Scannermax 506s

[planters]

I am also just about to run a similar test. I had expected that I would find that the 36K would produce the cleaner and sharper graphics, but with more flicker. I thought the 50K were an attempt to see how far the scanners could be pushed with acceptable rounding and miss-tracking. This is exciting, but I don't understand the mechanism.

[Pangolin]

The situation has to do with the difference between "small signal performance" and "large signal performance" (which, for you guys, can roughly be translated as "small details" and "large angle movements"). Large signal performance is strictly limited by the maximum amount of PEAK current that a driver can put out, which is itself limited by the drive (i.e. supply) voltage, scanner coil resistance, and amplifier dynamics. Small signal performance is limited by gains inside the servo driver, and also limited by this thing I've referred to in the past called an "error compressor".

What literally all moving magnet scanners do is employ a kind of "Trick" in the servo, to get better performance. But the trick only works for small signals (i.e. how much we can compress the error signal, and how much we can increase the gains inside the servo). What this means is that LARGE SIGNAL PERFORMANCE REMAINS THE SAME (or should remain the same) regardless of tuning. And what THIS means is that for large projected patterns, for large beam effects, etc. Norty's 36K scanners *should* do exactly the same job as Norty's 50K scanners. The difference is in "small signal" (i.e. small detail) performance.

When tuning the same scanners faster and faster, one must understand that large moves do not get any faster -- only the small moves do. This means that there is a larger and larger dichotomy between small-signal performance and large-signal performance -- which in turn means that certain images will change as you zoom them in and zoom them out.

For example, take text, or certain graphics with a lot of small details (imagine a person's face where the eyes and eye-brows have a lot of small lines). When projected at a normal angle, all of the details are small. But if you then try to "zoom through" these images, what was once small becomes large. It is likely that these small details will become rounded or even completely tear apart when they get large. So you'd have to do two things: 1) favor a lower overall scanning speed; or 2) slow down the scan rate as you make images with small details larger.

Lightspeed really favored fast (for small-signals) tuning, and did manual work (i.e. placed additional points, or simply slowed down the scanning) to manage the difference between small details and large details. For sure you come out ahead this way. But it requires more cognizance. It's like having a manual-speed transmission with more gears. You have to a) know how to shift; and b) enjoy shifting gears.

So for people who are not all that excited about shifting gears (including me by the way) or people who are not really technically astute to understand the differences or when or how to recognize them (and what to do next), a lower tuning is better -- only because there is a smaller difference between large and small signal performance. (Remember, large stays the same, only small gets faster.) So for certain customers I absolutely recommend a lower tuning. It will just be a more enjoyable experience (like for many -- including me, an automatic transmission is a more enjoyable experience).

In the case of both Norty and Planters, both of these guys are clearly technically astute and so that is not a problem. The only question is -- will they enjoy switching gears more often (and a related question -- will the things that they are projecting really require them to switch gears more often). So because I can't answer that question, I like to supply both and simply say "you tell me which one you like better".

In the case of both Norty and Planters, this must be done with separate scanner amps. But with digital scanners, I can simply supply files "here is a 30K file, a 40K file, a 50K file, a 60K file, etc." so digital makes it a lot easier!

Bill

[mixedgas]

The amps for Planter's system are ones from my import session. They went to Bill for modification. I'm waiting to hear from Bill today on the change of a diode that does the compression. Bill mentioned 50K but he did not say at what angle in the last email. Bill is really tweeking this amp.

Steve

[Pangolin]

I am also just about to run a similar test. I had expected that I would find that the 36K would produce the cleaner and sharper graphics

For sure 50K *should* produce cleaner and sharper graphics -- at least when the details within those graphics are small.

I thought the 50K were an attempt to see how far the scanners could be pushed with acceptable rounding and miss-tracking.

The only thing that *should* round or mis-track is larger-area portions of graphics when you are trying to make them scan very quickly. This can be seen in the grid pattern in this video that I made for Norty a while back at around 2 minutes into the video.
https://www.youtube.com/watch?v=gImSsPJCxw4

When the grid pattern gets projected very large, the outer portion will begin to round. Everybody will see this in every scanner. It is only a matter of a) the scan angle when this happens and b) the scan speed at which this happens.

This place of rounding will happen at very nearly the same point (same scan speed and angle) on both your 36K-tuned and 50K-tuned amps.

By the way, as I mentioned in my email to you, I did notice some ringing on the Y axis of the scanners I shipped you Planters. I know what's going on and how to solve it, but wanted to get the scanners into your hands to get your "big picture" feedback. Plus I was going out of town, and so it was more valuable to me to get your feedback while I was out of town, rather than wait for me to return, make changes, and then ship. This ringing is entirely solvable (and not present on the large-mirror set I shipped to Norty) and was only seen on certain patterns and at certain scan rates (only when the input sample rate actually excites the ringing). So we'll see if you even notice it.

Bill

[planters]

Thanks Bill. That was clear and useful.

[swamidog]

bill -

this was very helpful. thank you.

The situation has to do with the difference between "small signal performance" and "large signal performance" (which, for you guys, can roughly be translated as "small details" and "large angle movements"). Large signal performance is strictly limited by the maximum amount of PEAK current that a driver can put out, which is itself limited by the drive (i.e. supply) voltage, scanner coil resistance, and amplifier dynamics. Small signal performance is limited by gains inside the servo driver, and also limited by this thing I've referred to in the past called an "error compressor".

What literally all moving magnet scanners do is employ a kind of "Trick" in the servo, to get better performance. But the trick only works for small signals (i.e. how much we can compress the error signal, and how much we can increase the gains inside the servo). What this means is that LARGE SIGNAL PERFORMANCE REMAINS THE SAME (or should remain the same) regardless of tuning. And what THIS means is that for large projected patterns, for large beam effects, etc. Norty's 36K scanners *should* do exactly the same job as Norty's 50K scanners. The difference is in "small signal" (i.e. small detail) performance.

When tuning the same scanners faster and faster, one must understand that large moves do not get any faster -- only the small moves do. This means that there is a larger and larger dichotomy between small-signal performance and large-signal performance -- which in turn means that certain images will change as you zoom them in and zoom them out.

For example, take text, or certain graphics with a lot of small details (imagine a person's face where the eyes and eye-brows have a lot of small lines). When projected at a normal angle, all of the details are small. But if you then try to "zoom through" these images, what was once small becomes large. It is likely that these small details will become rounded or even completely tear apart when they get large. So you'd have to do two things: 1) favor a lower overall scanning speed; or 2) slow down the scan rate as you make images with small details larger.

Lightspeed really favored fast (for small-signals) tuning, and did manual work (i.e. placed additional points, or simply slowed down the scanning) to manage the difference between small details and large details. For sure you come out ahead this way. But it requires more cognizance. It's like having a manual-speed transmission with more gears. You have to a) know how to shift; and b) enjoy shifting gears.

So for people who are not all that excited about shifting gears (including me by the way) or people who are not really technically astute to understand the differences or when or how to recognize them (and what to do next), a lower tuning is better -- only because there is a smaller difference between large and small signal performance. (Remember, large stays the same, only small gets faster.) So for certain customers I absolutely recommend a lower tuning. It will just be a more enjoyable experience (like for many -- including me, an automatic transmission is a more enjoyable experience).

In the case of both Norty and Planters, both of these guys are clearly technically astute and so that is not a problem. The only question is -- will they enjoy switching gears more often (and a related question -- will the things that they are projecting really require them to switch gears more often). So because I can't answer that question, I like to supply both and simply say "you tell me which one you like better".

In the case of both Norty and Planters, this must be done with separate scanner amps. But with digital scanners, I can simply supply files "here is a 30K file, a 40K file, a 50K file, a 60K file, etc." so digital makes it a lot easier!

Bill

[planters]

It's not all that mystical. I'm always thinking about shrimp although less often about plates, but there you go.

[swamidog]

It's not all that mystical. I'm always thinking about shrimp although less often about plates, but there you go.

[kecked]

I echo that. That was very helpful. I'm loving 506 scanners. They kick butt. They kick the a$$ out of 6800HPs in such a small space and with bigger beams. Very impressed. Now we need your drivers. If the saturns are anything like the 506s in comparison they should also match or pass on by the 6215s with less heat in a smaller package. I suspect after reading the above post it won't make much of a difference for 30k material and I don't think I've ever seen any 60k material around. Messed with it myself and frankly I didn't see a lot of advantage accept for sloppy unoptimized art from a 3d program. These scanners are wonderful.

[Pangolin]

Post some pics once you get your little projector finished Marc!