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.

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 😁

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

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.

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.

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

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!

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

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

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.

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.

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

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!

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.

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 .

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?

Still waiting for Android app 😢

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