Hi Folks

Hopefully my last question about this…Iv’e checked out numerous web sites and threads about sound on the crest-revo system and can`t find a specific answer to this one… I have two other locos using aristo speakers (8 ohm - 1 watt). I’d like to add a speaker to my LGB Forney.( no sound right now) What I have is a 6 ohm - 5 watt speaker that will fit. From my understanding, I can use a speaker less than 8ohm but I’m not sure. Also, is 5 watts output too much?

Any one running anything similar?

Thanks

Mike

Ref’ George Schreyer’s pages;

http://girr.org/girr/tips/tips12/small_speaker_tips.html > electrical characteristics

The way I read his ‘notes’, with 5 watt rating you won’t blow the speaker. But on the impedance side of it, with a lower ohm (only 2 units lower though) you might have a problem.

doug c

Thanks for the response Doug,

My overall confusion comes from the fact that I can’t find any specs on impedance from any of the Crest literature. The aristo speakers I have are 8 ohm and I thought 6 ohm would be OK. I’m no expert on the subject but I thought that the impedance of the speaker changed with frequency response anyway so 6 ohm would be close enough. It’s not like I’m throwing a 32 ohm speaker in it.

Wondering if anyone has “blown up” the sound circuitry on one of these things and has a “sad tale” to tell - or a warning

Mike

Many audio units have ratings for different speaker impedance ratings.

Zimo rates their audio large scale decoders for 10 watts in to a 4 ohm load, and only 5 watts for 8 ohms.

Trainli does have a 4 ohm FRS8 speaker available ( these fit nicely in 1/20.3 tenders). Rest are at least 8 ohms.

So one can have 2 8 ohm speakers in parallel to get max output.

The Zimo HO decoders are 3 watts.

Unless the locomotive has an Aristo-Craft speaker installed, I use Phoenix Sound speakers. They are more robust than the Aristo-Craft speakers. I have never blown an Aristo-Craft speaker myself. But I did have a customer blow the one in his Dash 9 after I installed a Revolution receiver and Phoenix Sound P8.

Thanks for the insights Paul.

My main concern was doing damage to the revolution Rx itself. Can’t seem to find any specs/ratings for speaker wattage/impedance so I was wondering what others have had success with. I have run 8 ohm speakers with no problems but I was wondering if a 6 ohm/5W speaker could damage the Crest sound system. It is a great little speaker with good sound but I don’t want to damage the board.

Mike

If you are unsure, then to be on the safe side, stick with the standard 8 ohm speaker. Some other manufacturers units will work with a 4 ohm speaker, and some caution the user to not use a 4 ohm speaker because it will damage the unit. Since 6 ohms is 75% of 8 ohms, that is quite a significant variance, and if the unit isn’t built for that kind of variance, it could, possibly, cause damage.

Of course I defer to anyone who has better knowledge of the unit and can say yes or no with certainty.

I used a visaton FRS5 speaker in my LGB forney, and are available in 8 ohm, round or square plus can handle a peak 10 watt/4 watt average.

14.95 at Trainli.

What David said, especially in light you cannot get replacement units.

6 ohms is a weird value, is it actually rated 6 ohms, or did you measure it?

Greg

It’s rated at 6 and tested at 6 so I’m not going to use it - I’ll get an 8ohm unit that fits and keep the wattage low too. Don’t want to blow up a crest board at this point.

Mike

Good choice. But an ohm meter (DC) tends to not give an accurate measurement of impedance (AC). But if that is what it is labeled, then I sure wouldn’t risk it.