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

If anyone cares? I now have 200 hrs. on my GAE & my 150 mlx. Did a recalibration on the VTA/antiskating, holding @ 160 gr. & it's opening up (coming to life). Some early thread, said about 800 hrs. it's fully broken in. I hope my tubes last that long.

 

Well... Over here in the Netherlands it’s allowed to rip off customers.
But it’s still bad practice regardless of it being allowed.

 

???
rip off?
The NEC is not a utility, it is an installation/construction standard.

It's almost required practice here.
It's just used as another grounding electrode.
The more the merrier, lol.
Another parallel path.

 

That, I agree with
However, I do wonder if it’s possible to get a loop between rods via the soil.

 

From what dealer? Malaysian-made? Would like to hear your quick initial reaction to the unit once you've had a chance to give it the evil eye. Thanks.

 

Has anyone found a fix for the squeaking noise that happens when tone arm is lifted and moved toward the song.

 

Lift high enough to clear rubber pad.
Always a chance to squeak when you drag it.

 

I think that is just an issue when new, squeaky rubber against the cueing peg or whatever it's called. My 1500C, purchased in May, did it for a while, does not anymore. Any downward force while moving the tonearm will also cause it.

 

It depends on the current it is carrying.
If a lightening strike it will spill thru all inversely proportional to each electrodes R.
So the whole grid is energized and current is flying everywhere until V is equalized.

If a hot conductor ground faults the current will flow thru earth to the rods and back to then source, the xfmr secondary.

Again each will see 1/R current but very little should flow rod to rod once the current is in the rod since its R is <<<< less than the soils R.
This assumes everything is bonded together.

 

Use your finger to wipe the rubber on the tonearm lift.
The squeaking will go away for a few days.
Mine still squeaks after about 3 years.

 

Brushing the lift with an Ortofon stylus brush will make the squeaking disappear temporarily. A high mass cart will make the squeaking disappear too. I do not wipe with finger since the oily deposit on the lift will dry out and create a crusty look that is hard to reach to remove from crannies.

 

Didn't work for me.
Tried both the 2M style brush and the DJ style brush.

Sounds more like a theory to me.
I've done it for years (on other Technics TTs and certain Hanpins) and it always worked for me so far.
Don't use greasy snack fingers though - you don't want parts of your turntable to turn "Doritos orange"

 

Answering a month later...

The Audio-Technica cartridges benefit from unloading them. That means both less capacitance and less resistance loading (a higher R value) than conventional, and needing short cabling and preamp close to the turntable.


(the slight "tilt" to the razor-flat response is part of the simulated preamp design's real-world compensation. Crisp subsonic filter also.)

Giving higher-value resistance than standard 47k may mean modifying the phono preamp; it's the wrong direction for loading plugs. Giving capacitance as low as 50pF means removing any loading internal to the preamp, and providing only 25pF for internal tonearm wiring and 25pF allowance for 1 foot of low-capacitance external wiring.

The result is extended frequency response (0dB @ 20kHz) with just a touch of peaking at our hearing limit, which compensates for the mechanical ultrasonic resonance of vinyl-stylus interface and the slight dip below it.

 

This is a simulated model that only accounts for electrical resonance and not mechanical, correct? If so there’ll be a rather sizable gap to real-world performance.

It’s impossible to remove all capacitance internal to the preamp due to strays, Miller, etc. Mine is about 25pF. Doesn’t leave much for cabling and connectors.

 

The mechanical resonance comes about from the springiness of vinyl. Under a groove's acceleration, the inertia of the stylus compresses the plastic underneath it, which then springs back.

Its frequency and response is affected by the vinyl and plasticizer formulation, temperature, etc, outside of the the mass of the stylus, so, like anti-skate, isn't something that can be universally compensated for in design. You also might play styrene or acetate. Freeze a record before playing, and the vinyl is harder. The peak is well above 20kHz; it is only a slight expected dip in audible high frequency range that the electrical peak should compensate.


Besides resonance, there are, of course, other mechanical factors that affect the response of magnets inducing current in coils.

You'd think that the cartridge specifications (such as 47k 100pF-200pF given for all ATs) would actually be specified to yield the flattest response possible, including the resonances and mechanical reproduction, but instead they seem rather to sell you that the cartridge is still compatible with the preamp you already own. The brightness or even harshness that some associate with Audio-Technica is instead from believing the loading specs.

I've seen 28pF for a 1200G and 22pF given for 1200GAE tonearm wiring (the change in plugging the interconnect into the turntable), so 17pF/ft RG6 to a solid-state preamp makes low-cap achievable. It is only the excessive load capacitors added inside (or on the amp board of the 1500c) that you need to go after with some wire snippers.

PS a flat electrical response in high frequency also means a minimum phase shift.

(I transcribe at low speed to push these 15kHz-20kHz perturbations up to 30kHz; a trick where the new 1200 will only give you -16%)

 

For the last three months I have been running a VM540ML on a 1210GR, using stock interconnects to a Parasound P6. I have no sense for “extra crispy” except on Classic Hauser. Yet this sense of brightness also appears on the CD of same so perhaps the cart is just yielding a full performance? At any rate, I do not find it to be objectionable; however, I am now running a Shure V15 type III with JICO SAS-B stylus, which has no extra crispy signature and seems to be somewhat more nuanced too, in addition to other characteristics deserving accolades. So, the VM540ML is likely to rest for awhile.

 

The cantilever itself has mechanical resonance. There’s a thread on diyAudio from years ago where we built electrical models of cartridges representing both their electrical and mechanical properties. Extend your model to 150pF and 47K - let’s see how the simulation stacks up to measured response.

AT have done flat in the past. The 150MLX is flat right in the middle of the recommended capacitance at 47K. The latest series seems to mirror typical MC response.

Have you ever measured (oscilloscope) the actual capacitance you’re running to confirm your calculations? It’s a bit of a pain as you have to tap you’re phono stage pre-EQ, but can be very enlightening.

 

Is there honestly a huge difference between the 1200g and the 1200gr?

 

Why do you ask again?

 

@JP and @harby

why not shunt compensation?
Could be optimized in matlab or an excel spreadsheet

 

Accurately tweak the little capacitance adjustment knobby on my 14pF Tek probe or set up the RLC bridge with its wandering frequency generator to ring a cable? This is so much easier and can measure the distance between two 6 inch wires; here a 1pF RCA jack:



And here, just because I like you, phono input capacitance:


So the answer is yes.

Don't know what you mean by "tap pre-eq", as I universally use buffered SS preamps, not some tube contraption with, for example, first-stage driven negative feedback to make the Miller input capacitance vary between 25-250pF on top of a 330p disc and completely happenstance response.

One thing I don't have is a trustworthy CBS or JVC test record, and won't be getting a VM540 motor as I'm all p-mount right now. Just ears and results.

add'l: just stealing this from another thread of mine to show another benefit of a shift in loading:

 

EQ = RIAA if applies. My MM pre is a flat INAMP so not something I need to worry about.

Grab an STR-100 for $20 - it’s close enough. You may be surprised what happens when you connect those bits together in an environment along with the impact of an active stage.

My measurements appear to vary appreciably from your models which is why I asked for the 150pF/47K simulated plot for the 540, as I can’t get to 100pF.

 

Sure. It is essentially a visual depiction of your concerns to which I initially replied, and mirrors the response plots you later posted - peaking and premature fall-off:

You can see that going below 100pF is poor without the increased value in internal resistance loading.

 

In a subsequent post is an actual plot - quite different from your simulated plot.

 

:My phono pre has 47K and 100K, how much more resistance are you talking? Would setting it a 100K be too much resistance, if that's possible?

By the way, great analysis and info above.