Replies to This Discussion

Permalink Reply by Tony Davies on September 13, 2013 at 5:04am

http://www.wikihow.com/Measure-Speaker-Impedance This gives a step by step method with pretty pictures#

Permalink Reply by Bluesheart on September 13, 2013 at 6:03am

OK thanks, so it is an 8 ohm speaker (reads 7.2 on meter) . That is what is recommended. SO do I just have unrealistic expectations of how loud it will be. I have a ruby amp I made with a 3" speaker that cranks! Also a Honeytone through a 3" speaker and it is really loud ( for a small amp) . Maybe this speaker is defective??

Permalink Reply by Tony Davies on September 13, 2013 at 6:05am

Maybe you need a pre amp in the chain?

Permalink Reply by Bluesheart on September 13, 2013 at 7:17am

The pre amp helps but still not  at all I guess what I was expecting. I'm going to try my harp mic through it and see where that gets me.

Permalink Reply by Bluesheart on September 13, 2013 at 7:35am

Oh wow, now that is more what I expected! There ain't nothin' wrong with the speaker, that is for sure! My "Shaker" harp mic got all the dogs in the neighborhood howling! No pre amp. So I guess I just have a lot to learn about the output of various kinds of pickups. I do not have a "regular" electric guitar with a magnetic pickup but I guess it would be similar to the volume I'm getting with the mic?  I'm more likely to use it as a harp amp anyway and not a guitar amp so I guess I should consider it a success. Now I just need  to find a place away from the dogs so I can open her up !

Thank you for all the help!

Permalink Reply by Bluesheart on September 13, 2013 at 8:57am

Open mic night, here I come!

Permalink Reply by Bluesheart on September 13, 2013 at 9:19am

Permalink Reply by Jeff McFadden on September 13, 2013 at 4:44pm

The speaker probably has an impedance marking directly on the magnet, 4 or 8 ohms.  If, however, there is a transformer gizmo in there, the transformer is to allow the speaker to be connected to a high voltage PA line.  If there is a transformer, disconnect it from the hookups directly on the speaker back and hook your little amp directly to those hookups, and you should be ok.

Most of those wall mounted speakers had transformers for high voltage lines, and I'd be surprised if you could hear the speaker at all if you're connected through one of those.

I used to do commercial PA as part of my livelihood and put in a bunch of those.

Permalink Reply by Bluesheart on September 14, 2013 at 1:37am

Thanks for the tips Jeff but there are no markings or a transformer or resistors or anything. I verified with my ohm meter that it is 8 ohms. I also connected a couple of other, smaller and newer 8 ohm speakers and got pretty much the same output levels. I'm not even sure if this is the original speaker or not since the cover over the magnet sticks out in back, it would not mount flat on the wall. I really think it is just a matter of having the right kind of input level as using a preamp helped some and using my harp mic (w/o the pre amp) gives the volume levels I was expecting. I imagine if I plug in a guitar with magnetic pickups I'll get output similar to the mic. Seems that piezos don't do so well with it. I do not experience that with my Honeytone amp though, it seems to be able to crank no matter what I connect to it. 

Permalink Reply by Jeff McFadden on September 14, 2013 at 4:42am

I've got a rod piezo in my CBG and it sure has wimpy output. I'm planning to build a little Smoky-type LM386 amp in it for a pre-amp and see if that fixes it.