Yes.
Make sure to use a modern transformer 6647, 6647x, 6646 with modern digital locos.
Don't use Märklin transformers with a metal case.

And welcome to the forum.

In my experience, modern digital locos outperform pure analogue locos.
However, a digital controller is required to change settings of a digital loco for analogue operation. Analogue operation is normally enabled ex works, but it is possible to tweak the settings.

You can set the starting voltage of a loco to e.g. 6 V.
Then at 5 V, you will see the lights and maybe even hear the engine sound, but loco will start moving at 6 V.

so can a 6627 be used for digital locos or is that also one that can fry the electronics?

Reply from Chris: many thanks for this very helpful advice

Very helpful advice, thank you

The nominal reversing voltage of a 6647 is 24 V. I measure 25 or 26 V on mine.
The specification of many decoders only allows 28 V.

One of my blue transformers has 31 V reversing voltage - while a nominal reversing voltage of only 23 V is given.

Hi, thanks for helpful info. Is a blue plastic Trafo 37540 (included in a starter set) seen as an older transformer, so not recommended for digital locos? - is the max voltage for reverse the issue? With thanks, Chris

Hi Henrik

Many thanks for kindly sharing this info - your electronics know-how is much appreciated. I'm waiting for a newer white trafo also, but in the meantime thought I would ask about the current blue 37540 to be on the safe side.

Thanks again, Chris

Great, Paul, many thanks for sharing your experience and knowledge, very helpful. Interesting to see from your post that you're committed to analogue - so far, I've not caught up with digital Marklin, since not progressing from the 1960-70s. Let's hear it still for LPs too....

Regards, Chris

Hi Paul,

As one of the members of the minority, I can only confirm.
I have only 10 locs, but all good old style analog ones, and all on M-rails!


I just enjoy riding them using classic old blue transformers, and some classic automatics with relays...

Minority or not, I enjoy the playing...
Kind regards,
Herman

Hi Paul, thanks so much for sharing your experience, and great to hear your Marklin trainset is fun again. Very heartening that you're able to run your trains with so much enjoyment.

Regards, Chris

I converted to digital as i enjoy the tinkering part of our hobby. The wonderful clicketyclack sound of running M track is fun either way.
Ben

Hi Chris,

Transformers with little power (as your 10VA transformer) often give higher tensions at low charge than do the big 30VA models. So, there is a higher risk with small transformers than with big ones. There is, also, a risk that gets higher and higher the longer you hold the inversion impulsion - good old analogicalists tend to do it longer since some relay inversers needed more time to invert correctly...

On the other side, it's nonsense to pretend that white transformers are "no risk". They function on the same principe as the older models, a weak character makes that on normal charge (30VA for a 6647 or other white models) the inversion tension is 24V and the max normal tension about 16V. With low charges, the tension is higher, and there is no limitation included! So I did kill a decoder with a 6647 transformer !

Test your transformer, and do the test several times at different hours in the day, since the tension furnished by your furnisher depends on the charge, too. Some systems have lower tension on high charge, some raise the tension when charge is high, so as in winter when many people heat the house by electric radiators, or at some time on the day when many machines work in the fabrics. You have to test your secondary tension (0-B when giving inversion courant) at several times a day and on the week-end. If you are sure the tension is never above 24V, no problem. Otherwise... you better look for other solutions.

Exception: old decoders with micro-switch programmation are safe to all transformers.

So, I separate analogical system from all digital locos except the ones with micro-switch programmation. Digital locos on digital command, analogical locos on analogical command. That's the safest way.

Hello all,

I don't know if this is interesting, but here is my experience - though I run only analog - and apparently those older analog locs can handle high(er) voltages.
A while back I started again with these 40+ year old locs and transfos.

Everything seems te work fine, the speed, the switching, and then I started measuring the voltage:
I registered:
Maximum on the red/brown circuit: up to 20V
Switching on the red/brown circuit: up to 32.7 !!!
Light circuit (yellow/brown): 30.8V

So I was concerned, even for my analog locs... (imagine using a digital loc with these voltages)

Viewing several optioins, I choose to use a regulator..



This allows me to regulate the voltage to my transfo's...
Renewed measurements: 15.9 maximum on red/brown, 16V on the light circuit (yellow/brown), but still between 25.3 and 25.9 switching on red/brown - depending on the transfo.

A long story short: measure before going into live setup.
Kind Regards,
Herman

Not correct, the number of windings on the secondary side are different, fewer windings on the reverse impulse part of the 6647 - but of course, if you try hard enough, even a 6647 can destroy things, however quite unusual to destroy a normal Märklin decoder.

Per.

That is a very good point by Tom above.
Last night I measured the mains voltage where I live. It was 241 volts. So that is 4.7% higher than the nominal input voltage of my 6647 White transformers.
I measured the reversing pulse with a digital locomotive on the track and it was 25.1 volts. So that is 4.5% high which is consistent with the higher input voltage.

So the output does vary slightly depending on the input voltage.
It just shows that it pays to be careful even when using the white transformers. Hopefully my 25.1 volts isn't so high as to fry anything.

The mains voltage should nominally be 230 volts +10% or -6% (according to Google) so it can vary by quite a bit - mine falls within this range but it does pay to measure the voltage of the reversing pulse that is actually appearing on your track. I would hope that Märklin would have taken this variation into account when designing their circuits.

That's good to know Tom thanks.
From what I can remember (school was a long time ago) you multiply the AC voltage by the square root of two to get the peak voltage of the sine wave.

Many thanks for these further helpful details. Regards, Chris

I just checked the datasheet for 1n4001 diodes. The diagram starts at 10 mA and then the voltage drop is already around 0.7 V.
So assuming the current drawn by a decoder is around 20 mA, it is probably safe to assume that each diode will "eat" 0.7 V.
I was afraid the voltage drop would be much lower with small currents, but that is not the case here.
Sorry for the confusion.

I think the "square root of two" applies here, too. I would calculate the number of diodes needed bases on the peak voltage, not the efficient voltage.