Hornby TTS Sound Class 31

[Ian Hargrave]

Its not really "perceived wisdom", Hornby do state that while a TTS decoder will allow the loco to operate under analogue control, sound will not be available.  Its also interesting that Hornby recently said "look out this Autumn for a further development to our TTS technology...".  I've no idea what they mean by that, but perhaps a feature they might add would be to allow TTS decoders to produce basic engine sounds  under analogue?

 

Wait and see, I suppose! 

 

Yes..I get that.But I do also get some seemingly contradictory views on the current system..at least on this forum...which is the reason for my post.I too have wondered about a further development of the basic TTS kit into analogue control.

[paftrain]

Can I just add, whilst admitting it is teaching granny to suck eggs to many on here it may be of use to some others...

 

Running DCC “decoder equipped” locomotives on a DC layout.

 

Generally..

Most DCC decoders have the ability to run on a DC analogue system, provided the function is turned “on” within the decoder’s set up (see CV29 bit2 in decoder manual.) By default DC operation is usually enabled. Please check the decoder manual for more information. It must be born in mind that running a DCC fitted loco on a DC layout is a compromise.

 

How it works..

As the analogue throttle is increased the DC voltage on the track increases. The locomotives on-board DCC decoder will start up once minimum threshold of voltage is reached, obviously this will lead to a “start-up lag.” Once the decoder has started its first task is to process the track "signal." The processor has to detect whether a true DCC signal is present or whether it has to translate the DC track voltage to a proportional motor control voltage.

 

Unpredictable performance..

The above process is not an ideal solution but, does allow some form of control of a DCC fitted loco on an analogue track. However, there is a likelihood of the locomotive running unpredictably, or with poor control. This is mainly because DC controller’s employ different methods of DC control.. e.g. regulated DC, half-wave rectification, full-wave rectification or quite likely these days “Pulse Width Modulation,” all these different methods of DC control present different voltage wave forms to the decoder. The decoder start up and continuous running etc will be affected in different ways, leading to a certain amount of deviation in DC performance which may be unpredictable.

 

The important bit apart from the various DC control 'waveforms' is when running a decoder equipped loco on DC nothing much happens until you tweak in an amount of track voltage to get the decoders attention, then it takes a while for things to kick in and follow the rules.

 

Rob

 

hi Rob,

That's the most sensible explanation I've seen - well done!

I have a question for you, though - would a loco DCC loco running 'unpredictably' on DC include running in the opposite direction? I have  'Duke of G' with TTS that runs in the right direction on DCC but the opposite direction to everything else on DC! My guess is that it was a Friday afternoon in China and the motor was wired the wrong way round. Will I have to remove the body and swap the wires round on the motor then add 1 to CV29 so I don't upset the DCC direction? I bought it new, so it hasn't been tampered with. Any help will be appreciated.

Regards,

Paul.

[JSpencer]

hi Rob,

That's the most sensible explanation I've seen - well done!

I have a question for you, though - would a loco DCC loco running 'unpredictably' on DC include running in the opposite direction? I have  'Duke of G' with TTS that runs in the right direction on DCC but the opposite direction to everything else on DC! My guess is that it was a Friday afternoon in China and the motor was wired the wrong way round. Will I have to remove the body and swap the wires round on the motor then add 1 to CV29 so I don't upset the DCC direction? I bought it new, so it hasn't been tampered with. Any help will be appreciated.

Regards,

Paul.

It is an 8 pin chip on a wire harness, you could try plugging the chip in the other way into the 8 pin plate.

[Legend]

Its not really "perceived wisdom", Hornby do state that while a TTS decoder will allow the loco to operate under analogue control, sound will not be available.  Its also interesting that Hornby recently said "look out this Autumn for a further development to our TTS technology...".  I've no idea what they mean by that, but perhaps a feature they might add would be to allow TTS decoders to produce basic engine sounds  under analogue?

 

Wait and see, I suppose! 

Not sure they would do that it would possibly torpedo their sales of DCC controllers if you could get sound on analogue .I appreciate you can have this now with certain Decoders, but it's not mainstream. I just think they'll offer most of their range with a TTS option, but to operate on DCC.

[RAF96]

I have a question for you, though - would a loco DCC loco running 'unpredictably' on DC include running in the opposite direction? I have 'Duke of G' with TTS that runs in the right direction on DCC but the opposite direction to everything else on DC! My guess is that it was a Friday afternoon in China and the motor was wired the wrong way round. Will I have to remove the body and swap the wires round on the motor then add 1 to CV29 so I don't upset the DCC direction? I bought it new, so it hasn't been tampered with. Any help will be appreciated.

Regards,

Paul.

I don't think it would cause a loco to run in the wrong direction else this would happen at random, so more likely it is as you say a factory mis-wire. Having all the wires black can't help.

 

There is a standard for testing that a loco and tender have been wired to pattern such that forward throttle makes the loco move to the left when the rails are also wired to correctly polarity, but the hard copy I have is in my files 2000 miles away for the next few weeks, but essentially with a blanking plug fitted to the socket you are looking to see if the basic loco wiring is routed from left wheels through the socket to one motor brush (top or left from memory) and right wheels are routed via the socket to the other motor brush.

 

This is repeated at the tender to check the link wires attach the the loco socket correctly. In the event the socket is in the tender then the same principle applies.

 

The test rails again from memory are right positive and left negative when viewed facing right to left, i.e. loop going anti-clockwise. May be wrong, but a Google on NMRA site should confirm it.

 

Once you have assured that each loco and the test track (analogue) are wired correctly then you can progress to amending CV29 if required. 2mm.org has a handy CV calculator for both CV29 and long decoder addresses (CV17/18).

 

Even without an analogue test track you can still do a comparison of those two opposing locos to check the left and right wheel feeds are connected via the socket to the same motor brushes.

 

Just be aware you must never apply a voltage to the motor brushes direct when there is a decoder installed or you will likely kill the decoder.

 

Edit: TTS in the autumn. Are Hornby not just talking about the release of their retro kits as available on pre-order from their site. The only other thing I can think of that could be useful is factory setting the correct motor algorithm as standard for each model variation that uses the same basic recording but a different motor, e.g. A1, A3, maybe others.

 

Rob

Edited August 8, 2017 by RAFHAAA96

[Hroth]

CV 29 is reasonably straightforward if you're just setting the direction of travel.  As the direction of travel is the first bit (bit 0), it adds 0 or 1 to the total, in other words if its on (set to 1) the value of CV29 will be odd, if off (set to 0) the value of cv29 will be even.

 

So, for a very basic setup:

 

If CV 29 is set to 6 (28/128 speed steps, DC running enabled) then Direction is Normal.

If CV 29 is set to 7 (28/128 speed steps, DC running enabled) then Direction is Reversed.

 

If long addressing is also enabled CV 29 will be either 38 for Normal direction, or 39 for Reversed.

 

 

Basically, if CV 29 is even, then the direction is Normal, if odd, the its Reversed.

 

Binary IS easy, you know..... 

 

Talking about long addresses, I've not played with them as I've never needed to, so I don't know how CV 17/18 work, but my current numbering scheme is getting frazzled, so I'll have to look at how it works in the near future.....

 

edit for clarification.....

Edited August 8, 2017 by Hroth

[JSpencer]

I don't think it would cause a loco to run in the wrong direction else this would happen at random, so more likely it is as you say a factory mis-wire. Having all the wires black can't help.

There is a standard for testing that a loco and tender have been wired to pattern such that forward throttle makes the loco move to the left when the rails are also wired to correctly polarity, but the hard copy I have is in my files 2000 miles away for the next few weeks, but essentially with a blanking plug fitted to the socket you are looking to see if the basic loco wiring is routed from left wheels through the socket to one motor brush (top or left from memory) and right wheels are routed via the socket to the other motor brush.

This is repeated at the tender to check the link wires attach the the loco socket correctly. In the event the socket is in the tender then the same principle applies.

The test rails again from memory are right positive and left negative when viewed facing right to left, i.e. loop going anti-clockwise. May be wrong, but a Google on NMRA site should confirm it.

Once you have assured that each loco and the test track (analogue) are wired correctly then you can progress to amending CV29 if required. 2mm.org has a handy CV calculator for both CV29 and long decoder addresses (CV17/18).

Even without an analogue test track you can still do a comparison of those two opposing locos to check the left and right wheel feeds are connected via the socket to the same motor brushes.

Just be aware you must never apply a voltage to the motor brushes direct when there is a decoder installed or you will likely kill the decoder.

Edit: TTS in the autumn. Are Hornby not just talking about the release of their retro kits as available on pre-order from their site. The only other thing I can think of that could be useful is factory setting the correct motor algorithm as standard for each model variation that uses the same basic recording but a different motor, e.g. A1, A3, maybe others.

Rob

IMHO, before testing the wiring, i recommend unplugging the decoder entirely and replacing it with a blanking plate.

[RAF96]

CV 29 is reasonably straightforward if you're just setting the direction of travel.  As the direction of travel is the first bit (bit 0), it adds 0 or 1 to the total, in other words if its on (set to 1) the value of CV29 will be odd, if off (set to 0) the value of cv29 will be even.

 

So, for a very basic setup:

 

If CV 29 is set to 6 (28/128 speed steps, DC running enabled) then Direction is Normal.

If CV 29 is set to 7 (28/128 speed steps, DC running enabled) then Direction is Reversed.

 

If long addressing is also enabled CV 29 will be either 38 for Normal direction, or 39 for Reversed.

 

 

Basically, if CV 29 is even, then the direction is Normal, if odd, the its Reversed.

 

Binary IS easy, you know..... 

 

Talking about long addresses, I've not played with them as I've never needed to, so I don't know how CV 17/18 work, but my current numbering scheme is getting frazzled, so I'll have to look at how it works in the near future.....

 

edit for clarification.....

For the long address numbers to enter in CVs 17 and 18 go to 2mm.org where there is a handy calculator . Enter your desired long address and it tells you what to put in those CVs. It also works the other way round.

 

They also have a CV29 calculator where by way of tick boxes for the bit features you get the right value of CV29.

Rob

[Hroth]

For the long address numbers to enter in CVs 17 and 18 go to 2mm.org where there is a handy calculator . Enter your desired long address and it tells you what to put in those CVs. It also works the other way round.

 

They also have a CV29 calculator where by way of tick boxes for the bit features you get the right value of CV29.

Rob

I've had a play with the CV17/18 calculators, I might have fun and write a standalone one of my own!

 

Hmmmm....  Something like

1. Get decimal number
2. Range check
3. Convert to binary string
4. Slice string into two (6 bits for CV17, 8 for CV18)
5. Add 11 to the most significant end of CV17
6. Convert binary strings back to decimal
7. Display results

 

Or you could do the same thing with a pocket calculator with a decimal-binary-decimal button, a piece of paper and a pen.

 

As for CV29, why?  Ok, I couldn't quote the bit positions off the top of my head, but its easy enough to find the tables explaining what each one does, then its just a question of adding the numbers up. And once you've done it for your first loco then you'll apply the same value to all the others!

 

 

Ok, its good that others have provided the tools to achieve sensible results without delving into the murky depths of binary.  Otherwise, its a bit like building a Dapol wagon kit!

[meatloaf]

Does anyone else find there 31 a bit on the quiet side? Does anyone know the CV for volume on the TTS decoders?

[Hilux5972]

Does anyone else find there 31 a bit on the quiet side? Does anyone know the CV for volume on the TTS decoders?

Should say in the instruction leaflet that came with the loco.

[Izzy]

Does anyone else find there 31 a bit on the quiet side? Does anyone know the CV for volume on the TTS decoders?

 

There is a full listing of all the various cv's and their settings in the instruction leaflet, which I have to say is quite comprehensive and informative.  You can adjust all the individual spot sounds - separate cv's - or set an overall sound level for all using cv182. There are 8 levels (actually nine, but 0 turns the sound off).

 

The default for all sounds is 4. For home use I actually found I needed to reduce mine down to the lowest of 1. At 8 you could hear it down the road........I actually thought it was real one coming past - well nearly, as we still get the odd diesel tootle along the branch behind us, a noticeable change from the normal swish of the EMU's.

 

Izzy

[John Tomlinson]

Does anyone else find there 31 a bit on the quiet side? Does anyone know the CV for volume on the TTS decoders?

 

Part 7 of the instructions gives the Engine sound as CV161. I found mine a bit quiet as well, and lifted this to 6 which helped a lot. I haven't done the general increase across the functions, but might give it a try to see how it sounds.

 

I seem to remember that earlier in this thread someone installed a different speaker, from You Choos, which they said improved the quality.

 

John.

[Enterprisingwestern]

Somehow, whilst passing my local model shop, Rails of Sheffield, auto pilot kicked in and I seem to have become the proud owner of one of these locos, well, at the price, it was rude not to, and it saved £6,50 posting back home.

I obviously can't have a play until my return, unless I'm allowed to brumm it up and down the aisle of the plane, but on test in the shop it sounded pretty good.

I notice the old detailing sprees from the Lima days are missing, presumably to keep the costs down, at least it gives Brian at Extreme Etchings some business for the headcode discs at least, although I'll be going for the full fat version with all the trimmings.

This is my first Railroad loco, what are they like to convert to the broader gauges?

 

Mike.

[Izzy]

Somehow, whilst passing my local model shop, Rails of Sheffield, auto pilot kicked in and I seem to have become the proud owner of one of these locos, well, at the price, it was rude not to, and it saved £6,50 posting back home.

I obviously can't have a play until my return, unless I'm allowed to brumm it up and down the aisle of the plane, but on test in the shop it sounded pretty good.

I notice the old detailing sprees from the Lima days are missing, presumably to keep the costs down, at least it gives Brian at Extreme Etchings some business for the headcode discs at least, although I'll be going for the full fat version with all the trimmings.

This is my first Railroad loco, what are they like to convert to the broader gauges?

 

Mike.

 

They have correct sized wheels, traction tyres on one side each of the geared power bogie axles, and have 2.5mm axles. I don't know if EM/P4 conversion packs are available from either Ultrascale or Gibson (they may be for the full fat Hornby versions which appear to use different standards), but I have re-machined mine to run on P4. The axles are a force fit in one wheel and splined with a plastic bush in the other. It's currently being detailed. I'll do a thread if there is any interest.

 

Izzy

[Enterprisingwestern]

I for one would be interested in a thread.

 

Mike

[RAF96]

The trick with TTS decoders is to set the overall volume (CV178 for steam and CV182 for diesel) to an acceptable level (mine are set at value 1 for a small room) then adjust the individual sound levels using the other listed CVs to suit your taste.

 

Rob

[Izzy]

I for one would be interested in a thread.

 

Mike

 

Okay, I'll see what I can do, and try and make sure I take a few shots as I do things. I often use them for reference (wiring runs or colours) or to check bits as I go along but forget at other times.

 

The trick with TTS decoders is to set the overall volume (CV178 for steam and CV182 for diesel) to an acceptable level (mine are set at value 1 for a small room) then adjust the individual sound levels using the other listed CVs to suit your taste.

 

Rob

 

 I am glad I am not the only one to find the lowest level quite loud enough for home use. Interesting to discover that the individual levels are relative to the overall one. That is very useful, thanks.

 

Izzy

[Hroth]

Well, it may only be a Railroad TTS loco, but Hornby have sold out, though some retailers still have stock. 

 

Amazing!

[Pint of Adnams]

Well, it may only be a Railroad TTS loco, but Hornby have sold out, though some retailers still have stock. 

 

Amazing!

Not really - it's a well-liked and useful prototype seen on many different types of working, in green with no yellow ends so a rarity these day but still a livery much wanted by those with a certain set of memories, using the more accurate Lima body, an up-dated Hornby drive and sound gubbins too, all for the price of 200 fags (not that I smoke these days).

[Enterprisingwestern]

I believe Rails only had a couple left when I liberated mine.

 

Mike.

[fezza]

I bought one to replace a knackered Lima chassis but I can't really recommend. The chassis is very primitive (old gearing that is too tall, traction tyres - is this 1973??) and it is difficult to eliminate stuttering at slow speeds. It is cheap for a reason. I know it is aimed mainly at youngsters but poor quality stuff like this will only put them off.

 

And if you actually want it to represent an early 60s loco?

Apart from the wrong body, wrong bogies, wrong engine sound and poor performance it is great...

[Enterprisingwestern]

I bought one to replace a knackered Lima chassis but I can't really recommend. The chassis is very primitive (old gearing that is too tall, traction tyres - is this 1973??) and it is difficult to eliminate stuttering at slow speeds. It is cheap for a reason. I know it is aimed mainly at youngsters but poor quality stuff like this will only put them off.

 

And if you actually want it to represent an early 60s loco?

Apart from the wrong body, wrong bogies, wrong engine sound and poor performance it is great...

 

Ah, but, some of us are modellers.

 

Mike.

[meatloaf]

I bought one to replace a knackered Lima chassis but I can't really recommend. The chassis is very primitive (old gearing that is too tall, traction tyres - is this 1973??) and it is difficult to eliminate stuttering at slow speeds. It is cheap for a reason. I know it is aimed mainly at youngsters but poor quality stuff like this will only put them off.

 

And if you actually want it to represent an early 60s loco?

Apart from the wrong body, wrong bogies, wrong engine sound and poor performance it is great...

 

Mine runs ok at slow speeds now ive changed to electrofrog points. On the insulfrogs it stuttered. 

 

For the price its not too bad

[John M Upton]

I tended to find way back when I used to detail and repaint old Lima diesels of which the 31 was probably the best that they often benefited from extra weight and where possible extra pickups too.

 

I don't yet know what the pick up arrangement is on the Limby version but I am sure some tweaking would still be possible.

Edited August 15, 2017 by John M Upton