Which scanners

[Frixxion]

FRixxion,

I have some complete used sets of ct6800 with amps, cables power supply etc.., make me an offer in euro by PM.

I think they fall way out of my budget, my budget is 300 euro's MAX

[Frixxion]

Thanks everyone for all the help! I have been getting some offers on scanners and right now I have the choice between these 3:

- 2nd hand Scanpro40
- 2nd hand DT-40
- new DT-25

I know the scanpro40 and DT-40PRO's are a whole different level of performance then the DT-25, but the DT25's are the cheapest and it would save me alot of money if I would go for those. But on the other hand if I just chip in a bit more money I'll be on a completely different level of performance .

So let's just say I have enough money and I have to choose between the DT-40PRO's and the SCANRPO40's. Which would suite my needs the best. Remember I'm aiming for doing beamshows with (if possible) alot of bounce mirrors.

[buffo]

If I am not mistaken this is called the Resonant frequency.

Resonant frequency is something else, and it's not something you ever want to reach in a standard closed-loop scanner. (Bad things can happen!) There *are* some special-purpose scanners that are designed to operate at their resonant frequency, but they are not suitable for laser shows.

However, even the resonant frequency is not as high as the PPS speed. PPS is more of a tuning standard than anything else. It's one way to compare different scanners, based on a single test pattern, but it's really a very nebulous way to specify performance. It's perhaps not the best way to do it, but it's what the industry has adopted, so we're stuck with it.

Still, the botton line is that the actual frequency response is nothing close to the PPS speed.

Step Responce time I think is more related to pps.

Related, yes. And depending on the size of the "step", it could be very close to the PPS speed. But this is a term that normally applies to stepper motors (which usually have a fixed step width), rather than galvos (which do not).

Frixxion:

As for which galvos to buy - if you are on a budget then you have to work within that limit, and we all understand that. (I'm on a tight budget myself!) If you want to run mostly graphics shows, you'll want to run at 30K, and that precludes slower scanners. (Though, admittedly, the DT-25's are very close... In a pinch, they'll do.) Beam shows, on the other hand, will look just fine even at 20K.

I normally suggest buying the faster scanners anyway though - for the simple fact that if you run a fast scanner at a slower speed, you'll get a wider scan angle. (Of course, you have to re-tune them at that slower speed, but that's not all that hard to do.)

The DT-40's or the Scan Pro 30's will work just fine for both beams and graphics. If you decide to get the DT-40's, I'd re-tune them for 30K to get a wider scan angle though.

Adam

[dave]

- ScanPro30s are fast but tend to drift a lot.

We have sold a lot of these, as well as having many sets in some of our hire projectors.. This is the first time I have heard anyone mention this.. I would love to hear why you are saying they drift, cause in my experience they don't..

[dave]

t the DT25's are the cheapest and it would save me alot of money if I would go for those.

Keep in mind most show content is optimized for 30k.

[edit] opps Adam already said this

[Frixxion]

Ok, I've decided I'll chip in a bit more. This means I have the choice between DT40pro's or Scanpro40's. Buffo said in his review about the scanpro40's that they are way better, but I haven't read about anyone else saying this (don't take it personal Buffo!). And that review was made almost a year ago. So are there more peopele who think this?

[heroic]

We have sold a lot of these, as well as having many sets in some of our hire projectors.. This is the first time I have heard anyone mention this.. I would love to hear why you are saying they drift, cause in my experience they don't..

Well, to take an example, I set up my projector with targetted beams intending to hit certain optical elements mounted on rafters, got them all lined up, scanned them for ten minutes and by the end of the ten minutes they weren't lined up any more. I left the projector to warm up for an hour or so, redid the alignment, and all was fine until the temperature in the room changed and that messed it up again. The temperature inside my projector is not very stable (it's an ultra-compact design, especially given that it's RGB) and I think this contributes to the problem.

I bought my ScanPros from you, Dave, and while they were awesomely tuned and all, the amps seem to be a little temperature dependent. I think this is inherent in the design.

-J.

[colouredmirrorball]

Recently I saw a genius guy with an 8 Watt Argon laser solve this problem. He used shutters with mirrors/dichro's attached to them. Before the show he placed mirrors and diffraction gratings around the place and pointed the mirrors on the shutters to the effects. The shutters were MIDI-controlled and all I can say was... Whoaw...
I met the guy and gave him the adress of this website. Maybe he joins us, once...

[buffo]

Ok, I've decided I'll chip in a bit more. This means I have the choice between DT40pro's or Scanpro40's. Buffo said in his review about the scanpro40's that they are way better, but I haven't read about anyone else saying this (don't take it personal Buffo!).

No offense taken dude! There's absolutely no shame in asking for other opinions. But I have run the DT-40's and the ScanPro 40's side-by-side, and I do think that the ScanPro's are the better of the two.

Still, it's always a good idea to get more input from others.

Heroic;

The ScanPro amps have changed recently (within the last year or so). Is it possible that you had an earlier version? I've never experienced the drift you described, although I didn't run the ScanPro30's for very long. (Only played with them for a week or two while I was doing the review, and that was several years ago.) I'm running the ScanPro 50's now (tuned to 30K), and I love them. Rock solid, no drift, and *awesome* mirrors. Plus they scan about 5 degrees wider than the DT-40's at the same speed.

Adam

[heroic]

The ScanPro amps have changed recently (within the last year or so). Is it possible that you had an earlier version? I've never experienced the drift you described, although I didn't run the ScanPro30's for very long.

It's possible I guess. They are great scanners, but I have to say, I've been blown away by the performance of the CT6800s.

-J.