New Direct Drive Turntable at Purité!

[purite audio]

I am extremely hopeful that we will represent at least one and perhaps two direct drive turntables in the very near future.....
Keith.

[purite audio]

It will come fitted with a 12" Triplanar.
Keith.

[Marco]

Which ones, Keith - GPA Monaco, Brinkmann, or something else? :)

Marco.

[Audioman]

There is a new VPI Classic direct drive but it looks seriously expensive $20K+ and a 3D printed arm $9K.

[purite audio]

Which ones, Keith - GPA Monaco, Brinkmann, or something else? :)

Marco.

Marco Hi, I actually have two direct drives arriving , one as you mentioned is the GPA Monaco with the new 12" Triplanar, you know I like good engineering and the Monaco is full of good design and implementation but there will also be a cheaper DD , I will let you know more when the everything has been finalised.
Did you receive my subs?
Kind regards
Keith

[Marco]

Hi Keith,

Yup, no problem - thanks! :)

The Monaco + Triplanar should be a rather formidable combination :wow:

Marco.

[purite audio]

Thanks Marco.
Re the turntable it should be good, it is based on really sound engineering, Alvin really believes that not only each rotation should be the same , but that each 'slice' within the rotation should be the same.
The motor controls the platter without. touching it , no horizontal contact in the bearing either, it should be super quiet.
KR Keith.

[purite audio]

u tube,

http://www.youtube.com/watch?v=R6oVNmZrSQ4&feature=youtube_gdata_player

[purite audio]

A white paper by designer Alvin Lloyd discussing the design decisions, in the Grand Prix Audio, 'Monaco" turntable.
https://drive.google.com/file/d/0B-hWFR34FK5eNUh1Szg1dmZ4X00/edit?usp=sharing

Keith

[purite audio]

The GPA 'Monaco' is twenty times more accurate than the best belt drive designs and ten times more accurate than the finest direct drive turntables.
Keith.

[The Grand Wazoo]

Can you explain that please Keith? - Do you mean that some errors are a twentieth of those of the best belt drive designs and a tenth of those of the finest direct drive turntables?

[YNWaN]

I believe it refers to the sampling rate of the feedback loop.

I've read the 'white paper' and it is really all about the motor and control - which is fair enough. However, other aspects of turntable design are either skimmed over or ignored (IMO).

However, the Monaco certainly looks to be very thoroughly engineered and nicely made. If I was looking to spend that sort of money I would certainly include it in my 'must hear' list.

[purite audio]

Can you explain that please Keith? - Do you mean that some errors are a twentieth of those of the best belt drive designs and a tenth of those of the finest direct drive turntables?

Chris Hi, the turntables measurements are from page 16 onwards ,and GPA measure the platter itself with cartridge tracking, they dot just measure the motors rotational speed.
The Monao is the most speed accurate turntable available, also no contact between motor and platter.
Keith.

[The Grand Wazoo]

Ah, OK thanks - it's just that '20 times more accurate' is a bit of a definitive statement without qualification!
Thanks Keith.

[purite audio]

Rfom a recent email with the designer Alvin Lloyd,

'The Monaco 1.5 is roughly 20 times
more speed accurate than the best of the belt drives and about 10 times more
speed accurate than the best of the direct drives and probably more like 20
times for most of them also. Believe it or not these are conservative claims
on my part defined by 3 sigma measurements. Especially when you look at an
individual rotation period and slice it into say 5000 pie slices, which is
of course what actually matters, and then looking at the repeatability of
each of those revolutions over a half hour period. Our errors occur in the
5th decimal point .0000X'


Keith

[The Grand Wazoo]

From the way I read that, it would seem that I was correct when I suggested errors are a twentieth of those of the best belt drive designs and a tenth of those of the finest direct drive turntables. This is not the same as twenty/ten times more accurate.

[sq225917]

Keith, looking at at a standard deviation for a full revolution tells you very little about speed stability, it tells you that he has good control of drift, but absolutely nothing about actual wow or flutter. If those are the type of measurements he is basing his speed stability marketing claims on then I'm far from impressed.

My deck spins for five minutes without drifting a single mark on a 360 segment strobe disc. Using his maths that makes my speed stability better than 0.00168% if I extended the period of the measurement there would be an improvement based solely in the increased sample size, which is incorrect.

He's measuring drift, which is self averaging, hes not measuring speed stability which indicates the max positive and negative instantaneous deviation from the selected speed and in the case of wow and flutter looks at low and high speed components.

[purite audio]

Keith, looking at at a standard deviation for a full revolution tells you very little about speed stability, it tells you that he has good control of drift, but absolutely nothing about actual wow or flutter. If those are the type of measurements he is basing his speed stability marketing claims on then I'm far from impressed.

My deck spins for five minutes without drifting a single mark on a 360 segment strobe disc. Using his maths that makes my speed stability better than 0.00168% if I extended the period of the measurement there would be an improvement based solely in the increased sample size, which is incorrect.

He's measuring drift, which is self averaging, hes not measuring speed stability which indicates the max positive and negative instantaneous deviation from the selected speed and in the case of wow and flutter looks at low and high speed components.

Figure one Simon page 19 of the white paper ,measuring within one rotation and 300 continuos rotations!
KR Keith

[Marco]

Simon, whilst you're perfectly entitled to question/challenge the veracity of the technical claims made in relation to the Monaco, please do bear in mind that this is a trade thread.

As long as Keith is happy with the current level of 'interrogation', then I'll allow it to continue.

In that respect, it's up to him to decide when 'enough is enough'. However, when that situation has been reached, I would ask that you leave it there, or otherwise, start a separate thread in Analogue Art, where you can be as critical as you like (within the boundaries of politeness) in relation to this matter - cheers!

Marco.

[purite audio]

Grand prix Audio's background,
http://www.grandprixaudio.com/idx_design_rp.php


Keith.

[MartinT]

Hi Keith

It certainly seems that the Monaco and Dynavector combo gel:
http://www.positive-feedback.com/Issue25/monaco.htm

Have you actually heard this combination in action?

[YNWaN]

Martin, that link you have posted contains some excellent pictures of the Monaco being set up - a 'must see' for anyone interested.

[purite audio]

Martin Hi, thanks again for the link, I have ony ever seen and heard the Monaco once, our example won't be here for a few weeks, Alvin Lloyd knows the Triplanar ,and the tonearms he uses are modified for the Monaco, it seemed sensible to go with an arm that is known.
Alvin is also designing his own arm, he is also trying to change the way vinyl is cut to improve performance, I really don't know that project will bear fruit!
Keith.

[Marco]

Martin, that link you have posted contains some excellent pictures of the Monaco being set up - a 'must see' for anyone interested.

+1. Absolutely awesome. That is proper engineering at its best!

Marco.

[purite audio]

HiFi Plus' review of the Grand Prix Audio 'Monaco' turntable.
http://www.grandprixaudio.com/Roy-Gregorys-Review-of-the-Monaco-Turntable.pdf

Keith.

[MartinT]

Thanks, Keith. That's an excellent review. My only criticism (not of the deck as I've not heard it) is that Roy has got 'servos' and 'hunting' a little muddled in his explanation of the direct drive principle. Early DD decks suffered from hunting but later drive systems used progressive servos which applied proportional correction and didn't hunt.

What is incontrovertible is the precision of the feedback reference in the Monaco (4,700 optical pulses per revolution) which the Technics motor system cannot match (8 teeth in the sensor cog and three sensor coils, so 48 pulses per revolution). I think this is key, and more significant than the exact number of poles in the motor.

I would dearly like to hear one some day.

[purite audio]

Martin Hi, I would very much like you to hear it, Alvin Lloyd ,the Monaco's designer is a big fan of the SP10 he thinks it a remarkable achievement of the period.
As you say technology has moved on, the latest version of the Monaco is even more accurate than the reviewed example.
KR Keith.