tube amp/flutter in speakers?

Unless it's a rare output transformerless (OTL) design, your amp has an output transformer between the power tubes and the speaker. This transformer will not pass DC unless it is seriously defective, in which case you'd likely have more severe symptoms such as smoke and overheated output tubes.

If it's not coming from an upstream component, then as mentioned above, low frequency oscillation is the likely culprit.

I agree that it's time for a trip to the shop.

Ghostrider, don't believe the old wives tale about transformers not passing DC. It's a lie. They will pass DC, just not anywhere near as effectively as they do AC. Sean
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Sean, was that a KISS concert or AC/DC where you so the flash out of the speaker?

if this helps, i have tried other speakers on the amp and no problem. could the heil driver be the culprit.

I have no idea what it might be. Keep in mind that some speakers are capable of going MUCH lower in frequency response than others are. I have one set of speakers that will throw madly at 5 Hz while others do not flicker in the least. As such, your ESS's with their passive radiator loading may be revealing a problem that the other speakers simply can't reveal. Either way, i would not chance damaging ANY of your equipment without first having them checked out.

Glen, i've seen flame-out's at several different shows. The most significant one that i remember was at one of my buddie's shows. His bass amp ( Gallien Krueger ) started leaking DC and the speakers began smoking and then literally spit out flames. People thought it was like Ace Frehley's old "smoking Les Paul" routine. The reason that i remember this one so vividly though is that they were MY bass cabinets that he ignited !!! Needless to say, he replaced the drivers with brand new ones. I didn't come out of that one too bad, as i ended up with 4 brand new 18" drivers that cost about $180 apiece : ) Sean
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