Turntable speed

[davidsrsb]

There's a setting inside the SL1200 to set the '0%' speed. To do it properly you need a frequency counter, perhaps your multimeter does this?

A general purpose crystal oscillator will be better than about 100 ppm accuracy.
True frequency counters are much better than this

 

[the_bat]

Just to put these numbers into context, if my maths are correct (always an important caveat) then the difference between 33.33 and 33.44 is approximately 0.6 of a second over a typical 3 minute track.

 

[sonddek]

Interesting thread - especially the Sutherland laser video showing the effects of stylus drag on a very massive deck. Lots of people still seem to think stylus drag does not affect the performance of turntables.

Have you tried the app on the LP12 while playing a record?

 

[Whaleblue]

If stylus drag impacts speed (on “non-locked” TTs), then why isn’t the weight of a parcel tape centre plus phone not a significant factor? Perhaps Heisenberg will chip in?

 

[a.palfreyman]

I believe that it is because the phone / tape roll support only add mass / inertia and not drag.

 

[Tony L]

Interesting thread - especially the Sutherland laser video showing the effects of stylus drag on a very massive deck. Lots of people still seem to think stylus drag does not affect the performance of turntables.

I’ve been convinced of it for a good while now, arguably forever. I’m also convinced it is not a constant force.

I remember clearly when I “upgraded” my first system’s Lenco 75 to an Ariston RD80 really missing something despite obvious improvements elsewhere, but being so early in my journey as a hi-fi geek I couldn’t articulate exactly what had gone. In hindsight it was that rock-solid pitch, timing and slam I now associate with high-torque vintage idler decks. It all came rushing back over a decade ago when I compared an early ‘60s Lenco L70 compete with its agricultural arm and a basic Pickering V15 MM to my Spacedeck. The latter killed the Lenco on everything except that drive, solidity and punch. Exactly what I remembered missing from my very first L75. I’m now at the point I’ll always sacrifice a bit of noise-floor for it. I can’t see myself ever moving from an idler deck now.

The TD-124 with its heavy iron sub-platter and Retrotone upper platter combines high torque with a substantial amount of rotational mass (>5kg IIRC) and it just sounds so rock solid and in tune to my ears.

PS I’m not knocking the Spacedeck, it is a very, very good turntable IMO. I just personally prefer a vintage idler. There are no perfect turntables, only compromises, so taste is everything. I guess as an old-school flat-earther at heart I still value pitch, timing and slam over noise floor, micro-detail etc.

 

[mayebaza]

Although not the cheapest of items, I have found using Longdog Audio Quartz Turntable PSU MKII will dramatically improve speed control and sound quality.

 

[Warszawa]

As mentioned in a previous thread, don't take these apps as gospel unless they concur with a strobe disc. My iPhone X reads it as slightly too fast with two different apps. The stroboscope on my deck and a strobe disc disagree.

 

[davidsrsb]

When you know how accelerometers in a phone are actually read by the CPU, meaningful wow and flutter readings are a miracle.

I also don't see how it is possible to place a phone on the platter sufficiently accurately not to throw everything out of balance

 

[Paul R]

A general purpose crystal oscillator will be better than about 100 ppm accuracy.
True frequency counters are much better than this

The SL1210 Mk2 has adjustable speed, for DJs to do their things. Inside the deck is an adjustment for the '0%' speed adjustment position of the slider. The adjustment is performed by measuring the presence of 262.08kHz at an internal test point. I don't know how the pitch control is actually implemented. The frequency to calibrate is a 16th of the crystal nominal.

My original condition SP10/2 (no pitch control) is measuring, after a bit of warm up, 33.3331, 45.0018 and 78.2599 using a Raspberry Pi and some magic. It's too much of a coincidence not to be right, although that 78 result is bothering me now.

 

[davidsrsb]

The SL 1210 Mk2 used a CR oscillator, in principle like a NE555, and PLL

 

[Craig B]

A digital laser photo tachometer, such as this AGPtek model would be

The SL1210 Mk2 has adjustable speed, for DJs to do their things. Inside the deck is an adjustment for the '0%' speed adjustment position of the slider. The adjustment is performed by measuring the presence of 262.08kHz at an internal test point. I don't know how the pitch control is actually implemented. The frequency to calibrate is a 16th of the crystal nominal.

My original condition SP10/2 (no pitch control) is measuring, after a bit of warm up, 33.3331, 45.0018 and 78.2599 using a Raspberry Pi and some magic. It's too much of a coincidence not to be right, although that 78 result is bothering me now.

Is should bother you less when you consider that it is pointless playing 78s without a broad pitch control.

If absolute speed accuracy (vs. wow & flutter) was worth bothering with (within reason) then a digital laser photo tachometer would be the ideal test tool. This AGPtek model sells for circa $27. online...

 

[Paul R]

Is should bother you less when you consider that it is pointless playing 78s without a broad pitch control.

It doesn't actually bother me at all...

Especially given the specified speeds are 33 1/3, 45 and 78.3.

 

[wd40addict]

original condition SP10/2 (no pitch control) is measuring, after a bit of warm up, 33.3331, 45.0018 and 78.2599 using a Raspberry Pi and some magic. It's too much of a coincidence not to be right, although that 78 result is bothering me now.

78.26RPM is the standard speed for a '78' in 60Hz countries. 77.92RPM in 50Hz counties.

https://web.library.yale.edu/cataloging/music/historyof78rpms

 

[Paul R]

Technics knew what they were about. I'm really impressed it's coming out so close. I suppose crystals don't drift, but even so.

 

[Craig B]

It doesn't actually bother me at all...

Especially given the specified speeds are 33 1/3, 45 and 78.3.

What I meant was, were you a collector of early 78s, you'd soon find that not all were actually cut at 78rpm.

Played at 78rpm, early Caruso (68 to 70rpm), for example, would sound like a castrato; this before we take into consideration that there were no standards for recording equalization.

 

[sonddek]

I’ve been convinced of it for a good while now, arguably forever. I’m also convinced it is not a constant force.

I remember clearly when I “upgraded” my first system’s Lenco 75 to an Ariston RD80 really missing something despite obvious improvements elsewhere, but being so early in my journey as a hi-fi geek I couldn’t articulate exactly what had gone. In hindsight it was that rock-solid pitch, timing and slam I now associate with high-torque vintage idler decks. It all came rushing back over a decade ago when I compared an early ‘60s Lenco L70 compete with its agricultural arm and a basic Pickering V15 MM to my Spacedeck. The latter killed the Lenco on everything except that drive, solidity and punch. Exactly what I remembered missing from my very first L75. I’m now at the point I’ll always sacrifice a bit of noise-floor for it. I can’t see myself ever moving from an idler deck now.

The TD-124 with its heavy iron sub-platter and Retrotone upper platter combines high torque with a substantial amount of rotational mass (>5kg IIRC) and it just sounds so rock solid and in tune to my ears.

PS I’m not knocking the Spacedeck, it is a very, very good turntable IMO. I just personally prefer a vintage idler. There are no perfect turntables, only compromises, so taste is everything. I guess as an old-school flat-earther at heart I still value pitch, timing and slam over noise floor, micro-detail etc.

Real wisdom here. I came to this same conclusion by a completely different journey, but I think Tony is completely correct. Every increment of speed consistency matters while playing dynamic signal. There is little point in checking the speed of a deck while it's not playing music. What happens when the stylus engages is a different story. Speed consistency, and lots of it, is the indispensible measure of magical vinyl playback.

 

[Rockmeister]

I read an article somewhere...a stereophile test report? on speed and how all Regas and Linns run fast, with some speculation as to if this may contribute to their 'signature' sound?

 

[John]

Interesting thread - especially the Sutherland laser video showing the effects of stylus drag on a very massive deck. Lots of people still seem to think stylus drag does not affect the performance of turntables.

Have you tried the app on the LP12 while playing a record?

Here you go taken with my 8 year old genuine LP12 belt.

 

[John]

I read an article somewhere...a stereophile test report? on speed and how all Regas and Linns run fast, with some speculation as to if this may contribute to their 'signature' sound?

My Rega Planar 2 runs at 34.10 RPM and there’s no way to calibrate the speed. LP12’s are likely calibrated at the factory, mine is running at 33.33 using a calibrated iPhone app called RPM.