Cracking/intermitent 2441

[Lee in Montreal]

The 2441s worked very well for a while. Until sometimes on wouldn't work, unless I cranked the volume up, and down to normal volume. It was an intermitent situation, that started repeating more and more often. Then sometimes when working, it would cut out and come back.

All wires and amps are 100%. I removed the driver's rear cover and cleaned all screws from corrosion. Removed the diaphragm. What can I do?

Should I remove the plastic phase plug and lightly sand the magnet's walls to remove the white corrosion or any debris? If so, how can the phase plug be removed?

I will put my 2445 back to work while I put attention to the 2441...

[ivica]

The 2441s worked very well for a while. Until sometimes on wouldn't work, unless I cranked the volume up, and down to normal volume. It was an intermitent situation, that started repeating more and more often. Then sometimes when working, it would cut out and come back.

All wires and amps are 100%. I removed the driver's rear cover and cleaned all screws from corrosion. Removed the diaphragm. What can I do?

Should I remove the plastic phase plug and lightly sand the magnet's walls to remove the white corrosion or any debris? If so, how can the phase plug be removed?

I will put my 2445 back to work while I put attention to the 2441...

Did you check "L-pad", may be some contact problems

[1audiohack]

That's no good! Is it on it's own amp channel? I have had amps do exactly that too. I am pretty sure the phase plug is anodized aluminum. There was a thread where someone took one completely apart to replace the plastic throat that probably explains how he got them out.

Is it one of the drivers I sent you?

[Lee in Montreal]

That's no good! Is it on it's own amp channel? I have had amps do exactly that too. I am pretty sure the phase plug is anodized aluminum. There was a thread where someone took one completely apart to replace the plastic throat that probably explains how he got them out.

Is it one of the drivers I sent you?


It does the same on different amps. And there's no L-Pad as it goes directly out of the amp, thanks to digital crossovers. I will take the 2441 apart again and recheck continuity of the diaphragm, as well as rubbing marks on the coil. The diaphragm itself doesn't seem to be marked.

[Lee in Montreal]

STOP THE PRESSES!!!

Looks like the intermitent problem is not coming from the 2441 as it repeats with the 2445.

I am swapping amps, XLRs and other interconnects to try to isolate the problem. Will keep you posted.

[Mr. Widget]

STOP THE PRESSES!!!

Looks like the intermitent problem is not coming from the 2441 as it repeats with the 2445.

I am swapping amps, XLRs and other interconnects to try to isolate the problem. Will keep you posted.That sounds more like it... if it had been in the driver, I would have thought it might be a very small "open" in the VC.

...and no, you can not pull the throat etc. without first demagnetizing the driver.


Widget

[Lee in Montreal]

I think I have found the pervert effect of running 112db drivers at home at low volume.

Spent many, many hours tracking down the source of the problem. Swapped drivers. Side to side. 2441 with 2445. Swapped interconnects between digital crossover and midrange amp. Swapped speaker wires. No resolution of the problem. But I do have a few clues.

The previous power amp was working fine until it started having the intermittent problem. To restart the drivers, I had to crank up the volume a bit. Then the sound would be fine for a while. Sometimes not. Then fine again when the amp has been working for at least an hour. When I swapped to another amp for the midrange, it initially would work fine, then the same problem would reappear. Again, if I crank the volume, the sound is fine.

My question is: because of the high efficiency of the 2441/2445 drivers, if I want to listen a low volume, then I must send very low signal to the amp, which barely works. Is that possble that if amps are ran at very low output for a while, it can have some detrimental effect on them?

Just to test my theory, if I listen at a higher volume, I get none of the disapearing midrange channel.

[Eaulive]

My question is: because of the high efficiency of the 2441/2445 drivers, if I want to listen a low volume, then I must send very low signal to the amp, which barely works. Is that possble that if amps are ran at very low output for a while, it can have some detrimental effect on them?

No, not at all. What you're describing is most likely due to a corroded contact, it could even be before the amp.
When voltage reaches a certain value, it arcs across the bad connection and reestablishes the contact temporarily. This will probably get worse as time passes.

An improperly adjusted bias in a final stage could cause distortion (called crossover distortion) at very low volume and this becomes inaudible at higher volumes, but it doesn't have the "switch on" effect when you drive it harder, it's only a distortion that fades away as volume increases and comes back when volume decreases.

Check contacts, cables, inputs and outputs connections. Does the amplifier have relays on the speaker lines?

[Eaulive]

When the mid goes, does the signal indicator on the amp keep flashing?

[Lee in Montreal]

Does the amplifier have relays on the speaker lines?

Yes. Both amps that had problems have output relays. Currently playing the mids on another amp and it works just fine.

BTW I still have three P2200 and one PC2002 whispering your name...;-)

[Eaulive]

BTW I still have three P2200 and one PC2002 whispering your name...;-)

Well they are welcome, I told you already two months ago I was ready to give them love :D

[Lee in Montreal]

When the mid goes, does the signal indicator on the amp keep flashing?

The amps have protection lights, but no level leds. The protection lights don't kick in.
Now, knowing that he problem isn't with the drivers nor the digital crossover or the interconnects, I will focus on output/input levels.

[Eaulive]

Yes. Both amps that had problems have output relays.

If the relays are accessible during use, when the problem occurs try to tap on the relay with a screwdriver handle for example, and see what happens

[Mike Caldwell]

The next time it happens leave things just as they are and take any speaker ( smaller the better for sake of convenience it could even be just a speaker component) take the leads from that speaker and touch them to the output terminals on the amps driving the speakers/drivers that are not working and see if you get sound at that point. Also you could take your "test speaker" to the terminals on the driver and see what you have there.
Do not disconnect or change any of the connections in your system while doing this so as to not throw off the test by possibly resetting an intermittent connection. The "test speaker can be a piece of junk as long as it makes sound!