Lance:

Definetly open the amplifier up and with a good 100 Watt spot-lamp give her
a good look.

If you have never upgraded the Power Supply or Power Tube Bias components
now is a great moment to consider this.

Look for signs of anything that is discolored, charred or smells like it has
'cooked'

Whatever you do to your Mac's consider that the other Monoblock will be next
in line for an inspection as well.

A whooshing sound can be any number of things. In my experience a failing
power supply cap emits a spitting or ticking sound. Whoosh from the speakers
has to be from a DC short of a Signal Cap or some other component that has
failed after so many years of faithful service.

Thanks,

Ricky
wrote in message
...

hi, i have a pair of old mac 50-w2 mono blocks and one got sick tonight.

the first symptom was a rushing noise a few seconds after the amp was
turned on, much like being between channels with a old tube AM radio.

i powered it off and suspecting a tube swapped tubes with the working amp.

problem satyed with the same amp - so not likely a tube.

i then swapped outputs to the speakers - problem stayed with the amp -
so not the speaker.

when i put it all back together and tried again, one of the output
tubes flashed blue and the fuse blew.

when i've had similar problems in the past, it's been a bad tube,
but it doesn't look like that this time.

thoughts?
--
Lance