"Patrick Turner" wrote in message
...


You either like em or dismiss them.

But this issue of reliablity crops up time and time again.
But most SS amps will need a fix sooner or later like all boxes full of
electronics costing a grand or two.

My 1982 Phillips tele has needed 3 fixes worth an average of $100 each
since I
bought it
in 1982. It now needs fix no 4, and it lies dormant and useless since it
went phut
again before the last
olympics. I am better off without the brain interference of TV.

**My 1968 Marantz Model Eighteen Receiver has been operating every day, in
my workshop, since 1978 (dunno about it's history prior to that), with only
one fix. I allowed it to operate into a damaged speaker for about 30 mins,
before it carked it. Except for the CRO (a tube, I might add) it has not
missed a beat, since the last service (ca; 1985).



I fix amps for a living, and the shed is often cluttered with SS amps
whose output
stages have fused.
Then there is the constant stream of noise faults, intermittent drop outs,
and switch failures. Nothing lasts forever.
There are constant phone calls for service for 3 in 1 stereo systems where
the
complexity is fragile and the CD player mechanisms give up or malfunction.
I try to avoid fixing them, since owners don't like paying much.

An ARC SP8 preamp came in the other day. In 1/2 an hour I was able to
check
the whole circuit out easily. One half of a 12AX7 had stopped working.
I just plugged another in, and it should last 20 years.

**Or not. Most tubes go microphonic after awhile.


Many of the ancient amps made by Quad, leak etc have fragile output
transformers. These are indeed expensive to rewind to the original spec,
so its
better
tp replace the OPTs with something made recently, because the quality of
the old
OPTs
wasn't very good.

There was no active protection fitted to old amps so they
would sometimes sustain a fused OPT winding if a tube decided to
run red hot and saturated with say 300 mA instead of the usual
bias current of 50 mA. This wasn't enough to cause a fuse to blow.
This was often caused by loose grid connections or stuffed coupling caps.

Old gear needs all the caps and resistors changed, and all the plug
and socket joints tightened up.

There are many Quad II amps still being used after 50 years.

I have never seen a faulty switch in a Quad 22 control unit, but
I have seen plenty of rotten carbon comp resistors and lousy
Hunts caps.

**The power switch on the 22 is a notorious problem. I've serviced at least
three, in my memory. The resistors are a real problem, of course, in any
product of that vintage.


I wonder how many average quality SS amps made now will still be in
service in
2054?

**My Marantz Model Eighteen will be (except for the CRO). Same deal with my
regular audio equipment. One of my amps dates back to 1978 and is not only
still working fine, but it still sounds better than most contemporary
products.


Will anyone be carrying the workshop manuals then?

**They'll be on the web (along with everything else). Almost nothing that is
published today, will be lost.

Will anyone be able to fix anything or have the spare parts?

**Possibly not. Tubes will be real hard to get in 2054. Real, REAL hard.

Will anyone need to fix it?

**Probably not. Assuming the planet does not get destroyed within the next
50 years, future developments will probably ensure that amplifiers will be
completely disposable items.


Maybe there won't be any need for audio visual equipments except a brain
implant
device to convey it all by RF digital signals to suit our brains own
digital
signals.

**A very real probability. I recall sci-fi novel which suggested such a
thing.


( I assume there will be people with brains, but since I see a few about
now without a brain, there will always be samples where there is room for
what would be a manufactured improvement).

Perhaps far more breathtaking experiences can be sold to folks to pipe
directly
to the brain cells.

Maybe we won't need a PC either.

**That is a given. PCs are an interim step.


--
Trevor Wilson
www.rageaudio.com.au