$k area then Re repeatability of a recorded track on a disk-
It is possible but incredibly difficult. Back when i was designing disk drive stuff we had to get a track written on a magnetic disk with something like 100K cycles +/- .1 per turn. It would take as much as 5 minutes of retries to get it written but we could. However we had about 20 lB spinning at 1800 RPM. For a turntable with vinyl it would not happen. The vinyl warp would make it impossible.
It is possible but incredibly difficult. Back when i was designing disk drive stuff we had to get a track written on a magnetic disk with something like 100K cycles +/- .1 per turn. It would take as much as 5 minutes of retries to get it written but we could. However we had about 20 lB spinning at 1800 RPM. For a turntable with vinyl it would not happen. The vinyl warp would make it impossible.
Hi John,
Do you consider this type something already "outdated" ? Have you
developed something that feels more evolved?
Do you consider this type something already "outdated" ? Have you
developed something that feels more evolved?
No, the overhead cam auto engine, along with fuel injection was already designed in this time period of thirty years ago. Is it obsolete yet? '-)
I asked this because we no longer have the Toshiba´s fets ( k146/j73 ) to implement it so I figured you had already developed a circuit with equal or better performance with components accessible to all.
Overhead cams and fuel injection dates back to the turn of the last century , EFI is pretty new going back only 50 yrs ....
😛
Wrong, 😉 ... I've done this exercise a few times - use software upsampling of both recordings to a high enough rate such that a sharp peak, say, can be perfectly aligned - precise to a single interval. Over some period the waveforms will then be perfectly in sync - but it will quickly lose this ideal matching, wow and flutter will kill it every time, the wobble in speed because the record is not perfectly centred on the TT mat is quite easy to see ...
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Components are the missing link, I even requested Toshiba for a custom run of JFETs, but they refused and wrote that even if I would buy millions of each variant they would not do it.
Most names you can find.
Due to that I built my first in 1980 and are now planning a new build..
I have also some heavily modified like the Goldmund Studio.
The only remaining original parts are the platter and the motor.
The PSU was made new sometime in the ´80´s and have two ELNA 100.000uF capacitors plus plus as this was needed to get it working stable, and of course the springs was removed urgently..
There are so many aspects of normal vinyl replay which are ridiculously crude, looked at as a mechanical system. Some really ambitious attempts have been made to to circumvent these, some more successful than others - to do it really properly very well engineered, hence mighty expensive machinery is required ... Laws of Diminishing Returns hold sway, most assuredly ....
Yes pointless, the best SP10-MKIII specs at about ~65us RMS wow and flutter. This is roughly 6 sample periods at 96K RMS or short term peak to peak of 18-20 sample periods. A turntable, arm, cart, and LP system simply is not a precision calibrated instrument.
Try a belt drive, my VPI is rather ludicrus (NOT $90K though) but far above the average and highly rated in its day. Really try it, it's very easy maybe 10min work. Better yet do a mono mix of two passes and put each as one channel in a stereo signal and just listen. Remember a fixed miss in the exact alignment by a couple of samples is one thing (pretty benign) what you get is another.
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You are surprised? Would you call Toyota to go back and make a 1981 Camry just for you?
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Here we go again, build something with what you can get and make up your own mind. Performance in this context is a moving target.
The scheme presented by John is really very elegant and effective in your goal (low noise and excellent quality amplification ). It is very sad that we can not benefit from it without huge efforts.
Look, I am just talking about input stages and their development over the decades. I STILL make them very much like what I have shown. I have access to the parts, and they are not that hard to get, except for large production.
Just because Japanese manufacturers have quit making these devices and most of the American companies are relatively far behind, we can still make quality audio products.
Just because Japanese manufacturers have quit making these devices and most of the American companies are relatively far behind, we can still make quality audio products.
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