Bachmann DCC Sound on DC Problems

[TangerineWizards]

I am a complete novice when it comes to DCC and even more so when it comes to DCC Sound, but I thought I’d move with the times and invest in a cut price Bachmann Class 150 sound fitted model to try on my DC layout, having read that they work on DC but without the operators choice of sound. 
 

Now the model has arrived, I’ve tested it and found my Hornby DC controller has to be on full power to make it move at just a snails pace, although the sound is good. 
 

My question is - is this likely because the Hornby controller can’t supply enough power? I have one that says it supplies 16v to the track and another that says it supplies 19v. The 19v makes it move slightly but the 16v only initiates the sound. 
 

Or is this likely a problem with the model, as my DC locos move as expected fast and slow on command?

 

I am very tempted to invest in a DCC controller but this is a mystery I’d like to solve initially. 

 

Any help for a DCC newbie would be appreciated. Thank you!

Edited September 7, 2023 by TangerineWizards
Updated title to explain I have a problem

[Dungrange]

48 minutes ago, TangerineWizards said:

My question is - is this likely because the Hornby controller can’t supply enough power? I have one that says it supplies 16v to the track and another that says it supplies 19v. The 19v makes it move slightly but the 16v only initiates the sound. 

 

What is the Hornby controller that you are using?  The DC output should normally be marked as 12V, not 16V or 19V.  16V is normally an uncontrolled output for accessories.  However, it's actually the current output that is more important than the voltage.  This will either be given as, say 0.5A or it will give the power rating in either Watts (W) or Volt-Amps (VA).  A 12V output with 6VA would be 0.5A (ie 12V x 0.5A = 6 VA).  However, apart from the very basic train set controllers, I wouldn't have expected a problem - ie I wouldn't expect it to be drawing more than 0.5A.

 

I would expect that you will have to turn the controller up further than you would with a DC locomotive, as you normally need something like 7 V to 'wake the chip up'.  Once the voltage is high enough to power up the decoder, the sounds should start and after the start-up routine is complete, it should begin to crawl forward, accelerating gradually until it reaches maximum speed.  I note you refer to an APA box in your signature.  Over what distance as you running this unit?

[TangerineWizards]

17 minutes ago, Dungrange said:

 

What is the Hornby controller that you are using?  The DC output should normally be marked as 12V, not 16V or 19V.  16V is normally an uncontrolled output for accessories.  However, it's actually the current output that is more important than the voltage.  This will either be given as, say 0.5A or it will give the power rating in either Watts (W) or Volt-Amps (VA).  A 12V output with 6VA would be 0.5A (ie 12V x 0.5A = 6 VA).  However, apart from the very basic train set controllers, I wouldn't have expected a problem - ie I wouldn't expect it to be drawing more than 0.5A.

 

I would expect that you will have to turn the controller up further than you would with a DC locomotive, as you normally need something like 7 V to 'wake the chip up'.  Once the voltage is high enough to power up the decoder, the sounds should start and after the start-up routine is complete, it should begin to crawl forward, accelerating gradually until it reaches maximum speed.  I note you refer to an APA box in your signature.  Over what distance as you running this unit?

You could have potentially solved it as I’ve only been running in a small space. The APA box is gone but only replaced with a scale scene baseboard. 
 

I’ll set up a circle of track over the weekend and see if the speed increases over a longer distance. 
 

It is the Hornby train set controller I am using. I’ve been modelling for 20 years and only ever upgraded to newer versions of the basic Hornby controller.

 

Thanks very much for your helpful reply.  

[Dungrange]

4 minutes ago, TangerineWizards said:

You could have potentially solved it as I’ve only been running in a small space. The APA box is gone but only replaced with a scale scene baseboard. 

 

Okay - in DCC there are many Configuration Variables (CVs) that are used to control how the unit will respond.  CV3 sets the rate of acceleration.  A value of zero would mean that there should be an instantaneous response to a throttle change (ie it should behave just like driving on DC).  However, if it has a high value then it will take a long time for the vehicle to begin moving and it will take a long time to reach maximum speed.  With a non-sound decoder, you can set the value in CV3 as you please.  However, because you have a sound model, the acceleration rate will have been chosen by whoever created the sound project, so that the rate at which the model accelerates matches the way the prototype from which the sound files were captured accelerates.  This therefore forces you to drive in a similar manner to how you would drive on the real railway (which is not 0-60 in 2.5 seconds).  If you can set up a circle of track and test it on that, I'm hoping that it will work - you'll just find that it might take 20 seconds to be going fast.

[andyman7]

A Hornby train set controller won't have enough oomph to get the best from this model. The way the decoder is configured, on DC quite a lot of current is used to initiate the sound and allow a 'start up' sequence and engine idle before it moves. If you want to use a small set size controller I would highly recommend the Gaugemaster Combi - small and light but much more robustly engineered than any Hornby train set controller - and with enough output to work the sound.

https://www.gaugemasterretail.com/gaugemaster-gmc-combi.html

[pauliebanger]

On 07/09/2023 at 21:59, Dungrange said:

 

Okay - in DCC there are many Configuration Variables (CVs) that are used to control how the unit will respond.  CV3 sets the rate of acceleration.  A value of zero would mean that there should be an instantaneous response to a throttle change (ie it should behave just like driving on DC).  However, if it has a high value then it will take a long time for the vehicle to begin moving and it will take a long time to reach maximum speed.  With a non-sound decoder, you can set the value in CV3 as you please.  However, because you have a sound model, the acceleration rate will have been chosen by whoever created the sound project, so that the rate at which the model accelerates matches the way the prototype from which the sound files were captured accelerates.  This therefore forces you to drive in a similar manner to how you would drive on the real railway (which is not 0-60 in 2.5 seconds).  If you can set up a circle of track and test it on that, I'm hoping that it will work - you'll just find that it might take 20 seconds to be going fast.

A great explanation of inertia control by decoders on DCC and what useful effect that has.

However, I would expect a factory sound fitted model sold as ' will operate on DC' to have CVs 3 and 4 automatically disabled when operating on DC. This is indeed the case with the Bachmann Class 150. (CV14 bit 6).

Paul 

[TangerineWizards]

Thanks very much for everyone’s comments and assistance with this. I understand DCC much better just from these tips. 
 

I’ve tried the model on a loop of track this morning and it never got above a crawl. Assuming the CV needs changing, would I be able to do this on an entry level DCC controller such as the new Bachmann EZ DCC Plus, released this week? Or would I need something more specialised. 
 

That is assuming that an entry level DCC controller wouldn’t resolve the speed issue regardless of the CV setting being high? 
 

I should point out this was bought second hand on eBay so I imagine the previous owner had changed it from factory settings.

[Dungrange]

3 hours ago, TangerineWizards said:

I’ve tried the model on a loop of track this morning and it never got above a crawl. Assuming the CV needs changing,

 

Okay, but @pauliebanger, who is far more knowledgeable on the subject than I am, has stated that the decoder should automatically disable the values in CV3 and CV4 when operating on DC.  Of course, as you've highlighted, the original user may have changed the settings, so we can't guarantee that it is or isn't the decoder settings.  However, we probably need to jump back to the DC controller that you are using.  You've described it as a basic Hornby train set controller.  I've got one of these (it's about 35 years old now) and it's rated at 0.25 Amps.  If your sound fitted unit is trying to draw say 0.5 Amps and your train set controller is only capable of supplying 0.25 Amps, then it will never go at more than crawl simply because it's not getting enough power.  Unfortunately, the Hornby website is next to useless when you go to Technical specs.  It claims that a wall mounted transformer is 00 gauge, but doesn't give any details about voltage, current or power.  Some of Hornby's controllers are more powerful (eg the HM 2000 is apparently 2 Amps), but it may simply be that the unit is trying to draw more power than the controller you are using can provide.  Do you have a multi-meter?

[drt7uk]

Could I 'chip in' here and ask a novice question too...sounds like you're saying that a DCC sound fitted model should in theory work on a non-DCC layout? 

 

I just bought 'Bachmann Branchline 31-090DS Class 32xx 'Earl' 4-4-0 3206 "Earl of Plymouth" in GWR green - DCC sound fitted' because I wanted the model and I couldn't find any more non-DCC models left in the livery I wanted...

 

...I was assuming I'd need to get a DCC blanking plate?

 

Is that not the case? Controller wise I have a Gaugemaster D controller.

 

Thanks v much

Edited September 17, 2023 by drt7uk

[drt7uk]

And if a blanking plate is needed, what would I need to purchase for the Bachmann Branchline 31-090DS Class 32xx? (How many pins is the chip?)

[Kaput]

Most (not all but most) sound decoders will work on DC control to a degree. Hornby TTS and TXS decoders are a notable exception, they cannot do sound on DC.

 

As mentioned elsewhere you will probably find the controller needs turned up quite far to get enough juice to power up the decoder and it can make it more challenging to control than a normal DC model.

 

There may already be a blanking plug supplied with the model but if not, I believe that one is a 21pin decoder and since theres no lights or anything it shouldn't require anything special blanking wise.

[drt7uk]

Thanks @Kaput!

[Ron Ron Ron]

On 17/09/2023 at 16:43, drt7uk said:

Could I 'chip in' here and ask a novice question too...sounds like you're saying that a DCC sound fitted model should in theory work on a non-DCC layout? .....

 

Most DCC decoders (sound or non-sound) will work under DC control, unless DC running has been disabled in the CV settings, in which case, they won't work under DC at all..

(This is usually done to prevent runaways).

If DC running has been disabled, then you will need a DCC system, or computer program with an interface (e.g. a Sprog) to access the CV settings to enable DC running.

 

When it comes to sound decoders, sound operation is limited and not always consistent on DC running.

Various sound effects can't be accessed either.

 

Also, as already mentioned, Hornby's TTS and TXS decoders will not produce any sound under DC control.

 

 

You can buy a DCC system for the price of 1 or 2 new locos.

Don't buy the EZ DCC Plus though. It is very limited in what it can do and you can't change CV's through it.

 

 

 

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Edited September 20, 2023 by Ron Ron Ron