I have some 37xx models and have always been impressed with their running qualities, being, in my opinion, better than some with more modern decoders fitted.

I have 3703, 3743, and 3782, and I'm looking to adding some more. I like the 3768 E18, and the 3739 Ae6/6, for example.

The cons I know about don't worry me. These are:

No lights in analogue,
Less speed steps,
All adjustments by DIP switches and pots inside loco body,
No functions except lights.

The pros are:

Smooth linear running characteristics,
Insensitive to poor track contact,
Relatively cheap on the second hand market.

Can anyone advise any other properties of these locos? Do you have any of these, and if so what are your experiences?

Thanks Steven, I had forgotten that you can't switch off the acceleration/braking delay on the 6090 decoder.

I'm surprised you don't find it very smooth at slow speed, as mine are excellent, as good as with a 60901 decoder.

All of my 37XXX locomotives have functioning lighting in either analog or digital mode. I have two older loks (3638 and the crocodile from the 26730 Set) where the lights only work in digital operation. I thought that the switch from 36XXX to 37XXX indicated that this issue no longer applied to the models.
As you stated, these models required that the shell to be removed to alter the settings and worse yet, to switch the locomotive from digital to analog modes. The newer decoders can operate on analog or digital layouts without having to make any changes. Additionally, the new decoders basically enable the companies to produce DC models with mounts for the AC sliders. Adding a slider and a motorola compatible decoder means that these models can easily be manufactured for either AC or DC with minimal added costs (non-isolated wheelsets, decoder and slider).
I have not found any difference in the operation of the new decoders. They respond as well, if not better than the older Maerklin ones. The issue may more be the result of changes in the type of motor (classic motor vs Cardan Drive, etc).
There are of course some changes that I am not a fan of, including the selection of catenary/rails being moved from a externally accessible switch to a contact on a PC board that must be bridged, requiring that the lok be opened to make the change.
The classic Maerklin motors last a long time. As long as you replace the brushes and maintain it properly, they can go on for decades. I am not quite so certain that the some of the modern motors will be as durable.
Living alongside a mainline leading to a freight yard here in Montreal, it is normal that the train cars bunch up when the loks slow down. The compression of the couplers (buffers in Europe) is a very familiar sound.
If you have a first generation 6090 or older 6080 in your lok, you may want to upgrade to the later 6090X decoder. This should solve the lighting (analog) and flickering (digital) issues.

Regards

Mike C

Another difference between the 6090 (c90) and 6090x (c91) decoder is that the last driving direction is monitored continously in the c91 but not in the c90.

The direction change in the c90 is purely based on the direction change data bit change (if running digital), while the c91 constantly monitors the direction bit status. That is if you use a 6081 control unit with DIP-switch 2 "on" (direction arrows operative) or a newer device like the MS or the CS.

Simple test: Drive forwards and stop. Lift the locomotive off the track, switch direction, put the locomotive back on the track and drive.
If the locomotive continues forwards it is a c90, if it drives backwards it is a c91.

Ray,
Your statement, in my opinion is a bit biased.

The locos you've mentioned are suitable for conversion without any trouble.
a.) sensitivity ?
A loco only runs well if the following parts are in order.
1.) have 2 groundwires attached a.) the motor & b.) the chassis.
2.) You will find over time the bogy will loose its contact unless the loco is running frequently.
most metal bogies (non-motorized) have 2 contact lips and they touch the chassis.
the electrical contact between the metal lips and the (white) metal chassis can get corroded. You can bring this section of corrosion back to life with a flat screwdriver by removing the arc buildup.
The screw itself which holds the bogy is not enough to have permanent contact.
There are also locos with bogies whereas Märklin has added a spring washer to it to improve the contact area.

3.) A decoder can make some differences to your running characteristics but most decoders today have these qualities.
4.) The running characteristics can also be hampered by a poorly designed motorshield or brushholder. The brushholder is pressed on by machine and the idea is, the brushholder should be level with the motorshield, in most cases it has lifted up slightly, this causes the brushes to be off an 90° angle, hence a reduction in the smooth and full running potentials.

To compare analog with digital in such a way as to the cons and pros, is in my view, and your reasons given, to some extend, obvious.

If you are a fan of analog, you most probably be never a fan of digital.
My preference lies in digital, regardless of the cost associated with.
The benefits of digital can not be measured or be compared with analog, although todays digital locos can run on analog with some of the digital functions available.

All my SBB Ae 6/6 (6) have been converted with ESU decoders and loksound decoders.
I've also gone a step forward and added ball bearings to the armature shaft on both sides.
I will soon be tinkering with the idea of trying to add a 60901 armature shaft to these locos (originally large flat armature) and instead of adding a 6mm ballbearing (by drilling a hole into the back of motorbogy) using the standard 5 pole armature from a 60901 converwion set and drill a 4mm hole instead.

My intnetion to convert these locos at the time and finding shops who sold these conversion sets cheap without the decoder, made it possible to do so.
Today with ebay, one may ask, is it all worth it, going through with conversions, when some of the locos on the market are so cheap.
You may never get rid of the noise (analog or digital) but the running characterists have definitely improved by 50% (incl. ballbearings).

When I talk about analog, to me it was and is or has been a nostalgic era.
I don't think running characterists become part of the equation.
You excepted how these locos ran, whether noisy, erratic or fast.

I cannot see any problem whatsoever to convert the locos you've mentioned into digital.

Märklin 60901 decoders, for what they are, are too expensive.
There is not another decoder on the market which matches the Märklin price.
You have to ask yourself: Why is this.
For instance the latest ESU decoders Version 3 have a pulse timer setting with your AUX functions. (telexcoupling)
I don't know whether or not the latest mfx decoders can be run on analog with certain functions, e.g. sound
Most other brands have the ability to do so.
I rather see a conversation of digital: the pros and cons of different decoder manufacturers, than comparing digital with analog.
There is sometimes an argument of analog locos can be fixed by anyone, wheras electronically run locos, you can't fix them.
both locos have armatures, the can fail.
coil magnet on analog versus permanent magnet (no failure with pemanent magnet)
reversing unit, can fail. decoders, none have failed so far.
Analog Transformers (outdated) digital components (haven't had any problem with my digital system since 1984.


John

Darrin, Mike, Tom, Svein, Tim (Did I miss anyone out?),

Thanks for your valuable information. I guess I would have to decide whether any of the issues mentioned is a problem for me. Either way, as has also been mentioned, it would be quite easy to upgrade one of these locos to a newer decoder, like a LP3.

I think possibly one of the reasons I don't see a big difference is that I run them with a 6021, which has fewer speed steps.

Now I have to decide, do buy one of these gorgeous older locos or not...and if so, which one?

Ray,
The problem I have with 6090 (don't have any of them anymore) 60901 is, the speedsteps as mentioned my Thomas, aren't enough for my sidings to bring the train to a halt at reasonable speed, with other words, the speed steps are to low to go all the distance without haveing the train or loco racing into the siding.
ESU lokpilot Versions will give you the extra lenght at low speed.
You may have noticed on my videos some locos are running faster than others and this is the reason behind it, to get into the siding, brake and activate a switching track and stop before the signal.

John

One of the annoyances with the 6090 is that the PWM frequency of the motor drive is still around 80-90 Hz as the c80 was, while the newer LokPilots, M mfx decoders and such drive the motor with somewhere around 16-20 KHz which gives much smoother operation an much less noise... The old 6090 is not suitable at all with eg Faulhaber motors since the lower PWM frequency will destroy them... The newer high PWM frequency decoders will work fine with Faulhabers and other can motors since the motors see it as "almost pure DC"... The 6090 was designed for the 5***** DCM motor that came in the later 1990's, but these motors run much more silent with a higher frequency PWM too - as clearly shown with the mfx + 5***** models...

And the fantastic feature of having lights off in analog mode with 6090 is of course also a showstopper for many...

So, I'd say - if you can afford it - upgrade from the the 6090 decoder to LokPilot 3 or higher, 60901 will do too, or M mfx decoders - so you at least can get the full benefit of both the MM2 command station protocol (directional bit in the datastream) as well as additional decoder features... And - lights are on in analog too with anything above 6090....