Umm… my Quest Z’s still work when they’re unplugged from A/C?

[soundacct]

Just wondering, how is this possible?

As I type, they’re unplugged and still working fine. I broke out the audio test tone recordings and everything. My hearing is not as good as when I was younger, but I can still hear up around 18kHz. No doubt about it, the panels are working, and loud enough to hurt my ears when I crank it up.

My other ML’s do not do this - they all stop working.

 

[Robert D]

The charge on the diaphragm stays awhile. Im not sure how long, maybe 5 minutes or so? Its a static charge built up on it.

 

[soundacct]

The charge on the diaphragm stays awhile. Im not sure how long, maybe 5 minutes or so? Its a static charge built up on it.

well, it's a heck of a static charge!

it worked for like an hour when over time the mids & treble declined and I noticed the amp was working harder to maintain volume (it has meters). By morning, it didnt work at all.

 

[Robert D]

well, it's a heck of a static charge!

it worked for like an hour when over time the mids & treble declined and I noticed the amp was working harder to maintain volume (it has meters). By morning, it didnt work at all.

Ok. I've never tried it more than like 1 song. Good to know. I know it takes awhile for it to discharge just sitting there. I figured playing them would cause it to discharge faster since the diaphragm is moving.

 

[john65b]

The ability for an ESL speaker to continue playing after AC power is removed is sign of a healthy panel. Be happy.

But driving ESL panels with very low or no charge on them will damage your step up transformer and / or amplifier.

 

[Leporello]

But driving ESL panels with very low or no charge on them will damage your step up transformer and / or amplifier.

I've heard this to be true. With no charge, the panel looks like a pure capacitor to the driving circuitry. What damage may occur depends on that driving circuitry, but it's definitely not a good idea, so I've never tried it for more than a few seconds.

 

[john65b]

Yup. I personally know of a Quad ESL-63 that suffered this fate....a friend preferred to plug his Quads into a switched room light outlet to save energy (even tho leaving them plugged in all the time only consumed milliwatts). His wife wanted to listen to some music one day while he was out, and kept turning the volume up.

Good news is more than half the Quad ESL-63 ads on ebay are for parts/ repair...so now he has plenty of spare parts, and has also learned a thing or two! His amp was one of these Class A amps that can also be used as a welding machine - no issues.