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will higher start voltage of a dcc sound engine make itrun better at very slow speed?

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Posted by gregc on Wednesday, August 19, 2020 6:12 AM

MRC tech 2500

is PWM

http://cs.trains.com/mrr/f/744/p/269380/3053917.aspx#3056485

(i put the above link between <url> </url> tags, replace < with [)

greg - Philadelphia & Reading / Reading

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Posted by ATLANTIC CENTRAL on Wednesday, August 19, 2020 6:16 AM

rrebell

I guess the only way is if I used the exact same engine. That will not happen and after futher testing of just DCC engines, I have two exact ones of the same engine, one runs twice as good as the other and I can find no diferences that would make it so.

 

DCC locos are subject to all the same mechanical variations that make any two DC locos run different. PLUS, they have those pesky decoders that can have different CV settings. 

In theory two new out of the box identical DCC locos should have the same CV settings and run the same.........

But manufacturers do sometimes change decoder suppliers, change base line CV settings, settings get changed by shop owners before the sale, or with used locos you have no idea who has reset CV settings..........

So until you check that, again all comparisons are worthless.

Sheldon

    

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Posted by tstage on Wednesday, August 19, 2020 6:18 AM

gregc
MRC tech 2500

is PWM

http://cs.trains.com/mrr/f/744/p/269380/3053917.aspx#3056485

Let's make that link clickable:

http://cs.trains.com/mrr/f/744/p/269380/3053917.aspx#3056485

https://tstage9.wixsite.com/nyc-modeling

Time...It marches on...without ever turning around to see if anyone is even keeping in step.

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Posted by gregc on Wednesday, August 19, 2020 6:24 AM

tstage
Let's make that link clickable:

how?

greg - Philadelphia & Reading / Reading

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Posted by ATLANTIC CENTRAL on Wednesday, August 19, 2020 6:28 AM

gregc

MRC tech 2500

is PWM

http://cs.trains.com/mrr/f/744/p/269380/3053917.aspx#3056485

(i put the above link between <url> </url> tags, replace < with [)

 

Well, by that description it is cheap and dirty 60Hz PWM at best.

I have not scoped any of them, I am only going by their own description.

In any case, the OP now understands that his comparison was not valid in the first place.

And I have no dog in this fight since I am happy with my Aristo PWM throttles which have a high frequency PWM output similar to a DCC decoder and work great.

I may have a Tech 2 2500 laying around here, a friend gave me a bunch of power packs when he converted to DCC years ago. If I am correct, my recollection of its performance is not anywhere near as good as the Aristo Train Engineer, which of course is also wireless radio.

Sheldon 

    

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Posted by richhotrain on Wednesday, August 19, 2020 6:39 AM

gregc
 
tstage
Let's make that link clickable: 

how? 

You shouldn't have to do anything to make such links clickable, but the finicky nature of the forum won't let you do it without modifications. And, when you try to do it with modifications, the finicky forum software wants to modify the modifications.

Rich

Alton Junction

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Posted by tstage on Wednesday, August 19, 2020 6:39 AM

gregc
tstage
Let's make that link clickable:

how?

Greg,

I copied your URL link, pasted and opened it in a new tab in my browser (Firefox), copied that URL link (again), then created the link as you described.  I've found that copying the URL directly from someone else's post and creating a link from that doesn't work on this forum. Tongue Tied  So, I copy & paste it in a new tab, copy it from that, then insert it between bracketed urls in the text body of my post.

Tom

https://tstage9.wixsite.com/nyc-modeling

Time...It marches on...without ever turning around to see if anyone is even keeping in step.

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Posted by ATLANTIC CENTRAL on Wednesday, August 19, 2020 6:56 AM

A few more thoughts:

I think MRC knows that TRUE high frequency PWM will not work with dual mode DCC decoders.

Their market for DC power packs requires DCC dual mode decoder compatiblitly.

They are trying to get the best DC control they can without loosing that market segment.

If you put a dual mode decoder DCC loco on my layout with my Aristo throttles, one of two things happen, it has two speeds, full speed on and off, OR it sits there and buzzes, because the decoder is confused by the high frequency pulse of good PWM. Testing of more than a dozen different DCC locos has always had one of those two results.

MRC has made it clear that the "DC to DCC transitional market" is important to them, with their dual mode packs that cost as much as DCC starter systems....... 

Sheldon

 

    

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Posted by rrinker on Wednesday, August 19, 2020 8:48 AM

 Ernst seems to no longer be around, Walthers lists them but it's all out of stock. Searches find nothing but some forum posts of people complaining they were loud - they just didn't installt hem correctly. I had an S12 I put a set in. The trick was to use tooth polish, like Pearl Drops, to lap the gears, run it a while in both directions, then take it all apart and clean it out, then reassemble with proper lubricant. Witht he worms off, my loco would roll on smooth surfaces rather than slide, even with all those extra gears. Standard Athearn BB motor tune up technics quieted the motor. That thing could pull anything I tried, and ran at a nice realistic top speed, and quieter than it came out fo the box. Having the motor and flywheel RPM higher for a given speed of the loco makes it more likely to coast over dead spots, and allowing a higher voltage for a given ground speed makes for smoother starts, so there definitely advantages to gearing down fast running locos. 

 But if the loco already runs at realistic speeds, the only way to improve performance is to reduce as much as possible any friction in the drive line, and use a power source most conducive to getting the motor to turn over as slow as possible while not stalling.

 Remember the Tech II 2500 is some 40+ years old. I got my 1500 for my N scale layout around 1978. There was no DCC dual mode to worry about - it was more MRC building to a price the market could support. You can see it in the disassembly shots, and other brands aren't any better. They aren't exactly finely crafted devices with lots of attention to detail. But people weren't going to pay $100+ for a single throttle power pack.

                                       --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by SeeYou190 on Wednesday, August 19, 2020 8:59 AM

This is hllarious...

We had two seperated conversations, both spiralling down in this thread.

Tom asked us to only talk about one of them.

Then we started talking about Ernst Gears, clickable links, and Tech II 2500 power packs.

At least the conversation has become civil and not full of bad information.

-Kevin

Living the dream.

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Posted by ATLANTIC CENTRAL on Wednesday, August 19, 2020 9:06 AM

SeeYou190

This is hllarious...

We had two seperated conversations, both spiralling down in this thread.

Tom asked us to only talk about one of them.

Then we started talking about Ernst Gears, clickable links, and Tech II 2500 power packs.

At least the conversation has become civil and not full of bad information.

-Kevin

 

Well agreed, but the Tech 2 converstation relates directly to the OP's question, since that is the DC power pack he is using to formulate the comparison he asked about.

Sheldon

    

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Posted by ATLANTIC CENTRAL on Wednesday, August 19, 2020 9:09 AM

rrinker

 

 Remember the Tech II 2500 is some 40+ years old. I got my 1500 for my N scale layout around 1978. There was no DCC dual mode to worry about - it was more MRC building to a price the market could support. You can see it in the disassembly shots, and other brands aren't any better. They aren't exactly finely crafted devices with lots of attention to detail. But people weren't going to pay $100+ for a single throttle power pack.

                                       --Randy

 

I should have been more clear, I was refering to the fact that MRC has yet to build a true high frequency PWM throttle.

Sheldon

    

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Posted by ATLANTIC CENTRAL on Wednesday, August 19, 2020 9:29 AM

Lastspikemike

 

 
ATLANTIC CENTRAL

A few more thoughts:

I think MRC knows that TRUE high frequency PWM will not work with dual mode DCC decoders.

Their market for DC power packs requires DCC dual mode decoder compatiblitly.

They are trying to get the best DC control they can without loosing that market segment.

If you put a dual mode decoder DCC loco on my layout with my Aristo throttles, one of two things happen, it has two speeds, full speed on and off, OR it sits there and buzzes, because the decoder is confused by the high frequency pulse of good PWM. Testing of more than a dozen different DCC locos has always had one of those two results.

MRC has made it clear that the "DC to DCC transitional market" is important to them, with their dual mode packs that cost as much as DCC starter systems....... 

Sheldon

 

 

 

 

Hmm. That's very interesting. My Tech 7 powerpacks seem to operate exactiy that way. The Tech 6 "dual mode" on the other hand does not seem to. Current DCC decoders run the same in DC or DCC  on the Tech 6 but older ones definitely do not. Mind you the whole point of the Tech 6 is you don't need to have the capability to run DCC in DC mode. 

 

You keep saying this about how "current" or newer decoders work. But have you exhuastively tested all the decoders currently on the market?

And so what if the new ones do work better on DC than the older ones? People are just supposed to throw away all their older DCC locos and buy newer locos so they can run them on DC?

No offense to ANYONE, but I will suggest again, just go DCC or stay DC, being on the fence is full of pitfalls.

I know how the Tech 6 works........

And I know how dual mode decoders do not work on true high frequency PWM DC.

I have 140 locos, and no decoders..........

All my trains run fine. I run 3-4 unit diesel lashups, I double and triple head steam locos of different wheel arrangements from different brands. My headlights come on before my trains move, and I walk around with a wireless throttle in my hand - all without DCC.

I run 4 trains on a double track mainline, and I don't flip any block toggles........

I seriously considered DCC several times, rejected it every time. But for most peoples needs, DCC is the best choice.

Sheldon

    

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Posted by SeeYou190 on Wednesday, August 19, 2020 9:34 AM

ATLANTIC CENTRAL
I will suggest again, just go DCC or stay DC, being on the fence is full of pitfalls.

Yes +1

Either DCC do yes or DCC do no or else squished, just like grape.

-Kevin

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Posted by rrinker on Wednesday, August 19, 2020 9:54 AM

 "Older" is not particularly descriptive. The earliest DCC decoders often did not support running on DC. At all. For example, early Atlas Gold DCC locos had a jumper plug on the board, in one position, it was DCC, in the other, DC. Because the decoder couldn't run on DC. Early sound decoders also did not work on DC. At all. 

 Even with DCC decoders that CAN run on DC - they can be configured to not respond to DC. 

 And DCC motor only decoders that work on DC behave completely differently than DCC+Sound decoders that will work on DC, for reasons previously explained with regards to voltage and making the sounds work.

                          --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by rrebell on Wednesday, August 19, 2020 10:24 AM

ATLANTIC CENTRAL

 

 
gregc

MRC tech 2500

is PWM

http://cs.trains.com/mrr/f/744/p/269380/3053917.aspx#3056485

(i put the above link between <url> </url> tags, replace < with [)

 

 

 

Well, by that description it is cheap and dirty 60Hz PWM at best.

I have not scoped any of them, I am only going by their own description.

In any case, the OP now understands that his comparison was not valid in the first place.

And I have no dog in this fight since I am happy with my Aristo PWM throttles which have a high frequency PWM output similar to a DCC decoder and work great.

I may have a Tech 2 2500 laying around here, a friend gave me a bunch of power packs when he converted to DCC years ago. If I am correct, my recollection of its performance is not anywhere near as good as the Aristo Train Engineer, which of course is also wireless radio.

Sheldon 

 

I have a box of those left over from a club along with a set of ones from their onboard HO set ups and lots of decoders for that one. The Train Engineer stuff.

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