Bachmann 37 Sound

[kiwitrains]

I have a 21 pin sound decoder for the Bachmann Class 37 I would imagine the wires from the speaker go to the Sp connectors on the PCB board if so does it matter which way round. Does the fan have to come out or just the cover it is the latest model i.e. 21 pin.

[ailsa]

I have a 21 pin sound decoder for the Bachmann Class 37 I would imagine the wires from the speaker go to the Sp connectors on the PCB board if so does it matter which way round. Does the fan have to come out or just the cover it is the latest model i.e. 21 pin.

 

I recently installed a 21pin Loksound decoder into a Bachmann 37 that was not previously sound fitted.

 

You are correct that the speaker connects to the SP terminals on the PCB. It doesn't matter which way round, it will work either way.

 

I don't know about the fan - I mounted the speaker in the bottom of the fuel tank having drilled an array of holes to let the sound escape. Routing the speaker wires was difficult as they wanted to interfere with the flywheel. All was sorted in the end, though I did cut a little away from one of the cab bulkheads to make it go together a bit easier.

[adge-peanuts]

I have been retro fitting my 23 mm speakers in the fuel tanks,and have found the they will fit in speaker upwards.

 

Which means not having to start drilling holes in the tanks.

 

The sound still escapes just as well as before,some people have said it sounds better but to my ears they are as good.

 

I find feeding the wires along side the motor and feeding it round and into the hole in the chassis side that is provided seems to work fine,although you do need to help the tumblehome on the body over it to get the body on.

 

The fan can remain with this fitting method.

 

Hope this helps

[Pete Harvey]

Quietly in the background I have been working on a base box designed just for the class 37 that anyone can build and I have come up with the attached I have built and fitted one already to a class 37 with great results here is a videos for you to hear the difference your selves.

 

Sound box assembly drawing Base Box Assembly.pdf

 

Here we go from the top.

 

The things that you need for this little exercise.

 

Stage 1,

 

Stage 2, When cutting the Discs Do Not cut with the blade turn the blade around

and use it to scribe cut the discs,this way the blade will not wander and you will get a good circle every time.

 

 

Stage 3, Mark a strip 23mm wide the length is not that important but it must not bee very short.

 

Stage 4, All of the parts that you need.

 

Stage 5, Mark up the large disc as show here.

 

Stage 6, Remove the sections as shown above.

 

Stage 7, Mark up the strip as shown, I made a mistake here the 24mm measurement should be 25mm

and the small strips are 1mm spaced.

 

Stage 8, Mark out the circles as shown here I used the disc cutter as it was an easy way to do it,

drill 14 1mm holes.

 

Stage 9, All of the parts cut and ready for assembly.

 

Stage 10, Using MEK fix the ring to the 25 x 23mm piece with the holes in it then fix one end piece

to the 25mm long side of the piece with the hole in it and then do the same with the other end.

 

Stage 11, glue two of the 1 x 23mm strips to the underneath as shown above.

 

Stage 12, Now take the 25 x 23mm piece as shown above and fix it to Stage 11 so that it looks like the above.

 

Stage 13, now drill two 1mm holes as shown on the drawing for the wires to pass through, un-solder the

speaker wires pass the through the two holes and reconnect to the speaker, use contact adhesive on

the speaker only and fix it to the ring and your done.

 

I used Black Tak to fix the bass box to the chassis then if I want to change to a different loco in the future I can,

I painted the Bass Box and shiny parts of the speaker matt black.

It fits perfectly in a 21pin chassis you may need to do some trimming as I did to get it to fit on an 8pin chassis, but

do not cut the bottom to get it to fit as it will wreck the sound that comes out trim the curve on the top,

oh and remove the screw that hold the circuit in place.

 

Remove the old fan mounting screw hole.

 

 

I have found since posting this originally in the old forum that if the speaker is covered completely the sound is greatly amplified.

 

Here is a video of the improved version of the class 37 sound box I'm sorry about the picture quality but the sound quality is good.

http://s119.photobucket.com/albums/o153/PeteH_2007/?action=view&current=Geoffs37Sound.flv

 

 

Have fun building this?

 

Pete

[Piemanlarger]

have you compared your base box to a 37 fitted with base reflex Peter?

[Pete Harvey]

Yes I have and they are about the same mine seams to be just a little crisper in the sound quality it sound very good in a big hall as well as those that went to the Peterborough show can tell you.

 

Pete

[Piemanlarger]

Yes I have and they are about the same mine seams to be just a little crisper in the sound quality it sound very good in a big hall as well as those that went to the Peterborough show can tell you.

 

Pete

 

ok thanks, if you ever produce the base box for sale let me know. Not got a great deal of time to build one at the moment.

[Bruce Depot]

as a fall back you could try using Blue tack, I have used it in most of my sound

fitted locos for boxing in etc with great sucess....

 

regards

 

Keith

[Will Vale]

The speaker enclosure looks very good, thanks for posting such detailed instructions. I might well have a go.

 

I did the halfway-house thing of sealing up the Bachmann enclosures on my 37 and 66 with blu-tak, and was pleasantly surprised, particularly on the 66 which went from sounding terrible and distorted to really quite acceptable.

 

 

[lmnp]

Quietly in the background I have been working on a base box designed just for the class 37 that anyone can build and I have come up with the attached I have built and fitted one already to a class 37...

 

Pete

 

Hi,

 

I know this thread is long dead, but I've just put one of these boxes together. I haven't yet fitted my speaker to it as I ran out of electrical solder to fix the wires so I haven't tried it. But I was wondering why the box design doesn't enclose the back of the speaker. Isn't the idea to try to stop sound interference between the front and back of the speaker?

 

I'm not an expert on sound as you can probably gather.

 

Cheers

 

Richard

[Lady_Ava_Hay]

Hi,

 

I know this thread is long dead, but I've just put one of these boxes together. I haven't yet fitted my speaker to it as I ran out of electrical solder to fix the wires so I haven't tried it. But I was wondering why the box design doesn't enclose the back of the speaker. Isn't the idea to try to stop sound interference between the front and back of the speaker?

 

I'm not an expert on sound as you can probably gather.

 

Cheers

 

Richard

 

This type of enclosure does prevent a good percentage of the sound mix that causes that terrible hissing.

 

I have not built one of these.

 

I have yet to find a personal solution that does not involve using the ESU supplied enclosure and, as a previous post suggests, making sure it is sealed with Blu Tack.

 

The same applies to the bass reflex speaker in that the increase in quality is a bit marginal.

 

At the same time, what a suitably enclosed speaker points at is also relevant as is the fitting of a front baffle and a horn.

 

As always it is the space requirement that dictates. One cannot expect huge quality improvements as the sound file itself is very lo-fi anyway but ANY enclosure is considerably better than NO enclosure and a well fitted and sealed enclosure is much better than a non sealed one.

 

A speaker that is fitted in a tender on a plate that divides the tender in half horizontally will negate the need for any enclosure. If you play that same speaker fitted to the smae plate away from the tender the sound quality is reduced by 75 per cent unless of course you stick it on a transformer grill when the sound quality rockets upwards........

 

The experiments continue but above all it is the space available that dictates.

[Pete Harvey]

Since producing the sound box shown above almost a year ago, I have started to cover the back of the speaker so that it is fully enclosed this does improve the sound quality no end and the Shenker class 37 in Dave's videos has a fully enclosed sound box fitted.

 

The easiest way to do this is to use some .5mm plasticard cut a strip the width of the sound box fix it at one side of the sound box with MEK let that go off then shape it over the sound box and fix it use some elastic bands or weights to keep it in place until it is set.

 

Oh but remember to fit the speaker and wire it before you put the lid on.

 

Pete

[lmnp]

Since producing the sound box shown above almost a year ago, I have started to cover the back of the speaker so that it is fully enclosed this does improve the sound quality no end and the Shenker class 37 in Dave's videos has a fully enclosed sound box fitted.

 

Good, that's the information I needed. I'll put a back onto the sound box tonight. Hopefully that will cut out some of the high end hiss that seems to be present on the sound recordings.

 

Cheers

 

Richard

[sixteen 12by 10s]

Good, that's the information I needed. I'll put a back onto the sound box tonight. Hopefully that will cut out some of the high end hiss that seems to be present on the sound recordings.

 

Cheers

 

Richard

 

Hi Richard

 

Don't worry about resurrecting this thread, you have just beaten me to it. I was about to ask the question about covering the top of the sound boxes in but now I have the answer.

 

Are you using a factory fitted Bachmann unit?, I have one and I am a bit worried about the comment on the hiss.

 

I have one straight out the box, I will give it a go latter, and trial it again with the PH sound box.

 

Just for interest, I see your signature photo is of 37190, this loco was used to obtain the original Bachmann sound sample.

 

Thanks all

 

Gary

[lmnp]

Are you using a factory fitted Bachmann unit?, I have one and I am a bit worried about the comment on the hiss.

 

I have one straight out the box, I will give it a go latter, and trial it again with the PH sound box.

 

Just for interest, I see your signature photo is of 37190, this loco was used to obtain the original Bachmann sound sample.

 

Hi Gary,

 

I've got the Howes refurbished 37 sounds, they are extremely good and definitely captured the spirit of the 37. Sealing in the sound box has cut down some of the hiss, but it is still present. I think it is due to the low bit rate of the LokSound chips. It is most noticeable on startup and after shut down if I leave the air 'tick' on. During general running, it is not noticeable.

 

I wasn't aware that 37190 was used for the Bachmann sounds, thanks for the info

 

Cheers

 

Richard

[Will Vale]

The speaker enclosure looks very good, thanks for posting such detailed instructions. I might well have a go.

 

I finally got around to this, and I thought I'd post my scruffy version to show that even hapless kitchen table bodgers like myself can make one of these. Be warned! It's not as pretty as Pete's original...

 

 

I don't possess a circle cutter, or indeed a pair of compasses, so I made the ring by scribing around the 23mm speaker, nibbling to a rough circle with side cutters, and then filing it to shape. Then I found a suitable coin and scribed around that to get the inner circle. Some drilling,

snipping and much filing produced a reasonable ring, although I managed to snap one side in the process. Still, it was very easy to glue it back together while mounting it to the base. I'm afraid I drilled the holes by eye...

 

For the sides I again ransacked the kitchen for something of about the right radius. I got a measurement wrong (check twice) and made the sides about 2mm too high initially, so after I had the box together I had to spend some time with a very large file adjusting it severely. Luckily, fitting the speaker and lid was easy, and I tidied up the sides a bit afterwards with a fine file to hide my shame. As advertised, it fits really well in the 21 pin chassis and looks a lot better for a coat of black paint:

 

 

The sound is good, there's still a little hiss but it's less tinny than the Bachmann factory-fitted 37, and the key exhaust notes and beat of the idle come through well. I'd do a video but I want to figure out why I can't read the CVs on this chassis before I put the lid on (again - it's been off and on half a dozen times while I got everything fitted). I was also wondering about making a very thin fan replacement and mounting it (plus a plasticard shield) atop the speaker to hide the view of the cab lighting contacts through the fan grill.

 

Anyway, huge thanks to Pete for designing and describing this, hopefully if I can make one anyone can

 

Cheers,

 

Will

[tractor_37260]

Hi Richard

 

Just for interest, I see your signature photo is of 37190, this loco was used to obtain the original Bachmann sound sample.

 

Thanks all

 

Gary

 

As a point of interest, as/if 37 190 was used to obtain the original Bachmann sound sample, 37 decoders with these sound samples ie Bachmann and possibly some SWD's should ideally be used in Class 37/0's only. Refurbed 37/4-5's etc were fitted with alternators and starter motors - 2 off. On the Howes Class 37 refurbed sound decoder, you can hear the starter motors whining prior to engine fire-up. Their 37/0 version (un-refurbed) sounds different. Both Howes 37 decoders are well worth a listen BTW! before parting with any bucks !

Ken

[sixteen 12by 10s]

 Hi

Yes, 37190 was definitely used for the Bachmann / SWD sample, i was in the back cab with the chap, with the hamster on a pole out the window, D212 was hanging on the back for a bit of load.

Spot no about the starter motors, the refurbish ones start of the generator, and the power pickup is slightly more aggressive.

Gary

[Mattmaz]

Hi,

 

Here is a clip of my 37/0 fitted with a Howes unrefurbished sound decoder. Far better IMHO.

 

Regards,

 

Matt

[cassey jones]

Nice video of the Howes.