequency that measured on the arm? We've seen recent test results of the resonance on the old SL-1200 arm.

It's obviously hard to try and calculate the tonearm effective mass from a resonance test since there aren't many precise known values to use in the equation, so if you already have the arm and cartridge, more meaningful to just check and see that it is OK. Sometimes we get a little carried away with running the numbers

 

How in the heck do you measure an arms resonant frequency?

 

According to my notes, 8.79 Hz. On the stock headshell, of course. I also measured it on a Jelco headshell that’s a good but heavier then the stock and it was under 7Hz.

 

In the review measurements of the VM540ML with the stock SL-1200 Mk6 they measured the resonance around 7.5 Hz, which leads to the reasonable compliance number of 23 cu. Your measurement again puts the tonearm effective mass in the unlikely 7 gram range.

 

Maybe RX is on crack. What do you use for analysis? I can try again with something else.

 

Audio Interface

Just record a few seconds of audio or silence between tracks, or even just set the needle on the record without it turning, or record during cueing, and look at the spectrum, should be pretty obvious unless well damped or filtered out in the preamp ... I think below was just an environment test when I just had the needle on the record without it playing to check the background vibrations - there was some construction noise in the neighborhood, that's what some of the 30Hz noise is from, and some 60Hz AC components ... this was my old tonearm with around 13 grams mass and the AT-OC9XML, which is fairly high compliance, so resonance is pretty low at around 7-8 Hz. It's lower when the record is playing, down a little below 7 Hz.

 

When I calculate eff mass for the GR I come up ~18- 20 gm with my cartridge

I estimated arm/headshell/cartridge like this.
Arm zeroed
CW 100 gm + tube ~ 120 gm
d to CoM CW ~ 4.5 cm
d pivot to stylus 23 cm
4.5 / 23 x 120 = 23 gm

eff mass = (100 x 4.5^2)/(23^2) + (2 x 23 / 3)
= 3.8 + 15.3 ~ 19 gm

 

I'm sure most people realize, but I should probably still mention in case it's not clear, the spectrum above is captured after the phono preamp so shows the RIAA equalization applied, and hence the 6dB/octave rise below 500 Hz, and the 6dB fall above 2 KHz. It doesn't really make sense in this context since the record isn't playing so there is no signal that needs RIAA equalization, but that's my normal audio capture chain from the turntable. It does show why you need to be careful with controlling the tonearm resonance because the effects can be greatly exaggerated due to the phono RIAA equalization applied, which does stop rising when the signal is below 50 Hz, but that is still a lot of bass boost being applied to the resonance signal from the cartridge.

 

That all start buttons on SL12x0's have a degree of play is a point of fact; as to whether it's "wobbly" is a subjective judgment.

 

I think I’d have to be real picky to notice anything I’d call “play” in the start button on mine. I don’t think there is any more play than the buttons on any other piece of electronics gear I own... it seems to function just how any other button functions, right?

 

As with any 1200, you can feel some springiness in the, well, spring, before the switch engages. Is that what he’s talking about? Does he appear to have any prior 1200 experience?

 

Quite possible he is talking about Power On switch, which is a turning thing, not a button.

 

I agree, these are mass produced assembled electronic products some play in buttons especially some as big as the start/stop button is expected. I understand these tables are not cheap and perfection is expected but nick picking over trivial things that don't affect functionality is imo not worth it especially if you're after the technics DD sound.

 

Strange

The start/stop button on my GR is all in caps.

 

I guess I’m just not sure what else I should be expecting from that button. It seems completely fine to me.

 

Managed to partially setup up this GR beauty yesterday. Very impressed with the premium packaging and finish. This is not a cheap dj turntable. Feels and looks like pure quality! It was made in Japan according to the box.