did i blow out my fostex 127e's?

[crappyjones123]

ive had a pair of fostex 127e's in small monitors for a while and was feeding them with a t amp. yesterday i found an ada pf 200 power amp (200 watts) and (stupidly) plugged the speakers into the amp. after about a minute's use, i turned off the amp and went to get another cd. came back and turned on the amp again and the drivers sounded like they had a sore throat. turned off the amp immediately and started smelling some burnt electronics. the smell was coming from both speakers, not the amp. tried running the speakers with the t amp again and they sounded like they had been blown out.

any ideas why/how this happened?

any suggestions on what i can do with the drivers now? is fostex nice with driver rma's? its been longer than a month so i cant return them to madisound.

thanks,

cj.

[dhenryp]

I assume you didn't start playing them at ear bleed levels. The only other way I could see that happening is if you were feeding them very low frequency at very high levels with no subsonic filter in the path. What was your music source? I've heard of warped records causing this.

[crappyjones123]

source was portable cdp. song was kinda bassy. volume was VERY tame.

[chrisb]

Short answer is, yup - they're probably toast.

I can certainly attest that it doesn't take much in the way of DC current to free the smoke from the voice coils of the FE127/FE126.

Even if they haven't fully fused, the heat was probably enough to delaminate the coil windings from the former, and you're likely hearing the coil scraping against the wall of the flux gap. The smell is the glue attaching the coil to the former and/or the enamel on the wire.

Game over

Several years back I had a short in power supply of one channel of a DIY Audio group buy mini-aleph amp (entirely my fault for sloppy assembly), which resulted among other things in the full DC rail running through a paralleled pair of FE127 in a bipole enclosure.

As I frequently listen in a darkened room, I could actually see a light orange glow from the front driver before they stopped working altogether and the smell clued me in.

There was come charring and damaged components on the amp PC board as well.

As a rudimentary test of the amp, use an 8ohm 5 watt resistor load and measure for DC voltage - don't be surprised to find something higher than a couple of volts.

[Glowbug]

is fostex nice with driver rma's?

I've never dealt with returns to Fostex, but generally most speaker companies won't warranty thermal or mechanical damage that was the fault of the user.

Chalk this one up as a learning experience

[crappyjones123]

but but...they have so many drivers...they cant give me just 2? just a measly pair =/

[infinia]

turned off the amp immediately and started smelling some burnt electronics. the smell was coming from both speakers

Sounds like you smoked em out
Blowing them out IMO would consist of ripping the suspension or making the VC leave the slot indefinately.
I had my share of both types

[planet10]

The "new" amp is probably spewing DC in its output... the FE127s are likely toast, but they are still useful. The cones can be made into a great template for adding the trifoil used to help get rid of the 7kHz peak.

dave

[chrisb]

as painful as these lessons can be, just thank your stars that wasn't a pair of Lowthers sacrificed to the god of blue smoke

get the (now much more expensive) amp tested