Electrocompaniet AW-250r problem. help please

maxzimum

Member
2005-02-11 12:48 pm
Hi,

My Aw-250r just started giving me the following problem.

On low volume the sound in my speakers keeps cutting in and out (like a loose connection somewhere). If I turn the volume up it goes away and stays OK at low volume till I stop the source for more than a few minutes.

I have checked everything and determined that the problem is with the power amplifier somewhere. Till last evening the problem was with the left channel and now it is with the right channel.

The amplifier is less than a year old but since there is no distributor for Electrocompaniet in my country, warranty is a problem.

Would highly appreciate some assistance.

Thanks.
 

maxzimum

Member
2005-02-11 12:48 pm
Hi,

Sorry for the late response to this post as I just got down to checking the problem.

I took the plastic covers off the relays, sprayed some WD40 on the contacts and cleaned them. Not only has this seemed to have resolved the problem but I think it's sounding better too.

Now my question is, what could have caused the relays to degrade so soon (about one year). Also, the contact quality seems to be very poor to be in the signal path - so is there a way to safely bypass the relays?

Thanks in advance..
 
I can see that you live in India. Can it be that the humidity is too high? The relays utilized by EC are neither sealed, nor good quality. Maybe you can get hold of some hermetically sealed relays. Also, in my opinion you should not only spray them, but also wipe them with some metallized sanding paper, and them treat them with some electrically lubricant/preservative.

Regards
Roar
 

maxzimum

Member
2005-02-11 12:48 pm
Hi Roar,

It's not really humid where I live, except when it rains (June-August), but is pretty hot and dry.

I was reading somewhere about a snubber circuit - capacitor connected to the relay contacts. Is this something I can use?

Else, do you know off any hermetically sealed relays that I can replace the stock ones with?

I am simply amazed at how much sonic difference the cleaning of the relays has made specialy in the HF.

Thanks.
 

djk

R.I.P
2001-02-04 4:23 am
USA
Relays generally have a bit of a wipe-ing motion to the contacts.

Speaker relays that fail early on generally don't have this action and get dirty fast. I generally replace them (leaving the cover off), and after soldering spray Deoxit in the contacts (and then snap the cover back on).

I have also added film caps around 0.047µF~0.1µF in parallel with the contacts (if you have the volume up you will hear a little HF bleed through before the relay closes).
 

djk

R.I.P
2001-02-04 4:23 am
USA
"Also, the relay in the amp has 4 poles.. 2 for the + and 2 or the -. Where do the caps go? "

You need two caps here, one for each set of contacts.



"what to you mean by HF Bleed?"

A faint amount of treble will be heard if you have the volume control up (which you should have turned down last time you turned it off, but forgot to).
 

maxzimum

Member
2005-02-11 12:48 pm
Thanks..

So the capacitor is put between each pole - bypassing the relay N/o contacts.

The HF bleed should not be a problem since my preamp powers on with the Volume at 0 and with the Mute ON. It also has a ~40 sec. delay before outputing any sound.

I assume the caps are bipolar. What should their voltage rating be? And should I add a resistor or something like this:
http://www.tedss.com/snubber
 
I am more or less forced by my conscience to say this: If you have to ask these questions, you are not competent to do these alterations. The 250W is a fragile amp, it does not take much to blow it. Then you end up with 12 blown output devices. Think about it. I accept that you would like to learn, but the learning curve might end up being very steep.
 
Hello everyone, I am a problem with symptoms identical to the Maxzimum user who opened this topic.

I opened the AW250R and examined the left channel relay (which is failing) and it looks normal by checking with an electron microscope.

What I notice is still that the channel where it cuts the sound is heating up more than the right channel.

Would anyone have any direction to get me through?

I did not move the relays because to remove them to clean is very complicated according to my technician, we preferred not to move since there were no visible signs of problem in the relay.

Thanks so much for any help!