Author Topic: Bachmann Spectrum Decoders....  (Read 725 times)

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sizemore

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Bachmann Spectrum Decoders....
« on: December 21, 2010, 10:01:20 AM »
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I know that Bachmann is making decoders in house from Lenz plans IIRC, but my question concerns the speedsteps. The 44T was only 28, does the new GP7 and Consolidation have a 128 speedstep decoder?

The S.

sizemore

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Re: Bachmann Spectrum Decoders....
« Reply #1 on: December 23, 2010, 01:21:35 PM »
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...crickets crickets...

93cram

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Re: Bachmann Spectrum Decoders....
« Reply #2 on: December 23, 2010, 03:57:02 PM »
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Dear Mister 'the S',

My (admittedly very limited  ;D) understanding of current DCC technology is that 28 and 128 speed steps are actually derived one from each other, the higher being a sort of 'fractioning' of the basic 28 speed steps range, to give finer control.
Mostly deals with throttle rather than decoder configuration if I'm not mistaken.
If the decoder supports 28 speed steps, you can go 128 if your throttle/command station support 128 speed steps (guess very few doesn't today)

Hum, time to dive into my foxhole I guess  ;D)

Marc  ;)

sizemore

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Re: Bachmann Spectrum Decoders....
« Reply #3 on: December 29, 2010, 09:13:56 AM »
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Dear Mister 'the S',

My (admittedly very limited  ;D) understanding of current DCC technology is that 28 and 128 speed steps are actually derived one from each other, the higher being a sort of 'fractioning' of the basic 28 speed steps range, to give finer control.
Mostly deals with throttle rather than decoder configuration if I'm not mistaken.
If the decoder supports 28 speed steps, you can go 128 if your throttle/command station support 128 speed steps (guess very few doesn't today)

Hum, time to dive into my foxhole I guess  ;D)

Marc  ;)

I believe you are referencing status editing on the throttle. This means the throttle will throw out commands at 128 resolution (really just bits), but the decoder will still operate at 28 speedsteps.

The S.

93cram

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Re: Bachmann Spectrum Decoders....
« Reply #4 on: December 29, 2010, 11:08:25 AM »
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I believe you are referencing status editing on the throttle. This means the throttle will throw out commands at 128 resolution (really just bits), but the decoder will still operate at 28 speedsteps.

Yep, but again I may be wrong  :-[
Just that with CV29, you can't discriminate between 28 and 128 speed steps, just between 14 and 28/128  :-\
Perhaps my decoders are badly configurated or I'm a poor DCC runner  ;D, but I can't see any difference in speed
with the same engines at step 1, between the 28 speed steps setting and the 128 steps setting.
Of course, above speed step 1, acceleration is much quicker (momentum settings notwithstanding) with 28 steps than with 128  ;D
FWIW, I understand the 128 speed steps as a kind of 'built in throttle inertia' if it does make sense  :)


sizemore

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Re: Bachmann Spectrum Decoders....
« Reply #5 on: December 29, 2010, 12:18:33 PM »
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Of course, above speed step 1, acceleration is much quicker (momentum settings notwithstanding) with 28 steps than with 128  ;D
FWIW, I understand the 128 speed steps as a kind of 'built in throttle inertia' if it does make sense  :)

You've proven that the decoder is only running at 28 speed steps even though the throttle is pushing out 128 step signal by pointing out the accelleration/speed curve is different (i.e. acceleration is quicker). Therefore without setting any momentum or adjusting the speed curve, I am losing those other ~100 speed steps which really make a difference in slow speed operation. Back to my original post I want to know if the OOTB decoders in the newest Bachmann releases (70T, GP7 and Consolidation) are 28 step or 128 step, for that very reason. If you use momentum in the Heavy Mountain the momentum will work however it will noticeably jump when it reaches a speed step which is very unrealistic.

The S.

93cram

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Re: Bachmann Spectrum Decoders....
« Reply #6 on: December 29, 2010, 01:29:04 PM »
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S,

Does the B-mann heavy Mountain's decoder supports Back-EMF ?
Just found out this afternoon while playing with my Digitraxx F and FT decoders settings that lowering the B-EMF (from default 6 to 4, 3 or 2) would somewhat improved (smoothed out) speed at lower steps (nominally step 1 and 2).
Problem is that operations at speed step 1 are different whether engines run light or with 20 bad rolling, plastic wheels equipped cars trailing  ;D ;)
so what works for one situation doesn't necessirally work for an other.

Marc

sizemore

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Re: Bachmann Spectrum Decoders....
« Reply #7 on: December 29, 2010, 02:28:42 PM »
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S,

Does the B-mann heavy Mountain's decoder supports Back-EMF ?
Just found out this afternoon while playing with my Digitraxx F and FT decoders settings that lowering the B-EMF (from default 6 to 4, 3 or 2) would somewhat improved (smoothed out) speed at lower steps (nominally step 1 and 2).
Problem is that operations at speed step 1 are different whether engines run light or with 20 bad rolling, plastic wheels equipped cars trailing  ;D ;)
so what works for one situation doesn't necessirally work for an other.

Marc

Yes a lower BEMF value will improve lower speed operation but BEMF isn't an equalizer for speedsteps, in slow speed operation.

The S.




93cram

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Re: Bachmann Spectrum Decoders....
« Reply #8 on: December 29, 2010, 02:57:41 PM »
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Yes a lower BEMF value will improve lower speed operation but BEMF isn't an equalizer for speedsteps, in slow speed operation.

FWIW, Digitraxx (and TCS ?) offer some further tweaking of BEMF settings with CV#56 and 57.
From what I've understood, those CV are supposed to address 'speed jump(s)'  ??? ;)

sizemore

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Re: Bachmann Spectrum Decoders....
« Reply #9 on: December 29, 2010, 03:31:15 PM »
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FWIW, Digitraxx (and TCS ?) offer some further tweaking of BEMF settings with CV#56 and 57.
From what I've understood, those CV are supposed to address 'speed jump(s)'  ??? ;)

Yes they help smooth out the speed from one step to the next but I get a much more linear acceleration with more speed steps or "jumps". But again BEMF does not help speed resolution. I'd rather have a decoder with 128 speedsteps + BEMF versus a 28 step decoder + BEMF.  ;D

The S.

Mark5

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Re: Bachmann Spectrum Decoders....
« Reply #10 on: December 29, 2010, 03:38:28 PM »
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<watching and taking notes>