Friday 8 June 2012

Goodman Mezzo 2 speaker capacitors

I did some stuff on this a while back but never quite got a reply to the question, as to why a noise was on one speaker and what did the circuit board in the enclosure do?

http://ckdboats.blogspot.com/2011/09/speaking-to-your-selfhow-hard-can-that.html


This is part of the frequency control board, I have now found on a forum that the capacitor (in blue) can age and would affect the audio. I have checked out its markings, Hunts, Reversible. 8uf 150v dc JB2973 T AYI



I now need to source two new ones, one for each speaker to balance things out.
News in today on what some parts may do,

I don't know what that circuit does in the speakers - I suspect
its job is to split the high-frequencies for the tweeter vs the low freq for
the bass/woofer thing. The circular coils are "toroids" - they act as
frequency filters and chokes.

Info on the same subject as supplied by ham man Justin, so I know a lot more on the subject than when I started this morning.


Inside the Goodmans Mezzo 2 speaker, I can change the capacitors myself.

News from my technical bod friend in England, I had sent him a link to a forum discussing similar speakers with two different capacitors in.

Hi Roy,


I read through that guys question and I think the short answer he received is sound advice. If you have different caps on similar speakers that is odd but it all depends on what the caps are doing. As sound is dependant on frequency to activate the speaker coils and therefore the diaphragm to move the air?

You don't want too much smoothing or you end up with almost DC so its very important to stick to the makers range. If there is high pitched noise coming through I would think it means that the high frequency smoothing is not doing its job and it could be as a result of a deteriorating capacitor. As they are quite cheap things, if its easy to replace them it may be worth while as they don't last forever and are very simple things inside just layers of what looks like tin foil and some sort of insulation which can break down over time. mf is microfarad while the other one for which I have no key on the computer is peaka-farad or something like that and is very much smaller.

I assume these different caps are in different parts of the circuit? I would think the larger ones the mf are to deal with base frequencies while the peaka's are to do with high frequency but I'm no expert on sound systems. If you do change them use identical caps in both speakers, however they may have used different ones due to some variation in the speaker coils, it only takes a couple of extra windings on one speaker for it to require different treatment.

Notty.

Sounds like good advice as Notty says.

Roy

March 28th 2013.

I have managed to find some caps to the same specification, they are in the post so I will soon be able to change the existing ones for the new ones. The old ones will be about 47 years old, time was not on their side?

More on the subject when the new ones are fitted.