Has anyone found a source for the discontinued 16 ohm / 5watt BF0000033 speaker?
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This is an option:
I use generic 16 ohm speakers, the fact that it was a 5W speaker isn't that critical as it never saw close to 5W from the electronics.
Hi Carl,
Yes those are the ones I'm looking for.
Mthrailfan, I checked your link, those speakers are only rated at 1 watt.
Your thoughts guys: Would a MTH 4 ohm speaker with a 10ohm, 5 watt resistor work? Would the resistor be wired in series or parallel with the speaker? Or Lionel has some 16 ohm speakers, but rated at 2 watts, these would work OK John?
Any 16 ohm speaker 1w or better would be fine. You do not want to start adding resistors to match impedance on a speaker. Audio quality would be effected. G
Don't add resistors, all you're doing is cutting down the audio volume. 2W speakers will work fine.
Resistor in series mainly lowers the volume. Chuck's example would lower by at least 2/3 rds.
FWIW I have used a 4 ohm speaker in an MTH amp designed for 16 ohms. It made the best sound I have ever heard from MTH. There is a lot of bass penned up in those sound files that aren't able to strut their stuff with those wimpy 16 ohm speakers. Ran it for about 30 minutes and it didn't blow up as expected. I eventually put in a proper 16 ohm speaker.
This is case of do as I say not what I do.
Pete
Norton,
I have used a 4 ohm speaker in an MTH amp designed for 16 ohms.
In general, that's not recommended. Using a lower impedance speaker than the audio amp expects increases volume, however, it can also damage the audio amp.
Going the other way, using a higher impedance speaker than the amp expects will typically lower the volume, however, it will do no harm to the amp.
I understand that Barry. I am not recommending that to anyone else, just mentioned it because contrary to theory as well as common belief the amp did not die despite my driving it as hard as I could. I guess a lot depends on how much overload protection is built into the amp.
It sounded good though, as good or better than any legacy system.
Pete
Norton posted:It sounded good though, as good or better than any legacy system.
I'd have to hear that to believe it, my VL-BB sounds VERY good. 
gunrunnerjohn posted:Norton posted:It sounded good though, as good or better than any legacy system.
I'd have to hear that to believe it, my VL-BB sounds VERY good.
Here is the speaker I used. Just put it in an enclosure and try it your self.
Pete
No offense Pete, but a single speaker being driven by an overloaded MTH amplifier on the old 5V PS/2 board with the typical PS/2 5V sound file isn't going to match the latest Legacy offerings. This is the kind of hyperbole that strains credibility for me.
Since it's obvious I'm not going to hear it, we'll have to agree to disagree on your observations. I personally think putting them side by side would eliminate any doubt, but that ain't gonna' happen.
I don't know what the solid state audio amplifiers in these engines are exactly, but solid state amplifiers in general are a very low impedance like 0.1 ohms. So using 4 ohm or 16 ohm speakers seems would affect the volume. Interesting about the low frequency sound. The amp was able to put out some current with the low impedance speaker?
Thank you everyone for your expertise. So resistors is not the way to go. I'll order some 16 ohm 2 watt speakers from Lionel, they are the same size.
cjack posted:I don't know what the solid state audio amplifiers in these engines are exactly, but solid state amplifiers in general are a very low impedance like 0.1 ohms. So using 4 ohm or 16 ohm speakers seems would affect the volume. Interesting about the low frequency sound. The amp was able to put out some current with the low impedance speaker?
You're correct that if the amplifier is up to the task, a lower impedance speaker will tend to be louder. That's simply because the amplifier can deliver more power to the lower impedance speaker. However, you run into the power dissipation rating of the amplifier.
FWIT, the amp used in the old 5V PS/2 boards is a TDA7056A. It's rated at 3 watts into 16 ohms, but that's if you don't mind 10% THD! It'll also drive an 8 ohm speaker to 5 watts, but still there's that 10% THD. At lower volumes, the THD is much more reasonable, 1/2W offers a typical .3% THD, 1% maximum THD driving a 16 ohm load.
Thanks for the details on the amp John. That certainly helps to make an informed decision on what speaker to use. BTW, some setups I've seen is two speakers in series to make up the design impedance.
But you do not control the amp output. The Sound file does. For what it is worth, many early engines came with the 16 ohm .5W speaker. I personally have never had to replace one for going bad. But according to MTH they did get over driven and fail, so there was the 2W version that looked like the PS-1 8 ohms and finally the 5W. So any of the older 16 ohm speakers would work. I would go with a 8 ohm before I went with a 4 ohm if forced too.
If you watch the amp meter with a 5V board on the test set, no smoke and in neutral, you can get pretty high peak amp with certain engine sound files. In fact there was one model they had to revise the sound file and knock audio down 3db during start up because the peak current of the audio amp was causing the 5V regulator to kick out.
The problem I have found with some other speakers is the size, especially height. Fine in a tender, but may be an issue in a diesel fuel tank. 2mm can make a difference. G
Speakers in series and parallel are commonly used to match the impedance. In truth, usually the speaker impedance is selected to allow the two to be used. Lionel uses two speakers in a lot of their Legacy steamers. When using more than one speaker, you do need to pay attention to phasing the speakers properly, if they're out of phase the sound level will be greatly reduced and you'll very little bass, the sound will be very "tinny".
George is right about the sound, I was surprised at the current peaks with a full volume sound file at times. While the amplifier is rated for 8 ohm speakers, it would also draw more current with a lower impedance speaker. Using an 8 ohm speaker, you'd be more likely to need a higher wattage speaker.
There's another factor in changing the impedance of a speaker for a given amplifier, normally harmonic distortion will increase with lower impedance speakers / higher power output.
You can see this in home stereo specs where the harmonic distortion is measured at different speaker impedances.
Harmonic distortion is an interesting phenomenon, to some people it sounds louder and ok, and to others it sounds distorted, adding a "buzz" to the sound for some. (It's also the "trick" the tv ads use to "sound louder" but not violate FCC rules on max "volume")
Also, harmonic distortion can cause more heating and force on the speaker and can cause accelerated failures.
The findings of hi-fi and audiophiles apply here, albeit normally in "smaller measure".
Greg
Greg Elmassian posted:There's another factor in changing the impedance of a speaker for a given amplifier, normally harmonic distortion will increase with lower impedance speakers / higher power output.
That was my previous point with the specs for the amplifier used on the PS2 5V boards. You go from less than 1% THD for 1/2W to 10% at 3 watts or more. I don't know about other's listening preferences, but 10% THD ends up generating more noise than actual usable sounds to me. 
I completely agree, but I do keep meeting people who cannot hear the difference. So, to each his own, sound quality is so subjective, I almost cringe when people ask for the "best speaker" or "best sound".
I was an audiophile for a long time, and I'm of the opinion that almost everyone can "learn" to hear nuances and distortion and flat frequency response, but it can spoil you forever darn it!
Greg
I have a tin ear and I can hear the difference. 
