[hciman77]

As I explore the world of TTs (in the abstract sense anyway) I find myself looking at performance specs and puzzling about how these are assessed. How is rumble and especially SNR measured on a turntable, on a CD SNR is an electrical property but without a cartridge how do you measure SNR on a TT ? Also some noise must come form the record, is this factored in.

The specs on TTs vary massively some of the esoteric ones have noise levels that would be for practical purposes very close to inaudible i.e -80db or so, other less ambitious ones get to -60db or -70db.

Is rumble measured as audible or as breakthrough ?

Genuinely puzzled

 

[hciman77]

Looks like I am going to have to channel the spirit of Julian Hirsch...

 

[JadeEast]

I don't know how they measure rumble on a turntable.
If I had to come up with a way to measure a playback
systems rumble I would use a test record with a pure
tone at 2k Hz calibrate the signal playback level to 0db
then apply a notch filter around the frequency any then
measure the amount of low frequency generated by
the playback system. Measuring the performance of
an analog rig has many variables but still should be
possible with a test tone signal on a record.

Wow, Flutter and Rumble from the drive mechanism
along with noise from the bearings can all get into the
system. Stylus shape can vary the amount of noise
picked up along with the conditions of the record being
played. The pre-amp for the stage can have its own
performance as an amplifying device in the system.
Lots of chances for noise.

There is very little if no independent testing of
analog playback it would be interesting to see
how the performance claims of manufacturers
related to independent test findings.

 

[fran]

Its almost impossible. In fact I remember reading, I think it was the review that Fremer did on the Continuum table in Stereophile, that even on that table there was no specified wow! $125K and no specs!

So its a case of reading around on opinions and if at all possible some listening. Whats your budget? And what other equipment do you have, ie rest of system but also do you have arm/cart/phono stage already?

Fran

 

[hciman77]

Quote:

Originally Posted by fran /img/forum/go_quote.gif Its almost impossible. In fact I remember reading, I think it was the review that Fremer did on the Continuum table in Stereophile, that even on that table there was no specified wow! $125K and no specs! So its a case of reading around on opinions and if at all possible some listening. Whats your budget? And what other equipment do you have, ie rest of system but also do you have arm/cart/phono stage already? Fran

I am still at the toying with it stage of proceedings. But If I did go vinyl I guess I would be looking at $500 or so, given that that would be almost twice the cost of my CD sources put together I would have trouble justifying more.

With more reading I find that Sansui were good about publishing specs and even showing the relevant graphs, some of their older Direct Drive TTs had pretty respectable performance parameters in terms of noise and rumble.

Having said that it would be hard to beat the published specs of the Technics SL1200 which had rumble down at -78db weighted, yet this TT is often looked down upon because it is used by DJs

 

[fran]

A friend of mine bought a Project RPM5 and I can tell you its a great performer. Comes with an arm and cart (which you use until you get a better performer, if you know what I mean!). Other than that you're looking at something like a Thorens TD160. Not a bad performer, esp if you tweak it up a bit. Some of the older DD tables can be good too, but for many, if they die, no parts are available to fix them.

You should also know that you will need a phono stage - you may need to factor that in if your amp doesn't already have one. If you're looking for recommendations for carts/phono stages, can I recommend a Denon DL110 cart and an NAD PP2 phono stage. Both perform well above their price point.

 

[Publius]

Look at test records for the tones they use for IEC wow/flutter measurements. Some of those measurements, IIRC, require a frequency discriminator, and measure the frequency modulation caused by the wow/flutter on a tone.

It's worth noting that good direct drive turntables advertised their extremely good wow/flutter numbers as indicating their speed stability, something which generally reflects their subjective evaluation.

Many of the turntable measurements aren't impossible to make, but it is very hard to isolate a result to make it meaningful for consumers. So many of the metrics are interconnected, depend on environmental noise, alignment, cartridge quality, etc.

In my opinion SNR numbers are a complete crap shoot and you can get them as low as -90db without really changing the design of anything. The SNR number is meaningful for an individual system, but what's more useful is looking at the background noise spectrum for a silent groove. But even that is dependendent on a phenomenal number of factors: vinyl formulation/quality, how clean the record is, pressing quality, how clean the stylus is, cartridge type, stylus resonance, tonearm resonance, environmental noise (and its isolation), electrical shielding, preamp background noise....

 

[hciman77]

Quote:

Originally Posted by Publius /img/forum/go_quote.gif Look at test records for the tones they use for IEC wow/flutter measurements. Some of those measurements, IIRC, require a frequency discriminator, and measure the frequency modulation caused by the wow/flutter on a tone. It's worth noting that good direct drive turntables advertised their extremely good wow/flutter numbers as indicating their speed stability, something which generally reflects their subjective evaluation. Many of the turntable measurements aren't impossible to make, but it is very hard to isolate a result to make it meaningful for consumers. So many of the metrics are interconnected, depend on environmental noise, alignment, cartridge quality, etc. In my opinion SNR numbers are a complete crap shoot and you can get them as low as -90db without really changing the design of anything. The SNR number is meaningful for an individual system, but what's more useful is looking at the background noise spectrum for a silent groove. But even that is dependendent on a phenomenal number of factors: vinyl formulation/quality, how clean the record is, pressing quality, how clean the stylus is, cartridge type, stylus resonance, tonearm resonance, environmental noise (and its isolation), electrical shielding, preamp background noise....

Interesting, so basically it is somewhat finger in the air stuff

.

After noise my guess is that the most important hygiene factor (factor to be removed to make things acceptable) is speed stability. I saw a review of a Rega P1 a few days ago where the reviewer effectively said that you might notice some pitch instability on Piano music. When I picked my jaw up from the flaw I wondered is that a problem that is always worse on belt drive or just a matter of implementation. Audible Pitch instability would drive me bananas, I have a lot of piano music.

 

[Publius]

Ah. Therein lies one of the greatest controversies in audio. You should be able to search for the belt-vs-DD debate on pretty much every audio forum, but I would look hard on here, Audio Asylum, Audiogon and stevehoffman.tv for the particularly juicy stuff.

In my opinion, belt drives are only going to be truly stable with extremely high mass platters and when using servo control. My MMF5 has considerable speed control issues - and it's supposed to be in a higher performance class than the P1! Also there's something of a running gag on Regas running too fast, like 1% or so. I'd recommend that you look at Stereophile's P1 review to find the real scoop.

In comparison, you are not going to find a single person in the world who has an objective, measurable beef with the 1200's speed control. (However, I don't own one yet, so I can't tell you how it sounds.)

If you are extremely sensitive to wow/flutter then I would think twice, maybe three times, about getting any belt drive that costs less than $1000-2000. I would also not think twice about getting a stock 1200 or even an AT-PL120. Whatever you do though, audition the table before keeping it for good.

 

[lini]

Quote:

Originally Posted by hciman77 /img/forum/go_quote.gif (...) When I picked my jaw up from the flaw I wondered is that a problem that is always worse on belt drive or just a matter of implementation. Audible Pitch instability would drive me bananas, I have a lot of piano music.

It's a matter of implementation. But if you're really worried, you could always go for one of Dual's former top models with quartz controlled belt drive (e.g. CS5000, CS750(-1)...). But I'd doubt that you'd notice speed instability even on a simpler construction like your average Thorens TD14x/16x.

Greetings from Munich!

Manfred / lini

 

[trains are bad]

It is indeed a matter of implementation of whatever design is chosen. IMNSHO, the Technics DD serves as the benchmark for actual turntable performance. I've fiddled with belt drives before, and there's just no point in using anything but a technics...

 

[fran]

If belts are so bad and DD so good, then why do so many of the high end tables use a belt drive. Eg Linn, Clearaudio, VPI etc etc?


Its all about implementation as said before, and done right belts are AOK. There are other things too to consider as much as speed stability (and yes, speed fluctuations drive me nuts!). Things like plinth and platter construction, arm mounting etc all are important too.

FWIW, on my ariston RD80 (similar to LP12) there is no discernable speed problems, except when the belt is dirty or worn. Violins and harpsichord are also great for showing up and speed probs.

Fran

 

[jp11801]

Quote:

Originally Posted by hciman77 /img/forum/go_quote.gif Having said that it would be hard to beat the published specs of the Technics SL1200 which had rumble down at -78db weighted, yet this TT is often looked down upon because it is used by DJs

while I am a Linn lp12 lover and doubt you could pick up woo and flutter on it, the 1200 with a modded arm and some chassis work should be a very good table. If you do a search for it you can come up with the rega arm adaptor for the 1200 and I've seen some great dampening mods for these as well. You can start slow and build up as you get the cash and itch.

PS I can send you a needle drop of vinyl if you want to get a feel for it.