DM15L Review

[syzygetic]

Ok, so I am a long time 12C user, and for scientific calculators, I've always used something larger, like a TI89 or a computer itself (honestly mostly the computer).

I have always found the large screen super powerful graphing calculators a bit awkward compared to a computer. Once you exceed the capabilities of, say, an HP42 or a 15C, you really might want to simply move to a computer, since the functionality is far greater (at least more open ended), and you can transition complex calculations into programs seamlessly using modern languages. I know plenty of people disagree, but for me, calculators are essential up to the power of about a 15C (or 12C if you're only doing business work), and then it's a quick break for a laptop or a server instead.

Anyway, so I got a DM15L (Serial 21020) because I've always wished I had a 15C for non business calculations, and, let's be honest, a Voyager is way classier than a TI89 for scientific work that isn't graphing or heavy programming (see above about computers and this being 2022).

My calculator is always on my desk, always ready for a fast computation, doesn't require knowing whatever key command the on-screen calc might be in today's OS du jour (I switch up a lot). My calculator is also far more tactile for fast entry of lists of numbers without looking.

So far, the things I love about the DM15:
- The fonts. I love the squarish font, particularly, it's so much more visible and stylish than the multisegment display as is traditional. The fonts alone are nearly worth the price difference between, say, a current production 12C, which is better built, and a current DM12L, which would have these fonts.
- The caseback. Metal is what the HP ones should have been, given their generally high build quality.
- The legends and printing on the overlay & keycaps. Top notch, clearer even than the HP original on my 12C.
- All functions I have tested work as expected. This is a powerful and intuitive calculator... an emulation of the original, of course, so no surprise there, but there's no doubt that the thing works.
- The slipcase. It's just simple, and nice, and works!
- The price. I actually think the price is fair for a low production device which can't possibly have an enormous audience.

The things I don't love about the DM15:
- The case front. Mating plastic to the metal accurately had to be hard, and it creates a two-color two-texture effect. The metal is far more tactile, and the case should have been all metal, in my opinion, even if it would have meant switching up the assembly and making the back a plate on a unibody or something.
- The keyboard. It's just not as good as my 12C. I get missed keys sometimes, variable key press strengths required, and, despite being very hard to operate, it's not actually as tactile as my lighter-operation 12C. Keyboards are hard, being a combination of the physical build and the software interpreters, but this one needs some work.
- The flex when typing. Maybe because I have to press so much harder to make some of the keys work on this unit, but the display can be seen to flex a bit when I press some keys. This doesn't happen on the 12C.
- The screen isn't quite aligned with the top of the opening on the bezel around it. It's just ever so slightly lower on the left hand side than on the right hand side, but... enough to see. This isn't a screen issue, it's a bezel issue... the bezel is just barely higher on the left side than on the right side.
- There's a circular smudge in the metal finish (not chemical, but mechanical) near where the logo is applied on the brushed bezel.
- Mini USB? In 2022? Heck, even in 2015? Today, USBC or bust, but I guess I'd take Micro USB, maybe. I think the DM42 has Micro USB, so perhaps they fixed this.
- Mine came with firmware V27. This is pretty old by now, I do wish they'd at least deliver flashed ones. Easy enough to flash.

All in all, I would buy this calculator again, I am a happy customer. SwissMicros is on the right path, and I might even buy their WP43 when that model comes out, but I do hope they update the keyboards and consider being less concerned with historical accuracy on the finishes in favor of better tolerances and build quality. If the DM15L were a metal unibody with a plate back, almost all my nitpicks would be avoided.

[harryp]

I've been on the fence for a while on the DM15L. I've been waiting to see what this 'mystery' calculator is that they were working on before deciding. But your review is straightforward and fair and I can see that, a few defects noted, the product is worth buying. Thanks.

[Dave Britten]

For what it's worth, I have a DM41L and DM16L, and haven't had any significant problems with the keys. Yes, they take a little bit more force than an actual Voyager, but I haven't had problems with missed keystrokes or the case flexing. I did have key registration issues when I tried running the calculators at low speed (12 MHz?) but they're fine at full speed.

Despite owning two 15Cs and a 15C LE, I'm quite tempted to buy a DM15L just to have a faster 15C with more memory.

[syzygetic]

(02-17-2022 12:57 AM)harryp Wrote:  I've been on the fence for a while on the DM15L. I've been waiting to see what this 'mystery' calculator is that they were working on before deciding. But your review is straightforward and fair and I can see that, a few defects noted, the product is worth buying. Thanks.

Absolutely, this is how I would characterize the product. I wanted to wait for their mystery product too, and maybe I'll buy it one day, but this product works and is fairly priced, so I'm happy in the meantime.

[johanw]

I have both a DM15L and a HP12C, and to my surprise I liked the feel of the DM keyboard more than the HP one. The look of the curved HP keys is far better though.

But the price difference was too much to get a DM12L for me. That HP costed me $40, thee DM12L costs almost 3 times that much.

The DM15L keyboard feels IMO also much better than that of the DM42 I have (a later model with the improved keyboard).

[Dave Britten]

(02-20-2022 11:02 AM)johanw Wrote:  I have both a DM15L and a HP12C, and to my surprise I liked the feel of the DM keyboard more than the HP one. The look of the curved HP keys is far better though.

But the price difference was too much to get a DM12L for me. That HP costed me $40, thee DM12L costs almost 3 times that much.

The DM15L keyboard feels IMO also much better than that of the DM42 I have (a later model with the improved keyboard).

I've noticed there's a pretty wide variety in the feel of original Voyager keyboards. The Chinese 1xCR2032 models from around 15 years ago have a very crisp feel that's actually rather pleasant. I've also got a couple that have very short and kind of mushy travel, especially the ENTER key. They all respond just fine, though (except for the 15C LE with its dodgy key contacts).

[Garry Lancaster]

I've owned a DM16L for a couple of years now and have found the keyboard very nice to use on the whole.

The only issue has been the ON button which, over time, has seemed to sink lower and lower. It's now slightly below the level of the faceplate in one corner and is consequently somewhat awkward to activate.

[syzygetic]

Update: flashed to v32 this morning, no issues at all, easy process. Heck, I even like their serial console, though I don't have much use for it, since I'm not developing the thing, just enjoying a quality calculator.

In the end, having used this daily for a couple weeks now, I can confidently say that:

1. I'm glad I bought this, it's a fine calculator. I would recommend others looking for a 15C today buy this instead of buying something old or something insanely expensive (like the 15C LEs you see out there).
2. The keyboard needs some work. My current 12C daily at home, a 25th anniversary LE model, is just leaps and bounds better feeling and more reliable when working by touch alone.

[OlidaBel]

Also happy with the DM15L.
Some comments :
- I like the pouch
- I like using DM15L too
- the latest firmware allows to position the 'RAD', 'F' and 'G' annonciators above the numbers, good.
- LCD is not the best : there is a visible shadow under the segments.
- With the 15 model, contrary to the 11 one, there is the famous "HP15C simulator" application, it's a must have : usb connection, backup, writing, testing, documenting. You can dive into complicated personal programs creation, knowing there will always be a copy of your work on disk. Try to do the same with the original...
https://hp-15c.homepage.t-online.de/content_web.htm

[johanw]

(02-20-2022 01:16 PM)Dave Britten Wrote:  I've noticed there's a pretty wide variety in the feel of original Voyager keyboards. The Chinese 1xCR2032 models from around 15 years ago have a very crisp feel that's actually rather pleasant. I've also got a couple that have very short and kind of mushy travel, especially the ENTER key. They all respond just fine, though (except for the 15C LE with its dodgy key contacts).

I have a HP12C model with 3 small batteries, and indeed the very short travel distance of the enter key is the most irritating of the keyboard IMO. You also have to press it at the top or it won't travel at all.

[Commie]

Hi,

Very interesting, how does the dm15l compare to the hp15ce?. I bought the latter and it suffers from key bounce, other than that it seems a faithful reproduction of the original.

Cheers
Darren

[Steve Simpkin]

(10-17-2024 05:35 PM)Commie Wrote:  Hi,

Very interesting, how does the dm15l compare to the hp15ce?. I bought the latter and it suffers from key bounce, other than that it seems a faithful reproduction of the original.

Cheers
Darren

Have you tried updating the firmware on your HP-15C Collector's Edition? The updated HP-15C CE firmware fixes the HP-16C emulation DEC display bug and increases key debouncing time (to 120ms). Increasing the key debouncing time mostly helps with cases where one key press produces multiple presses for example getting 1223 on the display when pressing 123).

Here is the official announcement. If you look through this long post, you will see several cases where the new firmware fixes the above multiple entry key press issue.
https://www.hpmuseum.org/forum/thread-22...ght=bounce

You will need the USB programming cable to upgrade the firmware.
https://www.thecalculatorstore.com/p/dat...alculators

The USB cable also allows you to use a Windows utility program allows you to backup and restore the memory of your HP-15C CE to a file.

[AnnoyedOne]

(10-17-2024 05:35 PM)Commie Wrote:  ....how does the dm15l compare to the hp15ce?

I seriously considered the Swissmicros DM15L but then saw the HP-15C CE announcement.

IMHO the two are very similar. Both allow memory save/restore via USB and there's software for both to list programs in those dumps.

The difference, IMO, is a classic 7-segment LCD (HP-15C CE) vs alphanumeric (DM15L).

My CE has no key bounce issues.

A1

[Commie]

Hi Steve and all,

Thanks for the heads up, I've had a quick flit through the info/links given, looks interesting, something to come back to in the very near future. Thanks again.

Cheers
Darren

[rprosperi]

(10-17-2024 05:50 PM)AnnoyedOne Wrote:  

(10-17-2024 05:35 PM)Commie Wrote:  ....how does the dm15l compare to the hp15ce?

I seriously considered the Swissmicros DM15L but then saw the HP-15C CE announcement.

IMHO the two are very similar. Both allow memory save/restore via USB and there's software for both to list programs in those dumps.

The difference, IMO, is a classic 7-segment LCD (HP-15C CE) vs alphanumeric (DM15L).

My CE has no key bounce issues.

A1

The 15L actually has a variety of fonts to choose from, including several 7-segment like fonts, in varying weights, so you can have a Voyager like display if that's preferred. The new 2-line display mode will have fewer font options as they don't all scale down well.

[dm319]

(02-20-2022 01:16 PM)Dave Britten Wrote:  I've noticed there's a pretty wide variety in the feel of original Voyager keyboards. The Chinese 1xCR2032 models from around 15 years ago have a very crisp feel that's actually rather pleasant. I've also got a couple that have very short and kind of mushy travel, especially the ENTER key. They all respond just fine, though (except for the 15C LE with its dodgy key contacts).

My HP-12c platinum is really not a nice a keyboard - it has a good tactile feel to it, but sadly that doesn't have anything to do with the key actually registering. Combined with some keys needing a hard press and others less so, it is a really confidence-uninspiring experience. My Hp-12c Rogue is much nicer, and needs a much lighter touch - i.e. enough of a press to get the tactile feel, but it still occasionally misses ones.

My DM-42 is the most confidence-inspiring. It's a later edition one, and if I hear the click I am 100% sure the key press has happened.

I'm planning on getting a DM-15L for my 10 year old son as he starts secondary school. He's aware it will cause him all sorts of problems in school and his teacher will likely hate it, but we'll give it a go. Looking at the GCSE and A-Level calculator requirements in the UK it looks like it would be ok for the exams as long as it is cleared beforehand.

[AnnoyedOne]

(10-19-2024 12:40 PM)dm319 Wrote:  My HP-12c platinum is really not a nice a keyboard ...

My 2022 "Made in Philippines" HP-12C+ is nice. Before I purchased a HP-15C CE I'd read about people having issues with the keyboard. Perhaps I "got lucky" but mine seems fine--even before the 120mS debounce firmware update.

As for the DM15L I have no experience. From what I've read it has a different "feel". The 2-line display is of no interest to me. Since the CE was a limited production run and stock is now low I'd likely go with the DM15L too.

A1

[bxparks]

(10-19-2024 12:40 PM)dm319 Wrote:  I'm planning on getting a DM-15L for my 10 year old son as he starts secondary school. He's aware it will cause him all sorts of problems in school and his teacher will likely hate it, but we'll give it a go. Looking at the GCSE and A-Level calculator requirements in the UK it looks like it would be ok for the exams as long as it is cleared beforehand.

As much as I love RPN calculators, that seems like child-abuse to me... :-) I think I would have gone with a Casio fx-9750GIII. I see them on FB Marketplace over here for as low as US$10. For that price, I would get two, load one of them with KhiCAS, and use the other one for exams. I don't know anything about the GCSE, but this page (https://education.casio.co.uk/curriculum/gcse-maths/) suggests that the CG50 is allowed, so the 9750GIII should be as well.

[dm319]

(10-19-2024 04:41 PM)bxparks Wrote:  As much as I love RPN calculators, that seems like child-abuse to me... :-)

You might not be wrong... But he does have a different way of thinking about things and I suspect he's my only kid who would give RPN a try. I will report back. I explained to my wife that all is not lost if he doesn't get on with it as he can pass it on to me, but now I think she might be on to me.

(10-19-2024 04:41 PM)bxparks Wrote:  For that price, I would get two, load one of them with KhiCAS, and use the other one for exams. I don't know anything about the GCSE, but this page (https://education.casio.co.uk/curriculum/gcse-maths/) suggests that the CG50 is allowed, so the 9750GIII should be as well.

Would you let your kid use CAS? There I was thinking that would be the worst thing for helping your kid to learn but I'm curious if you think differently. CG50 also has an exams mode - but I suspect as long as it is cleared for the exam that isn't necessary.

[naddy]

(10-19-2024 03:23 PM)AnnoyedOne Wrote:  My 2022 "Made in Philippines" HP-12C+ is nice. Before I purchased a HP-15C CE I'd read about people having issues with the keyboard. Perhaps I "got lucky" but mine seems fine--even before the 120mS debounce firmware update.

I'm extremely skeptical that there are differences between units. I suspect it's purely down to individual variation how people press keys. When I got my 15C CE, I worked through all the examples in the Owner's Manual for the first time in decades and those in the Advanced Functions Handbook for the first time ever, and I had barely any problem with key bounce. Probably because I pressed the keys very deliberately. Now that I'm using the CE casually, I run into double key presses too often. (Firmware 2023-01-05.) But as soon as I start paying attention to it, the problem goes away again.

Sadly I couldn't make the time to visit IFA and get some hands-on feel at the SwissMicros booth for the handling of their calculators.