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Re-enginged A Class vs 071 engine sound

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Listening to videos of both of these locos there is a distinct whine with the 071 as compared to the more gutteral sound of the A. Both had (by the mid 90s) the same basic prime mover in the 12 cylinder 645. Is the difference just a turbo in the 071s or something more?

There seem to be T and NT versions of this engine's sound on the ESU site. I am assuming this stands for turbo and non-turbo (rather than the more usual "normally aspirated" terminology). These files seem to correspond to the real thing insofar as the T version sounds like an 071 while the NT version sounds like the A.

Edited by murphaph
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The turbo is what gives the 071 the distinctive whine, but the real answer gets a little more complicated! The A class has a very different exhaust system to any of the EMD locomotives that use the non turbo 645.  If you listen to any of the EMD locos you'll find they all sound pretty similar regardless of the number of cylinders in the prime mover. There really is no prime mover in the ESU library that matches it. I made a soundfile for my kit-built A class which used an older non turbo 567 which had a very unusual low growl to it. I've actually forgotten which file I took it from! 

To be honest I'll probably end up purchasing the bespoke decoders from IRM for my A classes when they arrive.

Edited by irishthump
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"A"s are Roots-blower, mechanically supercharged, 071s are turbocharged.

With mechanical supercharging, the speed of the engine directly effects the supercharging, with turbocharging it is the load on the engine instead.

 

This is taken from the article in IRRS Journal 074

 

 

Edited by hexagon789
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3 hours ago, irishthump said:

The turbo is what gives the 071 the distinctive whine, but the real answer gets a little more complicated! The A class has a very different exhaust system to any of the EMD locomotives that use the non turbo 645.  If you listen to any of the EMD locos you'll find they all sound pretty similar regardless of the number of cylinders in the prime mover. There really is no prime mover in the ESU library that matches it. I made a soundfile for my kit-built A class which used an older non turbo 567 which had a very unusual low growl to it. I've actually forgotten which file I took it from! 

To be honest I'll probably end up purchasing the bespoke decoders from IRM for my A classes when they arrive.

Nail on the head. The A Class exhaust system is pretty basic in that there's essentially three holes in the roof for the three exhaust manifolds to release gases and fumes through - nothing more complicated than that! It certainly did give them a distinctive sound in comparison to other EMD-engined locomotives.

We will have an update in the next few weeks that include a sound demo, which we're excited for everyone else to hear... ;) 

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I can't wait to hear that demo. One thing I'd really like is the ability to obtain a sound project from IRM by email, locked to a particular decoder.

Some sound project businesses do this where you give them the serial number of the decoder along with the payment and they email you a locked file that will only work in that decoder. There are no postal costs/risks. Completely digital business. 

Failing that, I would also be happy if I could buy the physical IRM decoder but receive a backup sound project locked to that particular decoder.

Why? Because I want to be able to play around with my decoders without fear of losing an irreplaceable sound file through a false click. I can back up the settings stuff but not the sound part.

Please at least bear these options in mind for the future 😉 I'm aware that there is an overhead involved but IRM could put in a disclaimer that once the file is emailed it's up to the owner to back it up in a safe place and that IRM will not provide endless backups to careless owners.

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21 hours ago, murphaph said:

Maybe I'm tone deaf but the ESU v5 file for the 12-645 NT variant sounds close enough to the A for me!

It certainly has that throaty growl.

I haven't really listened to any of the V5 files, but if it sounds good enough for you then use it!

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9 hours ago, murphaph said:

I can't wait to hear that demo. One thing I'd really like is the ability to obtain a sound project from IRM by email, locked to a particular decoder.

Some sound project businesses do this where you give them the serial number of the decoder along with the payment and they email you a locked file that will only work in that decoder. There are no postal costs/risks. Completely digital business. 

Failing that, I would also be happy if I could buy the physical IRM decoder but receive a backup sound project locked to that particular decoder.

Why? Because I want to be able to play around with my decoders without fear of losing an irreplaceable sound file through a false click. I can back up the settings stuff but not the sound part.

Please at least bear these options in mind for the future 😉 I'm aware that there is an overhead involved but IRM could put in a disclaimer that once the file is emailed it's up to the owner to back it up in a safe place and that IRM will not provide endless backups to careless owners.

You can't lose or delete a soundfile by messing around with the decoder settings either with the Lokprogrammer or by manual programming on the layout. You can alter CV's which may affect the way the sounds operate but these can be restored by a reset, this doesn't affect the loaded soundfile, contrary to what many people seem to think.

That said I would also like to see IRM and Murphy Models at least consider trying to supply the files to customers if it's at all possible.

 

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4 hours ago, murrayec said:

There is a note in Mr Murphy's 121 instructions 'use of a non MM chip voids the loco warranty' one should keep that under consideration when using non MM chips.....

Eoin

I really don't understand that, there's almost no way that using another brand of decoder can cause damage to a loco. What's far more likely is faulty wiring in a loco causing damage to a decoder! 

A DCC ready loco should operate with ANY decoder without fear of invalidating a warranty.

Edited by irishthump
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  • 2 weeks later...

Lots of companies used 'proprietary' hardware and software essentially to ensure they maximize their bottom line, that's nothing new.

If you use something else, then that may invalidate any warranty provided as part of the purchase agreement. This may be contingent on local statutes in the country of purchase.

If you go off label because it's cheaper or you want a different sound is up to the purchaser but if you do have a problem you're likely to find that the vendor will likely not be very accommodating of your request for a replacement (if available!) or a refund. You could litigate but would you want to bother?

I will say that generally I dislike this approach re use of 'proprietary products' and don't think it does much in the longer term for the vendor (unless you're don't plan any future products, I suppose)  

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5 hours ago, DiveController said:

Lots of companies used 'proprietary' hardware and software essentially to ensure they maximize their bottom line, that's nothing new.

If you use something else, then that may invalidate any warranty provided as part of the purchase agreement. This may be contingent on local statutes in the country of purchase.

If you go off label because it's cheaper or you want a different sound is up to the purchaser but if you do have a problem you're likely to find that the vendor will likely not be very accommodating of your request for a replacement (if available!) or a refund. You could litigate but would you want to bother?

I will say that generally I dislike this approach re use of 'proprietary products' and don't think it does much in the longer term for the vendor (unless you're don't plan any future products, I suppose)  

Except in this case there is nothing proprietary about the decoder or the software used on it.

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