Hello one and all:
I have 4B made in 1981, per serial number, home version (no xlr) which I just had recapped, new cord etc done at Bryston Limited.
I wonder about retrofitting DC offset protection, since popping the coils of two not-cheap Altec 15-inch 416 bass drivers, NOT because of the amp but because a loud high pitched transient with what I presume to contain some DC voltage was sent through from a tube preamp as it was warming up with a malfunctioning protect relay of its own.
I see those naked speaker protection boards, with soft-start and offset relays, out of China on eBay and Amazon but they seem to need space inboard and rely on their own power from the amp’s power supply. Then there’s the question of how much they can handle in a DC spike situation without welding the relay contacts together.
What I’d like is some outboard deal that runs in-line with the speaker wires and has its own power supply for the relay, say a 12-volt wall wart or something. Not sure that’s feasible but I could use it with other non- protected direct coupled vintage amps like the DC 300, if I wanted to. Nowhere can I find such a thing, maybe I’m missing the right search words.
Any ideas?
Mr. Tanner if you’re reading this can you tell me please is this something your service department could retrofit?
Thanks,
Jon Archibald
Peterborough Ontario
