worthwhile spending the extra $2 on pololu 4988 black?

Some of the problems people report with their steppers make me think that the standard pololu drivers might be close to their limit. I'm wondering if there is a compelling argument for going with the black edition driver. The description makes it seem much more robust, and the additional $2 per driver seems a trivial difference in price. I think I might just go with them, but I was trying to see what peoples experiences were.

I think most people looking for more juice are going with DRV8825-based Pololus now. They might require minor modifications to the electronics, though, as Reset no longer has an internal pullup.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

I got a Black edition pololu a few months ago. I had blown my Z axis controller and it seemed like a good idea as a replacement. The difference is minimal, to be honest. The absolute maximum amperage is the same, and the maximum un-cooled amperage is not all that much more. The 20% difference is nice if you're right on the edge of being able to use the stepper without cooling, but if you're running the steppers really hot you need a fan and heat sink either way. I think you might be better off spending another $2 on the DRV8825, which can do 1.5 A/2.2A with cooling and has smaller microstepping (which means smoother and quieter motion). I'll be making that switch soon, hopefully.

the 8825's look nice, but as Traumflug has pointed out they require changes to the electronics. How are you going to accommodate that?

I guess the minimal difference between the green and blach 4988's is all that I can expect for such a minimal difference in cost.. On my existing Prusa derivative, I am able to use the green 4988's without issue and without the need to cool. I'm in the process of building a kossel derivative, and was going to use the black drivers there.

Actually, Pololu was kinda clever with this. The initial version (it's still listed on their site as [www.pololu.com] for a dollar cheaper) required the pullup to RESET. However, if you check out the current version [www.pololu.com] under the section "Control Inputs" they explain that they made an update to make it closer in functionality to the A4988. Basically what was VDD on the A4988 is now FAULT on DRV8825, and they added a 10k resistor between FAULT and SLEEP. This means if you put 5V (or 3.3V) on FAULT as if it were an A4988 it acts as a pullup for SLEEP to imitate the A4988, and afaik most electronics packages tie SLEEP to RESET so that they're both pulled up. If you check out [forums.reprap.org] Misan shows how you can add a resistor to pull up on the older (cheaper) style ones, and a few other people mention out-of-the-box success with the newer release.

There is a new edition of the DRV8825 Pololu which fixes the sleep/reset issue, it's also the most expensive, although still only $13.95. Having wasted a lot of time with dodgy stepsticks I would say it is worth spending the extra $4 for drivers that are dependable.

If you want to save a buck buy up some of the old version DRV8825s and some 5c resistors.

I just checked out their web site, and indeed it seems as if the newer DRV8825 ought to drop right in. The only change I think I see is that the jumpers need to be changed. I am currently running my 4988's with all 3 jumpers in place giving me 1/16 microstepping. If I leave this configuration in place with the DRV8825, I get 1/32 microstepping. It looks like the first two jumpers would need to be removed (or perhaps the axes would need to be recalibrated - doubling the steps/mm in all cases????)

Yes, doubling the steps/mm would be required (or changing jumpers). I was looking for this earlier, and I finally found it: someone from my local hackerspace made a short video about them: [www.youtube.com]. The higher microstepping means (among other things) quieter motion.

I guess that decides it for me. I'm going to be ordering the drv8825's.