Problems with new Econami Steam sound decoder

[jdcolombo]

Hi everyone.

Yesterday, my sample of the new Soundtraxx Economi ECO-100 steam sound decoder arrived, and I promptly installed it in one of my LifeLike Berkshires.

Unfortunately, I cannot recommend this decoder for N-scale steam installations, because you cannot adjust the electronic chuff sync to even come close to the driver rotation.  Even at its fastest setting (CV 114 set to 127), the chuff is way too slow for N-scale - it is as though the chuff timing in the ECO-100 was set up for HO-scale drivers, which are of course much bigger and take much longer to rotate.

This is really too bad, because the sounds themselves are excellent.  The heavy steam chuff has just the right amount of "bark" and really does a good job reproducing what I hear on recordings of NKP 765.  It has a lot of whistle and bell selections, all of which sound superb.   But unless you are OK with one (or maybe 1.25) chuffs per driver rotation on your steam locos, you should stay away from this decoder for now.  I'm going to send a message to Soundtraxx, and perhaps they will look into this and fix it in the future.

John C.

[peteski]

... you cannot adjust the electronic chuff sync to even come close to the driver rotation.  Even at its fastest setting (CV 114 set to 127), the chuff is way too slow for N-scale - it is as though the chuff timing in the ECO-100 was set up for HO-scale drivers, which are of course much bigger and take much longer to rotate.

I'm not sure about that reasoning.  The decoder controls the average voltage to the motor (using PWM like other DCC decoders). It will range from 0 to the track voltage minus coupe of volts.  That controls the motor speed.  The motor drives the locos wheels through a series of gears.  The combination of the motor rpms, and the gear ratio determines how the wheel rotation can be synchronized to the chuff rate.  That to me is scale-independent.

There are many different combinations of motors and gear train in both N and H0 locos.  I don't think that I could make a blank statement that the rotation of the wheels in N scale locos is generally faster than H0 at some decoder speed step.

If some N scale loco has a gear ratio of 1:43 (one wheel revolution per 43 revolutions of the motor armature) and some H0 model has a gear ratio of 1:36 then rotation rotation of the wheels in the H0 scale model will be faster at the same motor rpms. But the other variable is the motor rpms for each given speed step (or voltage) supplied by the decoder.  That is why I wouldn't make this type of a blanket statement.

[jdcolombo]

Yep, you are correct - I shouldn't have made such a blanket speculation.  But surely they tested the decoder with SOMETHING before releasing it, and the most likely test bed would have been an HO scale loco. 

Top Hobby Trains released a YouTube video with one of the Econami deocders in a Kato FEF, and you can clearly see the problem: about 1.5 chuffs per driver revolution at slower speeds (the sync at higher speeds isn't quite so terrible).  They also posted a message on Trainboard saying chuff sync with this decoder in N-scale was "challenging."   I'd say that was an understatement - "impossible" is more like it. 

Sent message to Soundtraxx technical support - will report if I get any response.

John C.

[jdcolombo]

By the way, I should also note that the motor control circuits in the Econami appear much improved from the Tsunami.  I can get my LL Berk to crawl along smoothly at under 1 smph with some adjustment to CV211 (the low speed BEMF amplifier).   It pretty much equals the performance of the ESU LokSound, at least on this locomotive.

And that's another reason the chuff sync problem is so annoying - this has the makings of a great decoder but for that one problem.

John C.

[Cajonpassfan]

Thanks John, but that sure is disappointing, especially if they got the motor control issue fixed....are you sure there isn't some CV combination somewhere to make it chuff faster relative to wheel rotation? I'm sure you tried, hopefully the Soundtraxx folks have a good answer or a fix. Otherwise it's useless.
Keep us posted pls, meanwhile I'm putting my order on hold.
Regards, Otto K.

[peteski]

I'm also really surprised that the chuff rate cannot be adjusted correctly (for any model in any scale).

Reading the manual http://www.soundtraxx.com/manuals/Econami-Steam-Users-Guide.pdf it states that the chuff rate is automatically controlled (I assume by being in sync with the BEMF of the motor drive) and the CV114 is merely a fine tuning adjustment. Almost sounds like a bug in the decoder's firmware.

As an alternative you could try setting the decoder to emulate an articulated loco (with no wheel slip). That will double the chuff rate.

EDIT: this paragraph from the manual confirms that this decider uses BEMF for chuff synchronization.
Auto-Exhaust
2-cylinder exhaust for a light steam locomotive has been enabled by default. The chuff rate is synchronized with motor load compensation based on back-EMF measurements. In other words, the exhaust chuff rate will respond to the speed of the motor. For instance, the chuff rate will become more rapid when the motor is spinning faster, and slower when the motor is impeded. To adjust the Auto-Exhaust chuff rate, refer to “Configuring Sound Effects.”

[jdcolombo]

Like Peteski, I think this is a software "bug." 

It's almost as if the decoder is expecting to see a much higher number of motor revolutions per driver revolution than is the actual case with my Berk.  And there isn't enough adjustment room in CV114 to bring it in sync (it is interesting that CV114 is limited in adjustment to 0-127, as opposed to 0-255).   But it's like the decoder expects to see, say, 100 motor turns per quarter driver revolution (one chuff), but the Berk only needs 25 turns.  So you only get one chuff per complete driver revolution instead of 4.   In theory, this "default" number, whatever it is, should be adjustable across a wide range - that's what CV114 should allow you to do.   But there's just not enough adjustment range - at least not for my LL Berk.  This presumably is a software issue - the software sets both what the "default" number of motor turns to one chuff is, and how wide the adjustment range is.   It looks to me like the default is too high and/or the adjustment range is too narrow.

I read through both the operator's manual and the Tech Ref manual on Soundtraxx's web site, but I couldn't find any adjustment other than CV114 for the chuff rate.  I tried other things, like adjusting the values in CV's 2, 5 and 6 - this got me an excellent speed curve for the engine, but no joy on chuff sync.   I also tried adjusting the reference voltage for the BEMF circuit (CV215?), thinking that might help, and it did have some effect, but not enough.  There's just no way I can find to get the chuffs fast enough to match the driver rotation at slow speed (e.g., speed steps 1-4 out of 28).   I can tell you that I don't have this problem with the regular Tsunami - I can always get the chuff rate to match the driver rotation at slow speed.   The problem with the Tsunami is that because it doesn't use the BEMF circuit to vary the chuff rate, the chuffs never stay in sync at speeds other than what you set the initial timing at.  So it might be perfect at speed step 2, and then out of sync by speed step 4 (out of 28).

The other thing that is interesting is that the ESU LokSound uses two CV's to adjust chuff sync.   CV57 is the base timing, which you set at speed step 1.  Then you open the throttle to speed step 4 (out of 28) and use CV58 to fine tune the chuff sync at the higher speed.   According to the ESU manual, CV58 gives the decoder information about the overall gearing of the engine, so that it can properly calculate the chuff rate at each speed setting.  QSI also uses two CV adjustments (56.11 and 56.12) to accomplish chuff sync in its Revlolution decoders (I assume the new Titan is similar).  The Econami only has one adjustment.  I'm not sure why you need two adjustments - if the driver rotation rate is linear (e.g., say one driver rotation per 100 motor revolutions), then it seems you would only need to set the base timing, and everything would work from there.   All I know is that the ESU and QSI systems flat out work - (QSI provided the sound for the Walthers/LL 2-8-8-2), and the Econami's doesn't.  At least, not for my Berkshire.

I hope I can get some feedback either from Soundtraxx or some dealers I contacted to see if they were having similar issues.   Right now, the decoder is simply too new to get field test feedback.   It's possible I'm doing something wrong, but if so, I sure can't figure out what it might be.

John C.

[nscaler711]

Ok, so what about the Diesel version? I'd like to know more on those if possible.

[Cajonpassfan]

John, out of curiosity, did you try to go beyond 127 to see what might happen?

[peteski]

From the way I interpret the manual CV114 is more like a trim or finie-tuning register rather than a fully blown way to adjust the chuff rate.

It is almost like the decoder's designers made this decoder for some specific locomotive (with its particular motor and gear ratio).  Like they didn't realize that different manufacturers (or even different models from the same manufacturer) and different scales all have many different motors and gear ratios.   But why would a seasoned sound decoder manufacturer assume such thing?  Weird.

BTW, what is the adjustment range of CV 114?  You say at the lowest settign you get about 1.5 chufs/rev. What is the rate @CV114=127?

Did you try putting it into the articulated loco mode?  Just to see how it sounds/

[victor miranda]

I understand part of how a BEMF sensing works includes
counting the commutator plates as they revolve.

if one is attempting to match chuff rates to drivers
somewhere in the decoder programming has to be a number
to match the wheel rpm to the commutator plates per minute.

it may well be the designers did not understand how wide the range is.

[jdcolombo]

From the way I interpret the manual CV114 is more like a trim or finie-tuning register rather than a fully blown way to adjust the chuff rate.

It is almost like the decoder's designers made this decoder for some specific locomotive (with its particular motor and gear ratio).  Like they didn't realize that different manufacturers (or even different models from the same manufacturer) and different scales all have many different motors and gear ratios.   But why would a seasoned sound decoder manufacturer assume such thing?  Weird.

BTW, what is the adjustment range of CV 114?  You say at the lowest settign you get about 1.5 chufs/rev. What is the rate @CV114=127?

Did you try putting it into the articulated loco mode?  Just to see how it sounds/

The 1.5 WAS at 127.   When I first tried the decoder out, it was about 10 seconds (literally) before I heard a chuff.  For a moment, I thought that perhaps the chuff volume had been turned all the way down.  But then I heard one.  And then ten seconds later, a second one.

So I entered 127 in CV114, and that got me to about 1.5 chuffs per driver revolution at speed step one.  At higher speeds (say, 30 smph), the sync got closer - maybe three chuffs per revolution, rather than 1.    But it was never even close at lower speeds, even with CV114 turned all the way up.

I didn't try articulated mode; never thought about it.  But one problem is that at least with the Tsunami, the articulated chuffs are not even - it is two in rapid succession, followed by a pause, then two more, etc.

It's really weird.  As you said, I can't believe the folks at Soundtraxx actually MEANT to do this; it's got to be some sort of crazy oversight, like the spacecraft that was lost because someone forgot to translate imperial units into metric.   And I guess it's possible that I'm just not adjusting something correctly, but if that's the case, it sure isn't explained in the available documentation.

John C.

[peteski]

I understand part of how a BEMF sensing works includes
counting the commutator plates as they revolve.

if one is attempting to match chuff rates to drivers
somewhere in the decoder programming has to be a number
to match the wheel rpm to the commutator plates per minute.

it may well be the designers did not understand how wide the range is.

Other steam sound decoders which use BEMF for chuff sync (like a virtual chiff-cam) do have at least 2 CV registers dedicated to calibrating the chuff rate. Those (like the QSI decoders) can pretty much achieve perfect sync.  On those decoders (as one would expect) slowing down the loco by pressing down on it by hand also slows down the chuffs (they stay in sync with the driver/motor rotation). If you hold the running loco hard enough to stall it, the chuffs stop to.

[Burlington Bob]

Maybe there's more to the name than anybody thought.

[carlso]

Bob, that is an interesting thought and in today's world could be the case.

My thought is this, and I am not going to discuss how the decoder works or should work. I do not know the individual engineers who designed this Eco 100 version, maybe some of you do. That person may be a young person who has only been exposed to steam down below their office in Durango and only a short amount of time learning about steam "chuffs", more in tune with diesels running in 8 slot on the mainline. So, it is possible that there was an oversight regarding the N scale size requirements, If so, I am sure Soundtraxx will correct that real quick or post instructions on how to adjust the chuff properly. The next thing that is possibly the culprit is that they finally woke up to the fact that ESU was eating their lunch and eroding the demand for their Tsunami 750, went to the drawing board and hastily put together a new , less expensive decoder.

From what John has posted, BTW John thank you, I would say they have pretty much succeeded with a narrower board, better motor control all of the items that I am sure they have read off of the forums. The price is certainly much more tolerable. So I thank them for stepping up, with a new steam decoder. They will fix this problem for all to enjoy the steam sounds. I wait with abated breath!

Respectfully,
Carl