Bigman80
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Post by Bigman80 on May 2, 2020 11:11:45 GMT
The Feickert is utterly useless for measuring wow and flutter. You have no access to the internal maths and the filtering is unknown, it's a Sh#t show. You either need an optical encoder disk, or a standardised test record, not the hifi news or analogue productions ones, a real ISO test disk, and then perform a frequency demodulation. Rega use an optical encoder disk, glass platter, litho engraved, for setting up their p10s, this is currently the limit of testing, a 1200 mark per rev disk giving an potential 0.15 degree raw accuracy that can be massively improved by performing a FIR on the output. Sticking a phone on the platter doesnt come close. Probably worth mentioning the lp12 rumble is high -70db A weighted. Mag levving the bearing gave another -3db improvement when we did Ynwoans deck, which was clearly audible and easily measurable. Spot on.. |
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Post by sq225917 on May 2, 2020 11:17:21 GMT
For a laugh heres a 1210 with an GM demod using the analogue productions record. www.flickr.com/photos/59684834@N08/10711325725/in/album-72157629553367709/Yeh its a little octagonal, it should be a perfect circle. Basically it has a 16th of a revolution speed error, hunting. Dont mod your 1210 if you dont know what you're doing, that heavy platter and 'new' bearing will screw up the logic that the speed control uses. |
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Post by rexton on May 2, 2020 11:26:57 GMT
Interesting reading this thread as I have both the 75 and the 1210. Nice to see the arguments for both sides. Carry on chaps!
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Bigman80
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Post by Bigman80 on May 2, 2020 11:30:49 GMT
For a laugh heres a 1210 with an GM demod using the analogue productions record. www.flickr.com/photos/59684834@N08/10711325725/in/album-72157629553367709/Yeh its a little octagonal, it should be a perfect circle. Basically it has a 16th of a revolution speed error, hunting. Dont mod your 1210 if you dont know what you're doing, that heavy platter and 'new' bearing will screw up the logic that the speed control uses. So easy to make a mess of things isnt it. |
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Post by jimbo on May 2, 2020 11:42:40 GMT
There would be a simple way of determining the difference for the speed figures for both turntables if the same measuring device was used on both.
Doesn't matter if the device is inaccurate, it will be inaccurate on both.
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Post by rexton on May 2, 2020 11:45:27 GMT
Doesn't matter if the device is inaccurate, it will be inaccurate on both.
That's not strictly true Jim. You need a reference. The Reference is what all else is measured against. This concept is flawed however if the reference device is found to be inaccurate. I would suspect any laboratory worth it's salt wound have accurate testing reference devices.
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Bigman80
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Post by Bigman80 on May 2, 2020 11:53:59 GMT
Doesn't matter if the device is inaccurate, it will be inaccurate on both.
That's not strictly true Jim. You need a reference. The Reference is what all else is measured against. This concept is flawed however if the reference device is found to be inaccurate. I would suspect any laboratory worth it's salt wound have accurate testing reference devices.
Calibration is absolutely essential. You dont know how wrong something is without it. It may not be responsive enough to give a true reading |
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Post by jimbo on May 2, 2020 11:55:06 GMT
You would need a reference for the reference.
Over the years there have been many ways of measuring speed variation in turntables and I bet you all those methods and equipment all measure slightly differently as the technology has improved so has the accuracy.
In the early days things were measured probably by calculation with known constants rather than by specially calibrated equipment that were accurate at that point in time.....until the next piece of technology proved the previous technology to be either flawed or inaccurate or both!
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Post by jimbo on May 2, 2020 11:58:14 GMT
For a laugh heres a 1210 with an GM demod using the analogue productions record. www.flickr.com/photos/59684834@N08/10711325725/in/album-72157629553367709/Yeh its a little octagonal, it should be a perfect circle. Basically it has a 16th of a revolution speed error, hunting. Dont mod your 1210 if you dont know what you're doing, that heavy platter and 'new' bearing will screw up the logic that the speed control uses. What on earth is that? Not what i have seen when a Dr Freikert speed platter app is used to detect a test tone? |
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Post by karma67 on May 2, 2020 12:01:29 GMT
For a laugh heres a 1210 with an GM demod using the analogue productions record. www.flickr.com/photos/59684834@N08/10711325725/in/album-72157629553367709/Yeh its a little octagonal, it should be a perfect circle. Basically it has a 16th of a revolution speed error, hunting. Dont mod your 1210 if you dont know what you're doing, that heavy platter and 'new' bearing will screw up the logic that the speed control uses. hmm perhaps a warning for those that use 5kg's of tenuto mat sat on their platters?? |
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Post by rexton on May 2, 2020 12:13:56 GMT
You would need a reference for the reference. Over the years there have been many ways of measuring speed variation in turntables and I bet you all those methods and equipment all measure slightly differently as the technology has improved so has the accuracy. In the early days things were measured probably by calculation with known constants rather than by specially calibrated equipment that were accurate at that point in time.....until the next piece of technology proved the previous technology to be either flawed or inaccurate or both!
Yep, I think you've just about nailed that!!!! You obviously need a reference, the first is defined and then refined. That's how science works.
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Post by rexton on May 2, 2020 12:15:45 GMT
hmm perhaps a warning for those that use 5kg's of tenuto mat sat on their platters??
Not a problem if you've got an idler and a tachometer.
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Post by macca on May 2, 2020 12:47:58 GMT
Ears are not test equipment. If you could show a difference in measurement on the output then fair enough, you've got something. Otherwise it's just subjective perception which is prone to all sorts of errors. Just knowing that you now have the vibration feet in place will cause you to hear it differently, it's how the brain works.
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Post by rexton on May 2, 2020 12:55:30 GMT
Ears are not test equipment. Yes they are. They perform logical tests for you everyday for example does this sound better than? They are not however a test device with a known reference to measure against for wow, rumble and flutter, which is what we are talking about. |
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Post by dsjr on May 2, 2020 13:32:22 GMT
I'm back just for this - An SP10 and all it's lesser? relatives have but ONE rotating part but are sensitive to what they're mounted in/on. This main bearing, even in the 1210 ancestor 1300/1400/1500 models was incredibly quiet and down at the limits of measurement! i was told back in the 70's that to eliminate effects of feedback, the older models were suspended on cotton threads from the ceiling to measure rumble levels - my first hand experience is that older Technics decks were very feedback prone and that's one area they minimised with the 1210mk2 era onwards. Lenco's may have fairly quiet main bearings (hell, even a bloody Rega can achieve -80db bearing noise!) BUT - and this is something many testers may not realise, all these idler drives have harmonics going up into the midrange (imagine a gentle added soft almost melodic 'ccccchhhhhh' noise [as in 'loch'] way in the background. It's very quiet and not 'rumble' as in 'rumbles and grumbles' but it's still there and it's also there in Garrards and idler Duals of all types, although the 301/401 and lesser models also have a 100hz motor 'drone' added to the mix (high speed induction/synchro-lab style). The Lenco motors (I have four here and worked on others in recent years) run with VERY low vibration and are objects of the art for high speed mass produced induction types, but there's still a usually hard rubber tyre transmitting noise into the platter - in fact, a GL69 with lighter steel platter was quieter through the speakers than a heavy platter G99 I had here. The vertical drive puts practically all the noise out at the edges of the soundstage and it's not always so bothersome there. Lenco's were designed in the mono era, so would have been basically silent as the vertical drive vibrations wouldn't have been audible as the mono cartridges couldn't reproduce them. Lenco's, especialy ones not carved up, are wonderful things and the tonearms significantly better than audio peeps give them credit for (replacing with a bloody LVX or jelco indeed!!!!!). A Facebook concern (Silver Note) does OL stylee tonearms for RB330 price which will drop right in to a Lenco 75/78 arm-mount, using the stock cueing device and everything! Another Facebook chap I've been speaking to, makes new V Blocks of the original shape, so lateral 'play' in the knife-edges is all but eliminated. he also does a mod (not destructive) to the main bearing to allow an oil-bath on a ptfe or similar thrust pad if you so wish (I didn't think the bearing was at all noisy if greased at t'bottom and oiled at the top, but some like to modify these things). Goldring Lenco's, even the base steel platter models, can be very good indeed, but SP10 grade? I've heard a good stock GL75/K9 trounce an Axis/Akito/K9 utterly, so that would put it at or above a typical Rega I'd guess today, as the Rega drives aren't/weren't especially quiet either until you add one of their external power supplies (forget cheaper project decks, they're shite in comparison). I reserve judgement on carved up examples, as a lot of the time I'd say they're not 'done' right - idler retraction links removed and original top plates still used when really, something heavier duty might be better to mount to a solid plinth (see some of the Facebook decks and Lencoheaven too) I've just checked my old HiFi Choices from the late 70's. My SL150/1500 is around lower to mid 70's weighted rumble, the SL1000 model as tested was -77/78db and the SL15 which was an 'economy' version still good quality was in between the two. If Oli wants it I can scan and email. These 'Choice reviews didn't make much of higher motor harmonics in belt and idler drives but as Martin Colloms' reviews often are, one needs to read between the lines sometimes to get what he really means. he always seemed positive on the Technics decks but Lenco idler decks were long gone by then. back in the early 70's, a weighted figure of 60db was classed as good! My Dual 701 direct drive is specced at >70db in terms of rumble - and it certainly ain't from the main bearing!
All academic really as tribalism rears its head yet again. Some will swear by a re-imagined deck based on a Lenco drive (oh yeah, stcked platters too plus a wecord weight) and others more like me perhaps, conditioned to the general superiority of a decent *well sited* direct drive may think differently. properly done, a standard deck is quiet enough and with direct drive/digital style of pitch stability.
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Post by antonio on May 2, 2020 13:45:43 GMT
Technics SP10 unweighted Rumble -50db
Goldring Lenco GL75 Rumble -60db!
Jimbo, you cant just drop this here with no context lol What's the source.... Wow/Flutter Come on man. He just did.  I like jimbo's post, look at the reaction it got. Even DSJR has come back to us, welcome back Dave. |
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Post by jimbo on May 2, 2020 13:47:59 GMT
Just a bit of fun for another Saturday in lockdown!  |
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Post by sq225917 on May 2, 2020 15:38:26 GMT
That round graph is a frequency demodulation of 3.3I test track on a record. If it was perfect it would be a single thick line where the 5 sampled revolutions all overlap perfectly. As deviation from perfect is speed instability.
So a single wobble is likely to be a bit of dirt on the record. A repeating cyclic variation that occurs at the same frequency as the number of motor poles divided by the platter pulley ratio shows the effects of motor clogging.
A deviation that occurs at 2x per revolution shows your record is off centre.
A deviation that occurs at the platter diameter divided by pulley diameter ratio shows a bad pulley or bent shaft.
A deviation at the resonant frequency of the suspension shows you how much that effects the speed.
So with a tiny bit of knowledge of the parts of the deck and their relative sizes you can figure out what's good and bad on the deck and what's ripe for improvement.
It's a killer toolset. But like any tool you need to understand it.
Ie the octagonal 1210 sample graph shows the motor is accelerating the platter 8 times per rev as it tries to hit speed, ie hunting. It's not a clogging artifact as it's a 12 coil motor, so had to be a servo effect.
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Deleted
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Post by Deleted on May 2, 2020 16:14:03 GMT
That round graph is a frequency demodulation of 3.3I test track on a record. If it was perfect it would be a single thick line where the 5 sampled revolutions all overlap perfectly. As deviation from perfect is speed instability. So a single wobble is likely to be a bit of dirt on the record. A repeating cyclic variation that occurs at the same frequency as the number of motor poles divided by the platter pulley ratio shows the effects of motor clogging. A deviation that occurs at 2x per revolution shows your record is off centre. A deviation that occurs at the platter diameter divided by pulley diameter ratio shows a bad pulley or bent shaft. A deviation at the resonant frequency of the suspension shows you how much that effects the speed. So with a tiny bit of knowledge of the parts of the deck and their relative sizes you can figure out what's good and bad on the deck and what's ripe for improvement. It's a killer toolset. But like any tool you need to understand it. Ie the octagonal 1210 sample graph shows the motor is accelerating the platter 8 times per rev as it tries to hit speed, ie hunting. It's not a clogging artifact as it's a 12 coil motor, so had to be a servo effect. Yeah! Hunting! I was going to mention that, but didn't want to possibly offend anyone else. I think I've had me ration for the day. Hunting used to be cited as a direct drive problem, all those years ago - and why the LP12 sounded so much better (!). |
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Bigman80
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Post by Bigman80 on May 2, 2020 16:17:51 GMT
Jimbo, you cant just drop this here with no context lol What's the source.... Wow/Flutter Come on man. He just did. I like jimbo's post, look at the reaction it got. Even DSJR has come back to us, welcome back Dave. I call these posts "Jimbombs" He tosses a grenade and chortles as folk lose their minds over the row that ensues. Hes a troublemaker I tell ya!!! |
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Post by Deleted on May 2, 2020 16:43:20 GMT
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Post by karma67 on May 2, 2020 16:53:24 GMT
yep,i'll just pop down to richer sounds and get one  |
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Post by Deleted on May 2, 2020 16:59:34 GMT
Get me one of these while you're there. The top model.
Sorry. It seems the TX 1000 was the top model, which cost $8000 at the time. The Dragon on the other hand was only $2000:
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Bigman80
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Post by Bigman80 on May 2, 2020 18:46:43 GMT
Get me one of these while you're there. The top model. Sorry. It seems the TX 1000 was the top model, which cost $8000 at the time. The Dragon on the other hand was only $2000: Its beauty isnt it. |
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Post by karma67 on May 3, 2020 9:58:13 GMT
actually i rather like the music its playing too,so ive ordered a copy.
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Bigman80
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Post by Bigman80 on May 3, 2020 10:25:08 GMT
actually i rather like the music its playing too,so ive ordered a copy. What is it? Too lazy too look lol |
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Post by sq225917 on May 3, 2020 11:04:28 GMT
Cant say I thought the quality of the sustain on the piano was really any different, apart from the fact they were using more pedal on the second sample.
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Post by Deleted on May 3, 2020 14:36:09 GMT
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Post by antonio on May 3, 2020 14:48:27 GMT
That's fighting talk Scotty.  |
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Bigman80
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Post by Bigman80 on May 3, 2020 16:32:25 GMT
I’m not sure if the wow & flutter is better or not but what I do know is that my G99 looks a darn sight better than an SP10...... Hasnt April fools passed already? |
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I like jimbo's post, look at the reaction it got. Even DSJR has come back to us, welcome back Dave.
