Arfa Daily wrote:
Anyone by any chance got a set of schematics for a Mission Cyrus amp to
hand ? It has a small DC offset on one channel. Not large, but enough
for the protect circuitry to see it as a problem. Unfortunately, I am
seeing lots of tantalum bead caps in it ... :-(

Arfa

No, but I did have an alarming offset incident with my Cyrus 2 about 5 years ago.
I was about to sell it to this girl I knew, so I got out a damp cloth, and
gave the top and sides a good rubbing to remove the dust, before she came round.

I'd had the thing for years by this time, with no problems.

She came round, I let it rip, and it nearly blew the cones out of the
speakers I was also selling her, with HUGE static DC offset out of both channels.

As soon as I'd shat myself, I yanked the power and plugged another amp into
the speakers. Luckily they were fine, but I measured the DC out of the
Cyrus 2 at about 20V each side.

So I sold her the speakers, which were fine ever since, but had to apologise for
the unbelievably Sod's-law-esque failure of the amp, and she bought one
elsewhere.

Days or weeks later, I decided to give it another go with a multimeter on
the outputs. No offset. Plugged in speakers - fine again.

Obviously my "damp" cleaning cloth had been a bit more than damp, and dripped
water into the amp, causing the offset temporarily.

I'm still using the same amp now!


Martin