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| quote: | Originally posted by DJ RANN
IMO, this whole thing was a marketing fuckup by technics, trying to compete with pioneer against their ever expanding range of CDJ's.
My sources; Me
I'm a technics (amongst other brands) qualified service engineer and used to support myself by repairing and services decks.
Here's how it works, in laymens terms: The old 1200's just usea resistance value based on the position of the pot (slider) which is then sent to the motor control circuit, which in this case is glorified relay turning the resistive value in to a voltage to drive the motor. So basically the resistive value was send to another transformer (via a calibrated internal pot, hence why you can actually make old techincs go to +50 pitch if you really wanted) and it directly sends the voltage to the motor. The problem with this is that as pots degrade (and any one of the other 2 dozen comenets that aloow pitch change to happen in a 1200) the accuracy of the pitch degrades. Even things like temperaute affect resistors and caps
The m5g's take the resistive value of the pot to a fully digital cicruit which effectively constantly calculates the correct voltage to send the motor the motor. Yes, theorectically with any digital control there is always a argument of resoltion or steps in the process, but this is actually more accurate than the resistive error margin of resistors in the all analogue system.
Furthermore, you could not physically move the pitch slider a small enough distance to fall between the resolution steps (you can see the most tiny but relative changes if you hold a ohmeter over the internal calibration pot contacts on a m5g).
Please note I'm using the term resolution steps for no other reason that to give an understandable picture of what I'm trying to explain (the terms is technically incorrect in this instance but you hopefully get what I mean)
What I'm saying is the m5g's are more accurate than any other previous version.
They're still analogue in every way apart from how the motor control voltage is managed. |
That still doesn't sound very sensible to me. I mean, if the signal on the M5G is controlled by a similar pot, which will degrade too, then how will the digital circuit know what the correct signal is if it's being fed a similar degraded signal as on the MK5? From what you're saying I understand that the signal is being converted to a digital one and then that digital signal is used as the control signal. That makes no sense to me, unless the signal is being processed in some way, but I can't understand how it would be processed. Based on what data would they change it?
Also I don't really see how it'd be important to keep the absolute pitch value correct over time. I wouldn't care if the real value would be 3,5% if the slider is at 3,3% or something like that as long as it stays constant and doesn't jump around 3,3% and 3,5% for example.
Does it state anywhere on the digital parts that how many bits it is? From quick calculations i got the maximum resolution for a 16-bit slider for a ±8% pitch slider to be 0,0244140625%, a 24-bit one would have a max resolution of 9,536743164062* 10^-5, but somehow I'm doubtful that Technics would use such a precise slider for the M5G as they used a slider with 0,1% steps for their CDJ, the SL-DZ1200, which was introduced a few years after the M5G, if I'm not mistaken and is twice as expensive too! 
Overall I'd like to know exactly what parts they replaced with digital ones and what exactly the digital ones do and how.
It doesn't make much sense to me to replace the pitch slider with a digital one, which would make the turntable more imprecise, so I doubt they really did that, but I also can't trust it isn't so unless someone can provide some strong facts backed up with good evidence.
edit: Had messed up the calculations, so I corrected them.
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Last edited by skip on Dec-13-2009 at 13:39
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). I wouldn't want the MK2s or the M5Gs though…
