Hornby HM7000 TXS Decoder Sizing and Comparisons - Will they fit as replacements in older locos?

[@paredding]

Thanks for doing the quick response general overview, I used the Hornby dimensions from their Tech Data tab and measure the space inside my Dapol Class 59. I have ordered 3x TXS 21-Pin as The Class 66 sound will be close enough for me

[@EuviRail]

Thanks for that. You'll have no problems with the 21-pin versions and I would hope that Hornby will introduce Class 59 support in the future given it's a model they've had in their range over the years.

[@Curlypawz]

As Storm Bowman notes, the problem with the Next18 chip is that doesn't meet the NMRA standard and therefore it is unlikely to fit in anything other than a recent Hornby model. I believe that Hornby have stated that this is a temporary issue caused by component shortages and they do plan to reduce the size of this chip in time. It would certainly make sense for them to meet the NMRA standard if they can do so - but the Bluetooth antenna takes up quite a bit of space on what is normally a small chip. The other issue for non-Hornby locomotives using 8-pin or 21-pin decoders is the availability of sound profiles. Since you can't load them from any source other than Hornby, your non-Hornby locomotive may not have an appropriate profile. For some this may not matter and they will just choose something broadly similar, but I'd suggest a typical Zimo or ESU customer may be less forgiving if they have previously sought out an accurate sound profile. According to some reviews you also can't change the function slots around to move the braking to a different slot (for instance) - which may cause issues if you want consistency with existing non-Hornby decoders. While better sounding than TTS, I've also seen it stated by Hornby Magazine that the TXS steam loco chuffs are not synchronised with the wheel revolutions and change the audio in bands rather than a linear increase as speed increases. Again, some may not mind this. Others may consider it a deal breaker. Finally, if you fit a Hornby TXS chip to something with particular lighting setups (for instance) then you may lose some of the fancy lighting options that you have in a Zimo or ESU profile which was tailored for that particular model and its function outputs. I'm not sure how easy that would be to resolve. The Hornby TXS decoders undoubtedly have some neat touches, but I'm not sure that they are likely to cause too much panic for Zimo and ESU just yet. That said, if you have been running DC with a big stock of locomotives and want to switch to DCC sound then you'd save quite a bit of money with TXS.

[@gregmacdonald927]

Useful tables. Many thanks for this. Be interesting to see how much smaller the non-sound ones turn out to be. I think we all assumed these would be bigger. Some tinkering required!

[@EuviRail]

Thanks Greg. The non sound decoders will still have to fit the bluetooth antenna so I have to believe they will be larger and as you say some tinkering will be required.

[@bpresolve]

Well done thanks for the information. Keep up the good work. Bill from W/Australia

[@EuviRail]

Thanks Bill and I hope all is well down under!

[@oldpedro22]

Thanks for that - a useful fact based approach rather than some of the other reviews (particularly on the NEXT18 decoders) which seemed to me to be set up to deliberately find fault with these new decoders. As other have pointed out, the price point of these new Hornby sound decoders is a major selling point over the other more expensive sound decoders as well as the functionality within the app.

[@EuviRail]

Thanks. There's no debating the value aspect for sure and so far I've found the sound quality to be pretty good. We need to see a lot more profiles though.

[@onnomulder9775]

Great video Euvirail!! Thanks for sharing! Cheers Onno.

[@EuviRail]

Thanks Onno

[@tonyburgess7773]

I've been thinking about the TXS Next18 issue. If one is content to use them only on DCC having loaded sound and set them up, might not one then reduce their length by cutting off the aerial?

[@EuviRail]

A valid question Tony. You need the bluetooth connectivity to set up these decoders, programming new profiles and selecting the mode of operation - even if you only intend to use them under DCC. So even if that extended PCB space only contained the bluetooth aerial for example, cutting it off would render the decoder at best restricted to what you had configured on it prior to that (and you could never reconfigure it again), or at worst unusable. You need the bluetooth to manage these puppies even if using DCC control.

[@modeltrainsandtracks]

Thank you for putting this together, very helpful. In my experience Next18 decoders and model manufacturers don't sit well together. I bought a Dapol DMU in N scale and went to fit a Next18 decoder for sound and found the space for the decoder was 5mm shorter than the decoder standard. Clearly that shouldn't be an issue for most OO/HO prototypes though. Additionally I've found that the sockets for Next18 can be poor quality and the decoder can sometimes come loose. Generally speaking I would fit a wired decoder in preference to Next18.

[@EuviRail]

Thanks Martin and thanks for sharing your experience. As you highlight, it works both ways - decoder vendors not meeting the spec and loco manufacturers not provisioning enough space. A wired decoder provides the greatest flexibility for sure.

[@1BCamden]

Great episode, thanks much appreciated. Importantly however, the price has not been included in the comparison, and understandably, as it is a fit, plug and play discussion. Hornby forfeited technology, size, to meet a specific price point. Simon would remind us all that this is a Hornby for Hornby product. The price and accessibility is an industry wake up call

[@EuviRail]

Thanks for that. This video was focused on the size aspect only. In any full relative assessment, these decoders will win out on the value front for sure. I was a TTS fan despite their limitations but the TXS decoders really do move things on quite a bit. This was much needed to shake things up a bit.

[@AndrewJohnson-ur3lw]

According to the specs. The maximum size of a decoder is about 15mm x 10mm. The sound version is called Next18S and has a maximum size of 25mm x 10mm.

[@johnoneill5661]

Hopefully this new system from Hornby will push the other manufacturers to release similar systems and maybe even lower their prices a bit yes ESU I'm looking at you 😁

[@EuviRail]

100% John. I never want to have to spend £100-£120 on a decoder again.

[@theeventhorizon-valebridge9512]

Thank you Eugene, that's a very useful set of comparisons you've provided us with. Top work as usual. Any feedback as to whether they blow easily? Sam of Sam's Trains YT channel reported that one of his HM7000 decoders blew after just 24hrs!

[@Haymarket47]

I believe it was due to the power unit used by “sams trains”. Advice is to use the power brick supplied by Hornby as it meets the demands of the decoders or of course your normal Dcc supply if you have one.

[@EuviRail]

Thanks. Yes, there is an incompatibility with the Gaugemaster controller Sam uses. It comes down to the Pulse Width Modulation (PWM) used by that and other analog controllers. I don't know the specifics, but I'm sure Hornby do at this stage. Simple DC (non PWM) controllers don't appear to have this problem - I'm recording a running session with one of these right now which I'll be posting soon.

[@PeachyTT120]

Good balanced review as expected, although a nod to the fact Hornby really have got the price right down on this might help bring some perspective with regards to the 18pin

[@EuviRail]

Thanks. I was focused on the size aspect. I'm not yet ready to do a full relative scoring but the TXS decoders will definitely win out on the value front.

[@FormallyknownasE100]

I think the main thing with the Next18 is the standard actually defines the decoder sizing and Hornby have gone against this. It’s also that in general the Next18 chips go into the smaller locos. Therefore they are sized to meet the standard. With 8 pin it’s arbitrary and therefore whilst Hornby may be larger than some it’s not unreasonable and any locos that won’t fit the Hornby 8 pin also won’t fit others. The 21 pin it’s designed to the standard so there’s no issue and only locos with a non spec 21 pin interface would have issues. I would though highlight that the speaker and stay alive connections would not fall under these standards though and there many locos may struggle if these are fitted as well.

[@dinmorejunctionmodelrailway]

I have a question you might be able to answer. I use android, and to my knowledge, the app hasn't been released yet. My question is, can an iPhone user download the sound to a TXS decoder for me to use on my android tablet through a Z21 app?

[@EuviRail]

Hi, yes, they can. Get them to download the sound and the function profiles and then set the control to DCC. You can then take the decoder and use it as a DCC sound decoder.

[@dinmorejunctionmodelrailway]

@EuviRail Excellent news. Thanks. Can the same sound decoder be used and operated with a Z21 without sound until the android app is released?

[@stormbowman7148]

The Next18 decoder NEM standard specifies the size of the PCB. Hornby's TXS decoders do not adhere to the standard. Which is why they cannot be expected to fit in any locomotive that follows the standard. Sadly. Rule of thumb: Expect the 21 pin decoder to fit. It follows the size specified by the standard. Expect the Next18 decoder NOT to fit. It is too large for the majority of locomotives as they follow the Next18 standard and do not expect decoders to be larger than that.

[@EuviRail]

Thanks Storm, 100%. I think Hornby should be a bit more upfront on the incompatibility. If I purchase a NEXT18 decoder I expect it to be compliant. Saying Hornby decoders are for Hornby locos isn't really an excuse though I do appreciate the bluetooth antenna challenge they faced.

[@class66]

Still waiting for Android app 😢

[@EuviRail]

Yep, it's running late at this stage. Android has 70%+ of the market albeit it's a more diverse base than the iOS one.

[@alness1289]

I hope Simon saw this and does something , 2 out of three is not bad but , poor considering NEXT 18 has been on the go for ages , He should get his head out of the sand .

[@EuviRail]

At the very least, Hornby should provide a warning to would be purchasers that the dimensions deviate from the standard. Maybe call it "Next18 compatible" or the like.

[@tonyslight826]

Hi do you know if the 8 pin will go into a vi- trains class 37 or 47

[@EuviRail]

Hi Tony, I have previously owned both of these models and had fitted TTS decoders in them. Based on that, the new 8-pin TXS decoders will fit them just fine.

[@tonyslight826]

@@EuviRail thank you.