Pinky's Funky Rambling's....!!!

[jammy395]

You have no taste Jammy, it is industrial art, built like tank.

Yep you may have a point Doc - Im sure I saw the same TT in the 1947 Joules Verne movie.

Bet its still bloody working.........

[Oldpinkman]

Admin - not acceptable ad hominem, 1st strike.

Pinky you have to learn to accept other peoples opinion have as much value as your own.

[Daniel Quinn]

pinky , you need to chill out , these dd's acolytes warble far more than our beautiful d.c powered PT'S , you just have to let them carry on being delusional . i could do with 2nd hand price pt's declining so i can line up some spare parts :D

[Dr Bunsen Honeydew]

There you go. I am not offended by DQ's opinion!

[Dr Bunsen Honeydew]

Pinky where are you.



We are missing your ramblings.

[Oldpinkman]

Out enjoying the craick. I seem to have fallen so far behind I don't know where to start catching up. Lets do warble - a term which came to prominence in the aos platter wars. For sure it is the stand-out weakness on my PT. (and, although a bit less, on your anniversary DQ). But it is not the only aspect of music reproduction. Clearly I am not very bothered by it. Neither is the Mrs. I suspect it's a bit of a hi-fi thing, cos neither are most of my musician friends.

I am more sensitive to it now after the platter wars and a protracted session listening to piano and sustained vocals at the factory to see if one platter warbled when the other didn't. So I now recognise the phenomena and want to address it, when I had spent 25 years not being fussed.

But I don't want to go back to warble-free music sounding like an early Philips cassette deck on ferric tape, compared with a slightly warbling nakamichi on dolby c with basf super chrome-dioxide. Which is what I, and Mrs s and DQ appear to notice first.

For project "pimp PT" I have a cunning plan.

[Oldpinkman]

Regarding the DD / belt trade-offs, its worth bearing in mind that my "warble" auditioning was comparing 2 platters on a Technics DD system and not belt v DD. That I could hear no difference I don't think reflects my insensitivity to the problem. The 2 platters I was listening to were broadly the same weight, and based on Arthurs back of a fish & chip packet calculation the "heavy" one had the same rotational inertia as the stock Technics platter. The issue was not belt de-coupling but the effect of mass on the servo control mechanism in the electronics. As such it was not mass, but rotational inertia which was key - a point which appeared to cause as much confusion as the carbon-fibre arm tube on AOS.

The two platters didn't have different warble because they were, within a range, the same rotational inertia (and not that different mass). What was really funny was a post by Marco earlier about the Mike New Copper platter, and how wonderful it sounded, and how it demonstrated the awesome power of that fabulous Technics motor. It weighs 10Kg with more of the mass at the edge of the platter. (The standard technics is about 1.8Kg and the other 3 being debated in a range from 1.4 to 2.2Kg). The 10Kg platter was so heavy that one of the forum members couldn't get his up to speed at 45rpm. I have never heard it, but would not fall over from shock if that was a bit outside the design parameters for the servo on that TT. But not a couple of years before, Marco "the warble finder general" was singing its praises unreservedly.

Quoting from AOS thread "The Mike New platter, Oyaide..." post number 44 - il duckie makes the following comments of a 10Kg platter "The sonic presentation of the SL-1210 now has a power and authority, together with a sense of ease and lack of strain that I've never before experienced" and "and the superb Quartz controlled D/D motor and control circuitry take the extra mass of the MN platter in their stride (from initial start-up onwards) and deliver a musical presentation with uncanny realism that engages and beguiles one in a way which almost defies belief. "

Before you ask Doc (and you did ask me to ramble) there are 2 points. The first is just to remind us of Marco crapology and how one minute it can establish a 10Kg platter is no problem for a Technics servo, and but a couple of summers later the same Duckie can be saying how he knows that heavy platters are a problem and has always said so (during the platter wars thread, bolstering his mate Martin T)

The 2nd is that a lot of warble, is to do with the servo mechanism on DC motors. And in that respect, belt drive has some distinct advantages which my mate pointed out in the AOS thread. Vis - the much higher rotational speed of the belt drive motor makes it easier for the servo to control, because it can use more frequent smaller sized corrections. Enough for one ramble

[Daniel Quinn]

So now you can hear warble :D

whilst my anni is modified , I don't hear warble or blurring of notes especially on piano . Indeed when I got the maxon motor the sound of the piano on Tori Amos little earthquakes was one of the first thing I noticed . I did have an export also which had an ac motor and I could hear warble on that only on sustained notes at the end of a record . Lloyd cole has several songs which end with a sustained guitar note and you could hear this waiver . But this does not happen with the DC motor .

So for me it simply aint an issue .

[Oldpinkman]

Even I couldn't pretend my PT is rock solid. As I said - it isn't what my ears (brain?) mostly pick up on. But after the monster session as part of the platter wars, I am a bit more aware. It is pretty slight. As I said, I believe, there are 2 quite separate possible causes. The first is instability in the motor itself, whether DC servo issues or AC cogging or whatever. The second is the effect of the belt pulling on the bearing from one side only. Now, I didn't quite get the Doc's technical bit on this, and Arthur has been having a bad hair day or 2 so wasn't approachable, which is why I've avoided responding and talking out of my a***. However, in a review of one of the TT's that use vector which I found by googling it comments

"The K-drive configuration prevents the drive belt tugging at the platter and causing it to oscillate around the main bearing. What's more, the K-Drive system uses asymmetric slave pulleys that, by rotating at different speeds, ensure that the drive does not generate any resonance. All of this adds up to a ferociously stable platform that spins the record at an absolutely constant speed." so maybe Arthur with his 25 years experience addressed that point.

Related to the complexities of motors and their controls, AK had a problem with the early LSD's. He shipped a batch to the USA, which had been exhaustively bench tested, and the distributor reported speed drift. Not warble, but the absolute speed "wandering off". AK replaced every component in the control electronics, and resorted to using his "K-drive" (his rolls-royce control electronics for his posh TT) and he still had the same problem. Apparantly stable - leave it running overnight - and it had drifted. So since it wasnt' the electrics, it had to be the motor? Interestingly, the problem was only at 33rpm not 45 rpm. It turned out the motor, which is widely used elsewhere, is stable within a speed range, but not outside it. The problem is the motor itself. The solution was simple - up the speed, and reduce the pulley size.

Funny things these motor systems, and as a good subjectivist I trust my ears not measurements or theory!

[Daniel Quinn]

My pt is of course sans springs , so belt pulling is not an issue . It was on the export . I have a tabrizi with intelligent {?} counter weight and on the export you could see it rock back and forth ever so slightly . it was a trade off with how tight you made the motor to the top plate .

it is also funny you should say that about the pulleys , I tried o/l motor units [ terrible warble and speed drift ] but eventually ended up with a maxon motor and a £50 lab bench variable dc power supply and the origin live smaller acrylic pulley size out of necessity [ lost the metal pt one ] and I now have experienced no speed drift in months .

now they castigated me on pfm for this power supply and its lack of sophistication [ speed monitoring ] , but even a radikal only calibrates the speed on switch on and any idiot can do that with a stobe :lol and listening is sufficientt on the trot speed analysis for me .