DDC fitted, running better in DC?!!

Post all your DCC only problems, solutions and discoverys here.
matt1471
Posts: 333
Joined: Tue Dec 16, 2008 6:13 pm

DDC fitted, running better in DC?!!

Postby matt1471 » Tue Nov 29, 2011 6:07 pm

In the absence of my DCC controller (normally a Hornby Elite which is currently in for some repair) I wired up my layout to my Gaugemaster Model D controller and ran a couple of DC loco's to make sure everything was good throughout the tracks and sort any little problem areas out.

I then wondered if a DCC fitted train would work on DC and found out that it does.....very well indeed and more so, better than it does in DCC!! The train did not stall, stutter and ran alot more smoother than on DCC.

Now, admittedly I'm using cheapy Hornby decoders, but I've got a couple fitted with Bachmann EZ decoders and also one with a TCS decoder, but either way, I'd say they run better in DC.

So, is this down to poor DCC controller choice (I've got the 4amp PSU) or cheapy decoders??

Thanks
Matt

User avatar
Essex2Visuvesi
Posts: 2357
Joined: Thu Aug 28, 2008 4:51 pm
Location: Finland, Finland, Finland!

Re: DDC fitted, running better in DC?!!

Postby Essex2Visuvesi » Tue Nov 29, 2011 6:20 pm

Most loco decoders are able to run in DC mode unless they have been programmed not to.
Im suprised they run better tho!
Si quam primum vos operor non successio , impono

The only stupid question is the one I didn't ask

Proud member of the OAM
(Order of the Armchair Modeller

User avatar
Flashbang
Posts: 3798
Joined: Thu Oct 18, 2007 1:07 pm
Location: SE United Kingdom
Contact:

Re: DDC fitted, running better in DC?!!

Postby Flashbang » Tue Nov 29, 2011 7:03 pm

Hi
The only reason I can think of is that your dc controller outputs a higher rail voltage than your DCC system does.
[Image << Click the Icon to go to my website
Broken? It was working correctly when I left it.

Bigmet
Posts: 8166
Joined: Tue Aug 14, 2007 2:19 pm

Re: DDC fitted, running better in DC?!!

Postby Bigmet » Tue Nov 29, 2011 7:46 pm

Mostly the decoders would be my take. When a decoder sees a DC signal on the track it leaves the control to the DC system, so what you are seeing is the quality of the gaugemaster unit (and these are good units) with the loco chassis. Those loco chasis have the potential to run equally well at minimum and typically better on DCC control,particularly because of the way the decoder can be set up individually for the chassis it is installed on.

When you get your DCC system back treat yourself to a Lenz or Zimo decoder, and see what DCC control can be like.

matt1471
Posts: 333
Joined: Tue Dec 16, 2008 6:13 pm

Re: DDC fitted, running better in DC?!!

Postby matt1471 » Tue Nov 29, 2011 8:10 pm

Hi Bigmet,

Thanks for the reply. I thought it would boil down to the decoders. Are the Bachmann EZ decoders not that good either then??

I've got a Hornby Class 50 with an ESU decoder which I guess is OK, but from seeing the trains move in DC, appeared a whole lot better. Are things like CV and Start-up values likely to improve movement for each chassis?? What values do I need to be looking at to improve things here??

Thanks
Matt

matt1471
Posts: 333
Joined: Tue Dec 16, 2008 6:13 pm

Re: DDC fitted, running better in DC?!!

Postby matt1471 » Tue Nov 29, 2011 8:30 pm

Looking at the variety and costs of such decoders does put me off, but I understand money buys quality.

How do the Digitrax DN135PS and LokPilot Basic V1 fair up for better running??

http://www.dccsupplies.com/shop/product_info.php?cPath=459_182_201_207&products_id=2864Digitrax

http://www.dccsupplies.com/shop/product_info.php?cPath=459_182_201_207&products_id=2693Lok Pilot

Matt

User avatar
poliss
Posts: 1661
Joined: Mon Jun 20, 2005 5:28 pm

Re: DDC fitted, running better in DC?!!

Postby poliss » Tue Nov 29, 2011 11:31 pm

They might run better on DCC if you turn DC off in CV29. There's not much more you can alter with Hornby decoders. You do have them set to 128 speed steps of course?
There's a guide for fine tuning decoders here. http://www.nmra.org.au/gndu/EasyDCC/Decoders.pdf
One for CT Elektronic decoders here. http://www.2mm.org.uk/articles/CT-decoders.htm

matt1471
Posts: 333
Joined: Tue Dec 16, 2008 6:13 pm

Re: DDC fitted, running better in DC?!!

Postby matt1471 » Wed Nov 30, 2011 2:26 pm

How would turning off CV29 improve things??

What else could it be then that is causing me not to notice such efficiant running in DCC??

Is the Elite a poor controller in terms of accuracy, or could it be the decoders/CV settings?

Bigmet
Posts: 8166
Joined: Tue Aug 14, 2007 2:19 pm

Re: DDC fitted, running better in DC?!!

Postby Bigmet » Wed Nov 30, 2011 4:13 pm

matt1471 wrote:...I've got a Hornby Class 50 with an ESU decoder which I guess is OK, .. Are things like CV and Start-up values likely to improve movement for each chassis?? What values do I need to be looking at to improve things here ...

The adjustability of the decoder to suit the chassis and get the running you want is a key part of DCC. Usually there are just half a dozen CVs that need adjustment for running purposes.
Temporarily set CVs 3 and 4 to minimum, or disable them on the control unit as this makes the set up easier.
CV2 - start. Set it to the lowest value at which the loco motor just moves the loco on speed step 1.
CV5 - top speed. Set it to a value which gives the maximum speed you want from that loco. I use a timed run on a circuit for this, and for the CV6 adjustment.
CV6 - mid speed. Set it to a value which gives the speed you require, on the middle speed step.
(I set CVs 5 and 6 to one of three top and mid speed combination groups, depending on type of loco; that way I can run 'any with any' from a group in multiple, which I find convenient.)
CVs 3 and 4, acceleration and braking inertia. Set these according to taste; you might not like my choices of values 100+, but these generate the genuinely slow and smooth acceleration of real rail vehicles. I set mine up to match rates within the groups already mentioned - unfortunately you cannot just plug in the same values on each decoder and expect to get a perfect match - put in the nominal value, then adjust by comparison to a reference loco.

Sometimes you need CV29 to switch off DC (can help control on some locos, with some systems) or to reverse a loco which is wired wrong way round. The ESU decoder in your 50 should give you some idea of the adjustment capability.

Once in a while a chassis needs very much more adjustment. This is where well specified decoders come into their own. Fairly cheap and nasty drives can be strongarmed into perfoming rather better then many would believe possible in the iron grip of a good decoder...
...Are the Bachmann EZ decoders not that good either then...

The two Bachmann decoders that are definitely decent are their 36-553 and 36-554 (8 and 21 pin respectively) these are badged ESU lokpilots. For budget items they have a first class drive, but limited adjustments, which is what keeps the cost low. Some chassis may need more adjustment than these can provide. Next step up would be a Lenz Standard.

matt1471
Posts: 333
Joined: Tue Dec 16, 2008 6:13 pm

Re: DDC fitted, running better in DC?!!

Postby matt1471 » Fri Dec 02, 2011 2:09 am

From another Forum (modelrailforum) the general concensus there is to remove the capacitors from the loco when fitting a decoder??

Is this something people have done on here?? It seems a bit odd that a DCC 'ready' loco needs to be modified to run at its optimum in DCC?

User avatar
Essex2Visuvesi
Posts: 2357
Joined: Thu Aug 28, 2008 4:51 pm
Location: Finland, Finland, Finland!

Re: DDC fitted, running better in DC?!!

Postby Essex2Visuvesi » Fri Dec 02, 2011 6:15 am

I don't think DCC ready locos have them.
Ive removed the capacitors on all the locos I have chipped
Si quam primum vos operor non successio , impono

The only stupid question is the one I didn't ask

Proud member of the OAM
(Order of the Armchair Modeller

Martin71
Posts: 160
Joined: Mon Apr 16, 2007 8:47 am
Location: Perth WA

Re: DDC fitted, running better in DC?!!

Postby Martin71 » Fri Dec 02, 2011 6:57 am

Hi
Yes the will run better on dcc with a medium to good quality chip added.

Now DCC Ready means the loco is ready to take a decoder nothing more. It doesnt mean the loco will run any better with a decoder added in fact it could be actually worse or not run at all. That a bit extreme but I am trying to help you understand DCC ready.

Manufacturers by law have to add the suppression caps. They need to comply with CE regulations and to cover themselves they add them to all locos even knowing that it may cause problems.

I always remove them on every DCC install I do. If you want a medium to good quality decoder look at the DCC Concepts range, they are excellent and another I tested which for the price was excellent including great features the Trainsave decoder by Hattons.

Hope that helps,

m

1d89
Posts: 23
Joined: Mon Jan 26, 2009 4:04 pm

Re: DDC fitted, running better in DC?!!

Postby 1d89 » Fri Dec 02, 2011 5:20 pm

Have to agree that the Trainsave decoders are a very good cheap option. The Bachmann 3 function decoder is also a good value decoder that with the cv`s set correctly will give excellent performance, not to be confused with the Bachmann 2 function which will not perform as well and make the motor growl.
As already pointed out I would say that you need to start tweeking cv`s. A loco with clean wheels on clean track will never run more prototypically than on DCC with a decent decoder.
An simple example of a Bachmann 3 function decoder cv settings
CV 3 acceleration 10
CV 4 deceleration 6
CV 5 max speed 40 (Range is 0-63)

As for removing capacitors I caint say I have ever noticed any difference. For example I have 6 Heljan class 47`s all fitted with TCS t1`s, all run faultlessly with the capacitor surpressors still on the pcb. I removed the capacitor from one and it had no effect at all. It may have more of an effect on older loco`s, the only older stock I have is a Lima 101 which I fitted with a Lenz standard but I removed the capacitor before I had tested it without.


Return to “DCC Forum”

Who is online

Users browsing this forum: No registered users and 5 guests