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Direct Drive Turntables and 'Hunting'

P

pete the bus

pfm Member
Having owned and thoroughly enjoyed using a 1970's Japanese DD turntable for the last year or so I am curious to know why they had such an awful press at the time. I know there was the 'flat-earth', Linn/Naim, British is Best attitude around, but it didn't stop other Japanese products from breaking into the 'Best-Buy' pages.
Hence I am wondering if the phenomenon of 'Hunting' was presumed to be the curse of all (Japanese) Direct Drive platters, and therefore not even considered for testing?
I must admit my table sounds fine to me, but I am curious to know how hunting is measured and what it's sonic effects are.
(Incidentally, the W&F is quoted as 0.04% WRMS)

Any thoughts?.
 
pete the bus said:
Having owned and thoroughly enjoyed using a 1970's Japanese DD turntable for the last year or so I am curious to know why they had such an awful press at the time. I know there was the 'flat-earth', Linn/Naim, British is Best attitude around, but it didn't stop other Japanese products from breaking into the 'Best-Buy' pages.
Hence I am wondering if the phenomenon of 'Hunting' was presumed to be the curse of all (Japanese) Direct Drive platters, and therefore not even considered for testing?
I must admit my table sounds fine to me, but I am curious to know how hunting is measured and what it's sonic effects are.
(Incidentally, the W&F is quoted as 0.04% WRMS)

Any thoughts?.
Click to expand...

I'm interested to know what hunting means. It's not a term I have heard of before in relation to a turntable.

I have had a DD deck before, it was a hitachi with an sme 3009 on it, a huge bloody thing. It was a solid deck and ran pretty silent but was trounced by a rega planar3 in terms of musicality, I enjoyed the rega way more despite notable flaws that were not present in the hitachi.
 
linnfomaniac83 said:
I'm interested to know what hunting means. It's not a term I have heard of before in relation to a turntable.
Click to expand...

It relates to servo control. The theory being that the deck is never rotating it's platter at a constant speed, but very quickly and continually correcting between the two states of 'slightly too fast' and 'slightly too slow'. I suspect it was more of an issue on cheaper decks with light platters than the high-end / pro decks where rotational mass should smooth things out. It was also a term that dated from the time where UK belt drive decks had almost absolute market / press dominance so may have more than a degree of FUD to it!
 
Tony L said:
It relates to servo control, the theory being that it's never actually rotating at a constant speed, but very quickly correcting between 'too fast' and 'too slow'. I suspect it was more of an issue on cheaper decks with light platters than the high-end / pro decks where rotational mass should smooth things out. It was also a term that dated from the time where UK belt drive decks had almost absolute market / press dominance so may have more than a degree of FUD to it!
Click to expand...

Yep, speed stability is an area where the hitachi kicked the rega into the weeds so it sounds like there was more than a degree of FUD.

The hitachi was very stable and silent running but it couldn't boogie like a rega.
 
I have used a servo-controlled Sony belt drive (TTS3000) as well as DD TTs from technics and JBE and have not heard the dreaded "hunting" speed problems.

Could the whole issue be nothing more than negative publicity created in the "flat Earth" mind?
 
It's worth noting that many Jap direct drives, especially from the seventies, did not have servo control.

The Pioneer PL 71 is in this category, and has a very simple PSU devoid of electronics.

Less to go wrong, and possibly a factor in its perfromance.
 
Rusty, where did you get your information from regarding the PL-71? The manual (available on vinyl engine), clearly states it has a servo controlled motor.
 
The PL71 has servo control but not quartz locking (I owned one for 30+ years).

It was the quartz locked machines that were accused of hunting but I have never heard it on my SL10.

Perhaps the earlier ones did but more than likely just marketing BS in support of belt drives made by people without the heavy duty tech needed to implement a DD.

Having said that, I now have BD.

Steve
 
hifi_dave said:
'Cogging' is the term I have heard for this condition.
Click to expand...

Yes, cogging. Maybe that's what I'm referring to and not hunting? But, cogging or hunting, was it really that much of an issue with direct drive tables? And how is it measured and what are its sonic effects?
I have never seen any reference to cogging/hunting when looking at DD specs.
Would it show up in the W&F figures?
 
hifi_dave said:
'Cogging' is the term I have heard for this condition.
Click to expand...

That's a different one, that's the platter 'stepping' between the poles of the motor, e.g. an eight pole motor would have eight kind of 'bumps' each rotation. Again a degree of FUD is to be assumed here!

PS I suspect some real answers to all this will be found in Paul R's turntable speed analysis thread in the DIY room as there are results for many decks of all drive types.
 
I think the reputation comes from the deluge of budget DDs that came to market during the 70s and 80s. Most of these were of lightweight build and didn't work too well.
Direct drive was the thing to have, so it was offered at progressively lower cost but quality naturally suffered.

I wouldn't worry at all with something of decent quality build.
 
pete the bus said:
Having owned and thoroughly enjoyed using a 1970's Japanese DD turntable for the last year or so I am curious to know why they had such an awful press at the time.
Click to expand...

Because the UK hi-fi press was in thrall to flat earth nonsense and had no interest in how things really performed, much preferring a simple story which basically said Japanese hi-fi=bad, British hi-fi=good, despite all the evidence to the contrary. They managed to fool a lot of people too, for a while.
 
pete the bus said:
Rusty, where did you get your information from regarding the PL-71? The manual (available on vinyl engine), clearly states it has a servo controlled motor.
Click to expand...


You're right and I'm confused. I was thinking of Quartz-locking, or rather lack thereof.
 
muzzer said:
Does the legendary teccy 1210 suffer from this?
Click to expand...

Do ANY DD's of reasonable quality suffer from this? That is what I'm trying to establish. Are there measurements to show the effects, and are there audible consequences?

Opinion seems to be angling towards a 'conspiracy' of FUD!
 
pete the bus said:
Do ANY DD's of reasonable quality suffer from this? That is what I'm trying to establish. Are there measurements to show the effects, and are there audible consequences?

Opinion seems to be angling towards a 'conspiracy' of FUD!
Click to expand...

It's not quite a FUD conspiracy.

From what I remember, the problems levelled at early DDs were largely down to a combination of using tachometer servos (instead of quartz lock servo systems) and lightweight platters. The servo cannot react fast enough to cope with dynamic change in musical programme, and the platter doesn't have enough mass for flywheel effects to overcome the problem. This wasn't the sort of thing that came up on standard W&F tests because a 3kHz test tone is dealt with exceptionally well by frequency generator servos. Under dynamic conditions, the friction from stylus drag was enough to cause slowing under load.

Of course, by the time we got PLL servos, this became one big non-issue, except for the cheapest, nastiest DDs. But by then, the damage had been done. "Slowing under load" became the knee-jerk dismissal of DD turntable, irrespective of whether they actually did it or not, and DD turntables were considered a no-no.

In fairness, many of Martin Colloms turntable tests group in HFC of the late 1970s and early 1980s found DD decks often outperformed BD turntables, but by that time the whole flat earth thing had pretty much taken hold and to say something was better than the LP12 was to invite people to question your hearing and your sanity.
 
Alan Sircom said:
"Slowing under load" became the knee-jerk dismissal of DD turntable, irrespective of whether they actually did it or not, and DD turntables were considered a no-no.

In fairness, many of Martin Colloms turntable tests group in HFC of the late 1970s and early 1980s found DD decks often outperformed BD turntables, but by that time the whole flat earth thing had pretty much taken hold and to say something was better than the LP12 was to invite people to question your hearing and your sanity.
Click to expand...

That seems to sum it up nicely. I must admit to being a 'belt drive is king' believer at the time (mainly because of the mags). I can now look at Japanese DD tables with a whole lot more admiration than I used to do!
 
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