ESU Lok Sound 5 in Kato N GS-4: Adjusting Chuff Rate?

[tehachapifan]

While I have lots of diesel sound install and programming experience, steam is new to me with my new GS-4 being my first steam sound install. I have the 58731 drop-in board installed with sound file S0737. Tonight, I was trying to play around with adjusting the chuff rate and thought changing CV's 2, 5 and 6 would do it, but this doesn't seem to be the case. It still has the same chuff speed when the loco is moving at a given (actual) speed, even though the speed step displayed may have been changed after the CV adjustment. Plus, I'm not absolutely sure what the chuff rate is supposed to be based on. My assumption is it's one chuff per piston rod (correct term?) movement outward from the forward cylinders on both sides, correct? If not CV 2, 5 and 6, what is the trick to more closely matching the chuff rate?

[peteski]

Like all simple 2-cylinder locomotives, there are 4-chuffs/driver revolution.  CVs you mentioned have nothing to do with adjusting chuff synchronization.

There is an extensive discussion (with the info you are seeking) about this on the groups.io LokSound group thread started by Dwight.

Not sure if you can view it without joining the group, but since you are ESU decoder user if you are are not a member, I highly recommend joining that group.
https://groups.io/g/Loksound
Link to the discussion
https://groups.io/g/Loksound/topic/did_a_steam_loco_auto_tune/89429529?p=Created%2C%2C%2C20%2C2%2C20%2C0&jump=1 (the meat of the discussion is in several most recent posts.

[RBrodzinsky]

From the manual

13.3. Synchronizing the steam chuff
To synchronize the steam chuff with the wheel revolutions, you may use an external cam as described in chapter 6.11. However, most users prefer not do such massive changes on their valuable locomotives and prefer to use the automatic exhaust mode of the LokSound 5 decoder. Because of the excellent Back-EMF function, the synchronization will be satisfying most users.

To enable this function (and disable any external cam at the same time), CV 57 and CV 58 are used. All you need is a stop-watch and a little time. It pays to spend some time in order to achieve an optimal result. Please make sure that the load control is perfectly adjusted to your loco and set the maximum / minimum speed according to your wishes. After doing so, you should start to synchronize the steam chuff.

In CV 57, the distance between two steam chuffs at the lowest possible speed (at speed step 1) is defined. The unit of CV 57 is a multiple of 32 ms (Milliseconds). In CV 58, you need to give the LokSound some information about the gearing of your engine.

Please proceed as follows:
1.   Put the engine onto the track and drive it with speed step 1 and switch the sound on.
2.   Using the stop-watch, measure the time in seconds it takes the driver to complete one turn at this speed.
3.   Divide the time by 4 (assuming you are using a 2 cylinder or 4-cylinder locomotive)
4.   Enter a rounded value without decimal point in CV 57. We recommend to use POM to be able to observe the result imme¬diately.
5.   Observe the locomotive thoroughly and check if there are now produced too many steam chuffs per revolution. If needed, ad¬just the value of CV 57 gradually by increasing or decreasing the value one by one.
6.   If you are satisfied, increase the speed of your locomotive to speed step 4 (of 28).
7.   Try to observe, if still four steam chuffs per revolution can be heard. If you find that there are too many steam chuffs, incre¬ase the value of CV 58 (defaults to 43). If they are too slow, decrease the value of CV 58. This procedure will calibrate the gear factor of the LokSound decoder.

13.3.1. Minimum distance of steam chuffs
Quite small driving wheel diameters are likely to make the steam chuffs sound very good at small and medium speeds; however during high speed it sounds strangely distorted and ticked off. This has often to do with an excessive terminal speed that isn´t prototy¬pical at all. The minimum distance, which two steam chuffs need to have, can be set with the help of CV 249 to reach a satisfactory sound. A unit of 1 ms allows a quite exact adjustment.

If you are still not satisfied with the sound during high speed, you should increase CV 249 gradually while the sound is switched on, until the sound gets more natural since the steam chuffs are set further apart.

[peteski]

Ah yes, the dreaded manual!    That sounds like a long and daunting procedure.    But I do agree that it is always good to really understand what's going on, and how things work.

Cutting through the chase, here is the GS4 cheat from the LokSound group.

• CV57 = 80     (as set by the Auto Tune CV54=0 )  CV53 = 65
• CV57 = 77          CV53 = 79
• CV57 = 77         CV53 = 80

[Dwight in Toronto]

Tehachapifan … I think you and I are moving in ‘Lok’step with our GS-4 projects, and I have you to thank for starting me down that path.  When I saw you ask about that 58731 decoder a couple weeks ago, and guys like Peteski and Kelley were adding interesting commentary, well, I just had to follow in your footsteps and equip my prized steam loco with sound.

As Pete says, please check out the i/o LokSound group topic … I asked the very same chuff sync question yesterday, and it generated an interesting and informative series of constructive comments. It was most helpful and enlightening. 

In fact, this particular forum has helped me out tremendously on 4 or 5 occasions over the last six months, regarding various LokSound decoder nuances.  There are some very encouraging and helpful folks on that site who are scary-proficient with all things ESU, as well as DecoderPro etc.

[jdcolombo]

It's really not as hard as it sounds.  But I do spend about an hour adjusting a steamer as set forth below.

First step is to get the engine running as well as it can, which usually requires some playing around with CV's 51, 52, 54, 55 and 116-119.  Auto-tune helps, but manual fiddling almost always is required for absolute best performance.

Second, set CV53 to a value that is 10x your track voltage.  My track voltage is 13v, so I set CV53 at 130.  CV53 adjusts "voltage spread" on your thottle.  So after setting CV53, check to make sure that the engine moves at SS1 (it should do so with a setting of "2" in CV2) and that it doesn't hit full speed until you max out the throttle - if you hit full speed at  1/2 or 3/4 throttle, you'll need to adjust CV53.  Once you have CV53 set, LEAVE IT ALONE and DO NOT LET AUTOTUNE RESET IT.

Third, put the engine on the track and go into ops mode programming (programming on the main).  Set CV57 at 70 and CV58 at 25.  Now crack the throttle open to ss1 and observe the chuffs.  Adjust CV57 up/down as necessary to achieve the best possible match of 4 chuffs per driver rotation.  You should be able to get this darn near perfect.

Fourth, open throttle to about 1/5 of full (I use SS20 out of 128).  Again observe the chuff match to the drivers, and adjust CV58 as necessary to get the best possible match between the chuffs and driver rotation. 

Check the chuff/driver rotation at some different throttle settings.  If things seem "off", re-check CV58 at the throttle setting where it seems off. 

You're done.  I've found that this process will produce nearly perfect chuff/driver rotation match up to about 1/3 full throttle (depending on how high you've got max speed set).  After that, you can't really tell whether the match is perfect or not because the drivers are moving too fast.  Call it done; have a beer.  And make sure to SAVE all your settings, including the BEMF settings (CVs 51, 52, 53, 54, 55 and 116-119).

John C.

[tehachapifan]

All great info!

Thanks to all that responded!

It may take me a bit to digest all of it before I attempt any changes.

[RBrodzinsky]

Well this is embarrassing -- these past couple days I've posted a cut/paste of the procedure from the manual, and today I noticed there is an error in the LS 5 manual!   In the LS V4 / Select manual, step 3 had your divide by 0.128, not 4!   0.128 is the correct value to divide by (0.032 x 4). Each unit in CV57 is 32 milliseconds (0.032 seconds) and 4 chuffs per revolution.

The only reason I used the LS 5 manual was the sections were renumbered.   

[trainforfun]

I am in the process of installing a sound decoder in the tender of an LL Y6a ( 15 years old at least ) .
I don't want wires between the loco and tender . So I will put a small DZ126T in the loco and a sound decoder in the tender .
The power pick up in the tender is great having 6 wheels pick up and the loco have 8 driving wheels pick up .
For now the bell , whistle , and other sound works great with the function but I can't get any chuff sound do you think its because the setting is too low or because the decoder does not recognized any motor connected , if so could I add a resistor acting like a load on the motor wires ?

[reinhardtjh]

For now the bell , whistle , and other sound works great with the function but I can't get any chuff sound do you think its because the setting is too low or because the decoder does not recognized any motor connected , if so could I add a resistor acting like a load on the motor wires ?

You are going to have problems with the chuff synchronization and sound characteristics as the LokSound decoder uses BEMF for both.  Without the actual motor load on the decoder motor outputs it has no reference.  Putting a resistor across the outputs will do no good as it won't vary as the load/speed varies.

[trainforfun]

Ok thanks , so I will have only the bell,  whistle and other sound but no chuff unless I install 2 wires to the motor .
Thanks for your answer !!!